Home Medication Inventory Method to Assess Over-the-Counter (OTC) Medication Possession and Use: A Pilot Study on the Feasibility of In-Person and Remote Modalities with Older Adults

Abstract

Background:

There is a need for reproducible methods to measure over-the-counter (OTC) medication possession and use. This is because OTC medications are self-managed, variably monitored by healthcare professionals, and in certain populations such as older adults some OTC medications may introduce risk and cause more harm than benefit.

Objective(s):

To develop and assess the feasibility of the Home Medication Inventory Method (HMIM), a novel method to measure possession and use of OTC medications.

Methods:

We benchmarked, adapted, and standardized prior approaches to medication inventory to develop a method capable of addressing the limitations of existing methods. We then conducted a pilot study of the HMIM among older adults. Eligible participants were aged ≥60 years, reported purchasing or considering purchasing OTC medication, and screened for normal cognition. Interviews were conducted both in person and remotely. When possible, photographs of all OTC medications were obtained with participant consent and completion times were recorded for both in-person and remote modalities.

Results:

In total 51 participants completed the pilot study. Home medication inventories were conducted in-person (n=15) and remotely (n=36). Inventories were completed in a mean (SD) of 20.2 minutes (12.7), and 96% of inventories completed within 45 minutes. A total of 390 OTC medications were possessed by participants, for a mean (SD) of 7.6 (6.3) per participant. No differences in duration of interviews or number of medications reported were identified between in-person and remote modalities. Anticholinergic medications, a class targeted in the pilot as potentially harmful to older adults, were possessed by 31% of participants, and 14% of all participants reported use of such a medication within the previous 2 weeks.

Conclusions:

Implementing the HMIM using in-person and remote modalities is a feasible and ostensibly reproducible method for collecting OTC medication possession and use information. Larger studies are necessary to further generalize HMIM feasibility and reliability in diverse populations.

Introduction

Total over-the-counter (OTC) retail sales reached $32 billion in 2019 in the United States (US)¹ and the number of OTC medications available continues to increase.^2–4 OTC medications can be used to manage symptoms for several acute and chronic conditions commonly experienced by older adults and do not require prescriptions from physicians or advanced practice providers. It is estimated that 50% of older adults use at least one OTC medication regularly and older adults consume nearly 30% of all OTC medications.⁵ However, some OTC medications may pose risks to older adults⁶ and have been associated with the risk of falls, dizziness, confusion, cognitive impairment, and dementia.^6–9

To improve OTC medication safety, we must have feasible, reliable, and valid methods to measure what and how OTC medications are consumed. This presents a significant problem because unlike prescription medications, which are prescribed, dispensed, and monitored by healthcare professionals and electronic medical record systems, OTC medications are purchased autonomously by consumers in retail establishments that frequently do not have a healthcare professional available to support safe decisions or monitor patterns of use. Currently, methods to collect possession and use of prescription medications are not directly transferrable to measuring OTC medications.

Clinicians and researchers have an interest in capturing OTC medication use to understand prevalence, change over time, and the impact of interventions targeting safe OTC medication practices.^5,10,11 Presently, there is no standardized method to reliably identify and describe OTC medication use among community-dwelling older adults. Previously published methods, summarized in TABLE 1, each have strengths and limitations, especially as they pertain to subgroups such as older adults.

Table 1:

Method to describe OTC medication use

Methods for obtaining OTC Medications	Description of the method	Strengths	Limitations
Electronic Health Record (EHR) review12-17	Data gathered from documentation in a section of the EHR, e.g., medication orders, active medication list, text notes, visit notes and administration notes. Data may contain order date, medication name, strength, route of administration, frequency, duration, and refill information.	- Low effort and cost to researchers, participants. - If present, may provide detailed or granular data (e.g., dose, indication, dates of use). - OTC medications can be captured from a variety of interactions including telephone calls, nurse visits, procedure, and provider visits. - Not as prone to recall or social desirability bias if data were recorded by professional.	- Data may be missing or lacking detail due to interrater unreliability or training of the user/enterer. - Data may not be broadly available due to federal requirements (e.g., HIPAA) or institutional restrictions (e.g., access rights policies). - EHR data format, quality and design may vary between institutions. - Data varies based on clinician or clinic documentation practices. - Data in an institution’s EHR may not contain data from other institution. - Data may be scattered across the EHR fields in structured and unstructured form. - Data on past OTC use may not be available, depending on how it was documented. - Accuracy may still be a problem if records based on self-report of participants.
Structured self-report surveys and diaries18–20	Participant-reported medication information on a standardized survey or in a diary/logbook kept by participant. Contains data fields requested from or volunteered by participant.	- Low cost and effort for researcher. - Often more accurate or up to date than EHR data. - Potentially better reproducibility and accuracy when conducted by a patient/participant rather than multiple researchers or clinicians. - Conducted at convenience of participants.	- High burden on participant, especially among those using multiple or frequent medications. - Subject to accuracy and reliability concerns due to respondent memory, literacy, cognitive function, motivation, or interpretation of instructions. - Over- or under-reporting due to social desirability. - Potential for missing data, intentionally or not. - Subject to intra- and inter-individual reliability concerns due to variability in reporting of self-administrations. - Burden of instructions text needed to standardize reporting may be high. - More difficult to target specific medication classes (e.g., anticholinergics or NSAIDs) for in-depth follow-up, when participants lack knowledge of which medications belong to these classes.
In-home inventory with direct medication inspection5,10,21–23	Trained interviewer collects data from participants in the home. Information is obtained by direct observation of medications in the home regarding medication name, strength, and dosage form, whereas frequency and duration of use are captured by asking participants.	- The interviewer can guide questions to obtain an accurate and comprehensive medication list by direct observation. - Burden is distributed across both participant and data collector. - Overcomes self-report issues by supplementing with direct observations. - Can train data collector to standardize data collection.	- Validity in phone or internet-based inventories not established. - No currently available protocol or training materials available. - May be time and resource intensive, especially if special training required.

One of the more frequently employed approaches to acquire OTC medication information is an in-home inventory with direct medication inspection by trained research personnel.^{5,10–21–24} This method has been used in studies of younger and older community-dwelling adults. Nonetheless, existing literature lacks a detailed description of how to effectively implement this method, which limits its reproducibility. Two in-home inventory studies reported 42% and 43% prevalence of OTC medications,^5,22 whereas other studies found 31% OTC medication prevalence when using self-reported surveys¹⁸ and 70% prevalence when using electronic health record (EHR) review.¹⁶ Different methods may provide variable rates of sensitivity to detect OTC medication use, depending on study design, targeted study population, and definitions for counting OTC medications.

One key aspect of an ideal method of home medication inventory is the ability to capture all OTC medications available to a patient (referred to as possession) and provide accurate descriptions of patterns of use. In addition to this, the inventory should be capable of collecting medication use characteristics such as dose, frequency, and indication. Of particular relevance to the older adult population is the ability of a method to identify and describe high-risk medications, such as anticholinergic medications, that may introduce more risk than benefits and are variably reported in observational studies^7–9. However, existing literature on in-home inventories with direct medication inspection is limited in the details on how to implement this method.⁵ Specifically, the literature lacks information on the training received by the interviewer, required interviewer qualifications, definitions for counting and categorizing multi-ingredient OTC medications, the time required to conduct the inventory, and the feasibility of applying such methods in different settings.

Our primary objective was to develop and assess the feasibility of the Home Medication Inventory Method (HMIM) in a pilot study to measure possession and self-reported use of OTC medications. Secondly, we sought to identify the prevalence of one class of high-risk medications in older adults, anticholinergic medications, to test the HMIM for detecting specific types of medications in support of a specific research or clinical question. The goal of the HMIM is to standardize the reproducibility of the medication inventory methods as they may be employed in clinical and research environments. This work straddled the COVID-19 global pandemic, allowing a natural experiment of performing the HMIM in-person and remotely, thus we present our experience conducting inventories through both modes of delivery.

Methods

Development:

In preparation for method development, 3 pharmacist-researchers (KA, MC, NC) and 2 non-clinician researchers (RH, JS) reviewed the published literature to assess available methods to collect home medication inventories and use patterns for community-dwelling older adults. Authors also interviewed a researcher with experience conducting home medication inventories⁵ to gather recommendations for the protocol, including definitions for medication data variables, handling OTC medications with multiple ingredients, and training research staff.

During development, the team particularly attended to the definition of the term ‘inventory’ by including OTC medications that are both routinely used/consumed at the time of data collection and those possessed but not recently used (within past two weeks) at the time of data collection. The justification for this approach is derived from the knowledge that OTC medications can be used to control intermittent symptoms (such as seasonal allergies),^25–27 along with the findings that even intermittent use of certain medications can contribute to adverse outcomes over time. ^28–31 One group of OTC medications considered high risk for older adults is anticholinergic medications,⁶ due to the higher rate of adverse events including dizziness, constipation, dry mouth, falls, and possibly dementia that can impair quality of life. More to this point, we designed the method to have the capability to identify OTC anticholinergic medications defined by the Anticholinergic Cognitive Burden (ACB) scale, ³² and subsequently collect medication name, strength, frequency, duration and indication.

The HMIM includes explicit decisions to support reproducibility and transparency for defining and collecting OTC medications. First, we decided to include audio recordings and collect pictures of OTC medications reported during each of the home medication inventory visits to increase the internal validity. Second, we established a standardized definition for counting OTC medications to improve interrater reliability (see Other Data Collection section below). This approach also provided an understanding of the time requirement for detailed information capture.

Testing/Feasibility:

We tested the feasibility of the HMIM by conducting a cross-sectional study from November 2019 through September 2020 in Indiana and Wisconsin. Test sessions were performed individually with consenting older adult participants and consisted of five general elements: (1) eligibility evaluation, (2) informed consent, (3) collection of OTC and prescription medication information (counting and listing drug names), and (4) collection of detailed medication use of a subgroup of OTC medications (anticholinergics), (5) structured inventory questionnaire on medication management support elements. Participants were compensated with $20 either as a gift card or cash.

Participants and Eligibility:

Eligibility criteria included community-dwelling adults at least 60 years of age^5,28 who reported purchasing or considering the purchase of an OTC medication for themselves in the last year. Age ≥60 years was chosen as an inclusion criteria given that the World Health Organization (WHO) defines older persons at this age cutoff.³⁷To increase reporting accuracy, we excluded individuals with dementia based on a score of 3 or less on the Six-Item Screener (SIS), a telephone-based cognitive screening tool. The SIS is a global measure of cognitive status with diagnostic properties similar to the Mini-Mental State Exam (MMSE). The SIS can be administered by the telephone or face to face, making it suitable for our multimodal method. ³³ Ethical approval was provided by the Institutional Review Boards (IRBs) of both Indiana University and the University of Wisconsin. In March 2020, COVID-19 related restrictions on human subjects research required that we adopt remote methods for recruitment and data collection, thus we describe recruitment and data collection for both in-person and remote methods.

Recruitment for In-Person Inventories:

In-person inventories were conducted in two senior assisted living facilities in Indiana and at the home of participants’ in Wisconsin. At each Indiana senior housing facility, staff members helped distribute study advertisements and arranged for a researcher to present the study directly to residents. Interested residents then scheduled individual appointments. For participants recruited in Wisconsin, recruitment was facilitated through an independent retail pharmacy that advertised our study, leading to participants contacting our team for eligibility screening and in-home appointment scheduling.

Recruitment for Remote Inventories:

Remote inventories participants were solicited via social media networks of our investigators and the email lists of the Indiana Clinical and Translational Sciences Institute. Participation was limited only to residence within the United States. Respondents were invited to virtual screening and consent sessions, followed by data collection using their preferred tele-video option such as Zoom^™, Skype^™, FaceTime^™, WebEx^™, or telephone calls.

Audio Recording and OTC Medication Photographs for In-Person Modality:

In-person inventories were audio recorded using a digital voice recorder. At the end of each inventory, the interviewer captured a still “group photo” of the front faces of all OTC medication packages and individual photos of the drug facts side of all anticholinergic product packages (as requested by the interviewer). This was done to capture home medication details for subsequent verification of data recorded during the inventory and as-needed supplementary post-hoc data entry.

Audio Recording and OTC Medication Photographs for Remote Modality:

Remote inventories utilized an audio recording tool available in each video-conference application or by using the voice memos recording application if the inventory was conducted by telephone. When possible, the interviewer used screen-capture software within the video-conference apps to collect still photos of OTC medication packages as described above. For telephone inventories or if the screen capture images were unclear, the interviewer asked participants to collect the photos by themselves and text (Multimedia Messaging Service (MMS)) or email them to the interviewer.

Interviewer Training:

All inventories were conducted by a third- or fourth-year Doctor of Pharmacy (PharmD) student or a pharmacist researcher. Interviewers were selected for their familiarity with nomenclature of medication names, ingredients and different pharmaceutical dosage forms of OTC medications. This approach is justified by other work conducted in this area in which a small percentage (2.7%) of medications collected could not be identified.¹⁰ The training of interviewers included an initial one-hour introduction to the HMIM processes, included the consenting processes, and explanation and definition of variables to be collected. Following the introductory session, interviewers were asked to review materials before a second training session approximately one week later during which questions could be answered and study procedures could be demonstrated during a simulated inventory with trainer feedback to ensure interrater reliability among interviewers.

Inventory Structure:

In-person and remote inventories shared the same structure and flow. The inventory began with an introduction to the nature and purpose of the study by the interviewer, followed by the following participant assessments: (i) participant identifiers;(ii) confirmation of intent to participate; (iii) ascertaining the primary person managing medications (participant vs. other); (iv) request to gather both prescription and OTC medications, and finally (v) communication about the expected duration of the inventory (See Appendix 1 for inventory script). Following these introductory steps, the interviewer initiated the audio recording for the inventory.

Other Data Collection:

We recorded method of inventory completion (modality) and demographic data, including age, gender, race/ethnicity, education, number of medical conditions and employment status. We asked participants about descriptors of medication management support including: where they purchase OTC medications, who made decisions on product selection, who purchased OTC medications for the participant, and whether a pharmacist was involved in the decision to purchase OTC medications.

Medication Data Collection:

OTC Medications Review:

To begin the medication review, the interviewer documented the total number and names of all OTC medications including all products considered medications, herbals, and supplements. As opposed to other work conducted in this area that collected only medications used in the last two weeks,⁵ we did not restrict number of OTC or prescription medications given that we captured all medications possessed in the home and documented whether they had been used in the past two weeks or not.

Anticholinergic OTC medication Review

As a proof of concept to capture medication details of high risk medications in older adults, we captured product-specific data for OTC anticholinergic medications identified as strong or definite anticholinergics according to the ACB scale (score of 2 or 3).³² The interviewer recorded the anticholinergic drug name, strength, participant-reported frequency, duration of use, indication, and whether the product had been used in the last two weeks. All strong anticholinergics possessed by participants were included regardless of use in the last two weeks. Label instructions from the product were also recorded, to make sure the interviewer documented all active ingredients with consideration for OTC medications that have more than 1 active ingredient (Appendices 2,3).

Prescription Medications Review

Following the review of OTC medications, the interviewer documented the total number and names of all prescription medications. Subsequently, the interviewer identified and counted anticholinergic prescription medications (ACB score of 2 or 3). For each prescription anticholinergic medication, the interviewer recorded the anticholinergic drug name, strength, participant-reported frequency, duration of use, indication, and whether the product had been used in the last two weeks.

Definitions for Counting Medications

We collected only orally ingestible medications and medication patches, excluding topical products, intranasal applications, or injectables, based on a judgment decision by the authors.. Our decision to focus on orally ingestible medications and medication patches, while excluding other forms like topicals and intranasal, was driven by a need to balance the comprehensiveness of data collection with practical considerations. This approach was deemed most feasible and relevant, considering the widespread use and significant health impact of these forms of medications in older adult populations. Collecting possession and use pattern of OTC medications was the primary aim of the HMIM feasibility study given that many OTC medications are consumed on intermittent/unpredictable schedules. All products were considered unique unless they were the same product/manufacturer, strength, and dosage form. The justification for this approach accounts for the variability in health literacy suggesting that not all participants recognize that a branded product may contain the same ingredient as a generic product (i.e. two products may contain the same active medication but have two different labels). Products with the same active ingredient but in generic and branded packages, different strengths or dosage forms, were counted as two unique products. For example, Advil^™ tablets 200 mg and generic ibuprofen 200 mg tablets were counted as two different medications.

Analyzing/counting med possession and use

Based on our definition of a medication inventory, we captured all medications possessed in the home, regardless of whether it had been used/consumed in the past two weeks or not. We defined current use by the consumption of a dose within the last 2 weeks, while all other anticholinergics in the home were defined as ‘possession but not current use’.

Analysis of Feasibility:

In order to test the feasibility of the HMIM, we assessed descriptive measures of inventory and instrument completion, including time and modality. Total inventory time, time to complete OTC medication data collection, time to complete anticholinergic medication data collection, and the proportion completed under 45 minutes for each modality are reported. Additionally, we report descriptive statistics of the inventory, which includes demographic characteristics and medications identified.

Results

Participants and Demographics

A total of 79 people responded to invitations or advertisements to participate. Fifty-one (65%) were screened, enrolled, and completed the inventory. Twenty-six (33%) did not respond to subsequent attempts to schedule a study visit, and 2 (3%) were not scheduled due to COVID-related interruptions in human subjects research. There were no eligible participants who directly refused to participate in the study. The mean age [standard deviation] was 69 [8] years, 80% were female, 51% were White/Caucasian, and 47% were African American (Table 2). Additionally, 25% of participants had a master’s or other advanced degrees, 43% had a college degree, 22% had some college education, and 4% completed high school or a general education diploma. Furthermore, 78% of participants were retired, 16% were part-time employees, and 6% were full-time employees. Of the 51 participants, 57% reported more than one medical condition, 29% reported one medical condition, and 14% reported no medical condition.

Table 2:

Population Demographics

Variable	Total N=51	In-person N= 15	Remote N=36
Mean age (in years) (SD)	69.4(7.7)	67(7.6)	66.6(5.9)
Gender: Male (%)	10 (19.6%)	3 (20 %)	7 (19.4 %)
Gender: Female (%)	41 (80.3%)	12 (80%)	29 (80.5%)
Race: White/Caucasian (%)	26 (50.9%)	12 (80%)	14 (38.8%)
Race: African American (%)	24 (47%)	3 (20 %)	21 (58.3 %)
Race: Hispanic/Latino (%)	1 (1.9%)	0	1 (2.7%)
Education: some high school (%)	1 (1.9%)	1 (6.6 %)	0
Education: High school graduate or GED (%)	2 (3.9%)	1 (6.6 %)	1 (2.7%)
Education: some college (%)	11 (21.5%)	3 (20%)	8 (22.2 %)
Education: College degree (%)	22 (43.1 %)	5 (33.3%)	17 (47.2%)
Education: Masters or other advanced degree (%)	13 (25.4 %)	3 (20%)	10 (27.7 %)
Education: missing (%)	2 (3.9%)	2 (13.3%)	0
Employment: Full time (%)	3 (5.88 %)	0	3 (8.3%)
Employment: Part time (%)	8 (15.6%)	1 (6.6 %)	7 (19.4%)
Op Employment: Retired (%)	40 (78.4%)	14 (93.3%)	26 (72.2%)

Feasibility

In-person home medication inventories were conducted with 15 participants, and a remote home medication inventory was conducted with 36 participants (Zoom™=19, Facetime™=1, and telephone=16). In both modalities, we were able to collect an audio recording for all inventories. All variables were collected for each participant. Images of medications were collected for 96.1% of participants.

Inventory Duration, Overall and by Modality

Medication inventories were conducted in less than 45 minutes in 96.1% (49/51) of participants. The mean [SD] total inventory time was 20.2 [12.7] minutes. The mean [SD] OTC medications inventory time was 6.4 [5.9] minutes. The mean [SD] time to complete the OTC anticholinergic medication inventory was 5.2 [4.2] minutes, which captured medication use characteristics including name, strength, frequency, duration, and indication among users of these medications. Feasibility time stratified by modality is further reported in Table 3.

Table 3:

Feasibility Time Stratified by Modalities

Feasibility Time	In-person N= 15	Remote N=36
Mean inventory time: Total (in minutes) (SD)	22.1 (17.1)	19.4 (10.5)
Minimum inventory time: Total (in minutes)	7.4	7
Maximum inventory time: Total (in minutes)	46.7	55
Time to complete inventory: All OTC, mean (SD) (in minutes)	5.1 (6.7)	6.9 (5.6)
Minimum inventory time: All OTC (in minutes)	1.1	1
Maximum inventory time: All OTC (in minutes)	23.5	24
Mean inventory time: OTC AC (in minutes) (SD)	7.1 (5.6)	4.2 (2.8)
Minimum inventory time: OTC AC (in minutes)	1.8	1
Maximum inventory time: OTC AC (in minutes)	17	10.1

Medication Characteristics

All OTC and Prescription Medications

Among the 51 participants a total of 390 OTC medications were recorded (120 (30.8%) among the 15 in-person inventories, and 270 (69.2%) from the 36 remote inventories). Participants possessed a mean [SD] of 7.6 [6.3] OTC medications, supplements, herbals, or nutraceuticals (range 1–32). A total of 236 prescription medications were reported, with 81 (34.3%) reported among those completing in-person inventories and 155 (65.7%) reported among those completing remote inventories. The mean [SD] number of prescription medications was 3.4 [ 4.6] (Min: 0, Max: 13),

OTC and Prescription Anticholinergic Medications

Among the 51 participants, 16 participants (31.4%) possessed a high-risk OTC anticholinergic medication and 7 participants (13.7%) reported using one in the last two weeks. Out of the total 25 OTC anticholinergic medications in possession, 9 (36%) were combination products with another pharmaceutical ingredient(s) such as an analgesic or cough/cold product. Diphenhydramine was the most frequently reported anticholinergic ingredient (65.3%), followed by chlorpheniramine maleate (15.3%). Insomnia was the most frequently reported indication for OTC anticholinergic medications (34.6%), followed by allergy (30.7%). Among anticholinergic OTC medications for which frequency of use was assessed, 42.3% reported using OTC medications intermittently or occasionally.

Four participants (7.8%) among the 51 reported using a prescription medication with anticholinergic properties. Among those possessing a prescription anticholinergic, 25% reported using at least one dose in the last two weeks (2% of all participants). As shown in Table 4, the prevalence of participants possessing an OTC anticholinergic medication was four times higher than those possessing a prescription anticholinergic medication.

Table 4:

Medication Use Characteristics Among Study Participants

Descriptive Variable	Total N=51
Number of OTC medications, mean (SD)	7.6 (6.4)
Number of OTC AC medications (in possession), mean (SD)	0.5 (0.9)
Number of OTC AC medications (in use), mean (SD)	0.2 (0.4)
Number of Rx medications, mean (SD)	3.4 (4.6)
Number of Rx AC medications (in possession), mean (SD)	0.1 (0.3)
Number of Rx AC medications (in use), mean (SD)	0.03 (0.2)
Anticholinergic (AC) prevalence
Proportion in possession of an OTC AC medication	31.4%
Proportion in possession of a prescription AC medication	7.8%
Proportion in possession of either OTC or prescription AC medication	31.4%
Proportion in possession of both OTC and prescription AC medication	5.9%

Purchasing and Use Behavior

Responses to OTC medication management items indicate that 87% of participants purchase OTC medications themselves, while 7% reported that a family member purchases OTC medications for them. Fifty-seven percent reported that they make their own decisions about what and when to take OTC medications, while 34% reported healthcare professionals’ involvement in their decision in purchasing and using an OTC medication. Participants reported that purchasing OTC medications from a variety of retailers: (29%) from the same place they purchase their prescription medication, (26%) from a big box store (Walmart, Target, Costco), and (16%) from a different pharmacy from which they get prescriptions. Additional sources include grocery stores and online websites (16%, 10%, respectively). Pharmacist involvement in the decision to purchase OTC medications varied between participants; 25% reported asking the pharmacist about the location of OTC medications, while 24% reported having asked the pharmacist about a recommendation for OTC medication use, and 19% asked a safety question about OTC medication (for example, is this safe to take with my other medications?). Fifteen percent reported asking a self-care appropriateness question (For example, should I take an OTC medication or go see my doctor?). Lastly, 9% did not report any pharmacist involvement in the decision in purchasing an OTC medication.

Discussion

We have developed the HMIM to systemically identify and record OTC medication possession and use, and tested it through both in-person and remote modalities with 51 community-dwelling older adults. No eligible participants refused to participate in the study in either modality, reflecting a high acceptability rate. Total inventory time and the time to complete OTC medications data collection were similar in both modalities. Thus, our method can be used to overcome challenges and inconsistencies on home medication data collection in clinical care and clinical research by limiting the interviewer’s time needed to travel to participants’ homes and limiting safety and health concerns (as in the COVID-19 pandemic). As remote fieldwork continues to gain prominence in the wake of the COVID-19 pandemic, more researchers are turning their attention toward remote methods. With careful planning, preparation, and ongoing support, remote fieldwork can successfully overcome the challenges presented by traditional, time-consuming in-person modalities.^38–41 Thus, conducting the HMIM through both modalities can lend agility to researchers and clinicians interested in identifying up-to-date OTC medication lists that can optimize medication reconciliation and medication management decisions.

Results from our feasibility study demonstrated a higher mean number of OTC medications possessed by participants than the mean number of prescription medications (7.6 and 3.4, respectively). A study by Qato and colleagues found a higher prevalence of prescription medications compared to OTC medications among older adults (81%, 50% respectively). In contrast, our study showed that participants possessed more than twice the number of OTC medications compared to prescription medications. The differences in the prevalence of OTC and prescription medication between our study and Qato et al. may be drawn from our inclusion criteria, the definition of possession vs. current/recent use, or differences in comorbidities. We did not perform a comprehensive assessment of comorbidities as in other studies, and it is possible our feasibility study was conducted in a generally healthier and more educated population.

The ability to differentiate between possession and current use of OTC medications is particularly crucial in those with difficulty accessing the healthcare system, have financial constraints, or face barriers in obtaining prescription medications who rely on the access to OTC treatments. Additionally, the HMIM differentiates possession from current use to identify medications that are used intermittently, while traditional inventory methods may ignore such medications.

Our findings revealed a higher prevalence of OTC anticholinergic medications (ACB score of 2 or 3) possessed by our sample (31.4%) compared to prescription anticholinergic medications (7.8%). Two studies conducted by Campbell and colleagues found a higher prevalence of prescription anticholinergic medications among older adults (28%, 11% respectively) than our present sample.^43,44 Prior work identifying anticholinergic prevalence among older adults is often drawn from populations interacting with the healthcare system and uses medical records to identify anticholinergic medications. Our findings focusing on OTC anticholinergic medication prevalence support the need for improved detection of anticholinergics and other potentially risky medications in older adults that may be available as OTC medications.

Based on our findings, many OTC anticholinergic medications were used intermittently or unpredictably, depending on season or presence of symptoms. Because cumulative exposure to some medications such as anticholinergics contributes to the risk of adverse outcomes,^28–30 we believe measuring even occasional use of medications is important. The HMIM included a process to capture medication details such as strength, frequency, and duration specifically for the purpose of measuring cumulative use over time, which can be used to evaluate long-term risk for adverse outcomes and represents an improvement on prior methods.

The HMIM has other advantages. First, our multi-modal allows flexibility without sacrificing feasibility. Second, the HMIM is accompanied by interviewer training instructions to improve standardization and reproducibility in data collection (See Appendix 4,5, and 6 for Approaches to Standardization and Interviewer Training Procedures). Third, The HMIM offers the advantage of supplementing self-report with direct observation, which helps to overcome issues of recall bias and intentional underreporting. This approach also enables the interviewer to guide questions and obtain accurate and comprehensive medication lists through direct observation. Fourth, audio recording and photographic data collection allows the interviewer to focus on engaging with the participant rather than taking notes. This may result in more positive, interactive, and informative communication with the interviewees. Fifth, our method included all medications possessed or available to participants in their home regardless of use in the last two weeks to capture medications that may have delayed effects or risks.

The HMIM also has some notable limitations. First, while the HMIM addresses self-report concerns, direct observations may not be possible for all participants. For example, while in-person and remote modalities using one of the video conference applications allowed for direct observation, these capabilities are dependent on participant’s familiarity and access to technology and may result in variation in reporting and confirmation of medication details. Second, while our training and procedures accommodate multiple delivery modalities, the validity of the HMIM has not yet been tested across these modalities within the same participant, nor has reliability across multiple raters been evaluated. However, we believe the standardization of the training materials supports interrater reliability. Third, The HMIM may be impacted by differences in medication packaging across geographic regions or countries.

In addition to the HMIM limitations, our feasibility study also had some limitations that should be taken into consideration. First our sample size is appropriate for a feasibility study, but interpretation of medication use characteristics is limited. Second, while our sample is racially diverse, it is not considered ethnically diverse. Previous studies demonstrated that race and ethnicity influence OTC and prescription medication prevalence.^21,44–45 Those studies aimed mainly to assess the prevalence of medication use between White/Caucasians and African Americans with little representation from Hispanic/Latino populations. Third, our study population overrepresented highly educated participants, who have been shown to have more knowledge regarding medication safety when compared to those with less education .⁴⁶ This overrepresentation might have influenced our findings, as educational level can impact medication use patterns, health literacy, and reporting accuracy, , impacting the validity of our results across a broader population. Fourth, we did not evaluate the potential impact of language barriers on HMIM accuracy for participants who primarily spoke languages other than English. Fifth, our feasibility pilot study did not make a direct comparison of the reliability of in-person and remote modalities. We recognize that there were more participants in the remote group (36 participants) than in-person group (15 participants), which could make a direct comparison between the two modalities challenging.

Future studies should focus on evaluating potential disparities and sociodemographic differences that may impact the accuracy and feasibility of the HMIM method. Specifically, future work should investigate the impact of social determinants of health, including language barriers, access to technology, and health literacy. Additionally, future research should aim to recruit a more ethnically diverse sample to assess potential differences in medication possession and use patterns across racial and ethnic groups. Such research can contribute to improving health equity and reducing health disparities related to medication use. Ultimately, addressing these factors will enhance the applicability and effectiveness of the HMIM method in diverse populations and ensure equitable access to safe medication management. Moreover, the validity of self-reported medication data, especially for OTC products, is a significant issue. Future research should explore methods for validity assessment, such as cross-referencing self-reported medication data with pharmacy records or conducting occasional follow-up home visits with a subset of participants. This approach will increase the reliability of the collected data and provide a more precise representation of medication usage trends. Finally, to improve the accuracy of assessing medication reporting consistency between the two modalities, it is recommended that future studies include an equal distribution of participants in each modality. This will enhance the evidence supporting these methodologies and offer more in-depth insights into their comparative effectiveness and reliability.

Conclusion:

Our HMIM was shown to be feasible through both in-person and remote collection of OTC medications in this pilot study of 51 participants. Remote inventories can serve as a suitable option when in-person inventories cannot be conducted. Moreover, our novel method demonstrated the ability to differentiate possession and current use of OTC medications. This method should be tested in a larger sample size with more diverse participants to better understand OTC medication use characteristics.

Abbreviations:

HMIM

Home Medication Inventory Method

OTC

Over-the-counter

SIS

Six-item screener

EHR

Electronic Health Record

ACB

Anticholinergic Cognitive Burden

Appendix 1: Inventory Script

Introduction

Thank you again for participating in the “Home Medication Inventory” Before we get started, I am FIRST NAME, LAST NAME, a research assistant at (name of the institute). For privacy purposes, can you please confirm your name and date of birth? Thank you for taking the time to participate in this research project. This session may take up to 45 minutes. I only need to gather information about your medications. We won’t be talking about any of your medical problems. We are interested in recording exactly how you take medications, so please feel free to tell us how you take each medication even if it is different from the directions listed on the pill bottles or how the doctor prescribed them to you.

Purpose of interview

The purpose of this inventory is to collect information about medications you currently have at home. These can be medications you are currently using or have used in the past. This will include prescription and non-prescription medications, such as over-the-counter medications, vitamins, and herbal and alternative medications.

In our pre-visit communication, there was mention of a caregiver or family member that helped you with your medications. This is the portion of the call where we would invite them to join us. Need to consent caregiver.

[If they have a family member or caregiver that helps with their medications, consider asking if they are available and willing to participate in this discussion. If they are not available, ask if the participant would be able to review their medications or if it would be more beneficial to schedule a time when the family member/caregiver is available]

Medication Information Gathering

Let’s get started by gathering all your medications – both over the counter and prescription and place them in front of you. If you use any medication lists – such as those you receive from your doctor, please have that handy as well.

Do we have all of your medications here? [If not, give participant a chance to retrieve any additional medications].

Remember, this should include any prescription medications, over-the-counter medicines which are those that you can purchase at a pharmacy or grocery store without a prescription and can include medications like Tylenol, aspirin, Advil/ibuprofen, vitamins and dietary supplements, or herbal remedies. Besides the medicine cabinet or in the kitchen and the refrigerator, some people also keep medications in places like their bedside table or purse – did you check those places as well?

[If they use a weekly pill box, request that they retrieve all the individual pill bottles used to fill the pill box]

Just to make sure we have everything here…

• Do you use eye drops?

• Do you use patches?

• Do you use creams or ointments?

• Do you use inhalers?

• Do you use injectables?

• Do you have any new prescriptions that you have not filled or picked up from the pharmacy?

Now we will go through the medications you have set out. Are you ready to get started?

[Ask the following questions for each medication and document in REDCap]:

1. What is the name of the medication?

2. What is the strength of each tablet/capsule/etc.?

   1. Answer should be in mg, mcg, grams, etc.

3. Each time that you take this medication, how many tablets/capsules/puffs/etc do you take?

4. How do you take this medication? Specifically, what route? By mouth, inhalation, injection?

5. In a single day, how frequently or how often do you take this medication? [Record the way the participant takes the medication if it is different from the directions on the medication list and/or pill bottle]

   1. [For a PRN medication, record an average daily/weekly/monthly dose] On average, how often have you needed to take this medication in a day or in a week?

6. What is the reason for taking this medication?

7. Is this a prescription medication or over-the-counter medication?

8. Approximately how long have you been on this medication?

Closing/Wrap-up

I appreciate you taking the time to speak with me today. Thank you for answering questions about your medications. I hope you have a great day.

Appendix 2: Medication Review Session

Now we will go through the medications you have set out. Are you ready to get started?

Interviewer will count and record all OTC and prescription medications. [Ask the following questions for each Targeted medication (AC) and document in REDCap]:

1. What is the name of the medication?

2. What is the strength of each tablet/capsule/etc.?

   1. Answer should be in mg, mcg, grams, etc.

3. Each time that you take this medication, how many tablets/capsules/puffs/etc do you take?

4. How do you take this medication? Specifically, what route? By mouth, inhalation, injection?

5. In a single day, how frequently or how often do you take this medication? [Record the way the participant takes the medication if it is different from the directions on the medication list and/or pill bottle]

   1. [For a PRN medication, record an average daily/weekly/monthly dose] On average, how often have you needed to take this medication in a day or in a week?

6. What is the reason for taking this medication?

7. Is this a prescription medication or over-the-counter medication?

8. Approximately how long have you been on this medication?

Appendix 3: Anticholinergic Medications Data Collection Form

Appendix 4: Approaches to standardization and FAQ

1. If the participant asks how long the medication inventory is going to take:

This portion of the phone call should take between 25–45 minutes. If you are busy, we are able to call you back at a later time to gather information for the medication inventory. However, this information is an important part of this study, so we strongly encourage you to complete it today if you have the time.

2. If REDCap does not recognize the brand name of an over-the-counter medication:

Option 1:

1. Click on checkbox under “Medications” indicating that medication will be entered as free text.

2. Ask the participant to read out the brand name of the product. Instruct the participant to locate and read out the active ingredients in the product. Participant may need to spell out the ingredients since some ingredients are difficult to pronounce.

3. Document active ingredients in the “Other” field on REDCap; preferentially enter in alphabetical order for standardization purposes

   1. e.g. Equate Tussin CF Max → document “dextromethorphan, guaifenesin, phenylephrine”

Option 2:

1. Click on checkbox under “Medications” indicating that medication will be entered as free text.

2. Ask the participant to read out the brand name of the product.

3. Interviewer will take note of the name, and use Lexicomp, Micromedex, or Google to identify the active ingredients.

4. Document active ingredients in the “Other” field on REDCap; preferentially enter in alphabetical order for standardization purposes

   1. e.g. Equate Tussin CF Max → document “dextromethorphan, guaifenesin, phenylephrine”

Option 3:

1. Ask the participant to read out the brand name of the product.

2. Interviewer will take note of the name, and use Lexicomp, Micromedex, or Google to identify the active ingredients.

3. Interviewer will reach out to Dr. Khalid Alamer who will determine if there is a comparable product that can be entered that is recognized by REDCap.

NOTE - REDCap form should be updated with medication name within a couple days of completion of the interview.

3. Always record the way the participant is taking a medication rather than the way it is prescribed if there is discordance between the two Examples:

1. If the participant reads the directions directly from the pill bottle, prompt the participant to clarify whether they take it differently or exactly as directed Sometimes participants do not take the medications exactly the way it is prescribed. Do you take it differently from those directions listed on the bottle?

2. If there is discrepancy between the contents of the participant’s medication list and the directions on the pill bottle, ask clarifying questions to determine which aligns with the way the participant is currently taking the medication

   I noticed that the directions on the medication list for how you take ______ are different from the directions on the pill bottle. I want to record exactly the way that you take your medications, so do you follow the directions on your medication list or the pill bottle?

4. When documenting PRN frequency, REDCap will require interviewer to enter an average number of doses

On average, how often have you needed to take this medication in a day or in a week?

Select the option that is closest to the way that the participant takes it

E.g. 4 times in the past 2 weeks → 2 times per week

5. When documenting participant’s reason for taking a medication:

1. If the participant does not know the reason, then document as “unknown” on REDCap

2. If the participant has several reasons for taking a medication, then document all reasons as free text on REDCap

6. When documenting length of time the participant has been taking a medication:

If the participant responds with vague terms (i.e. for a very long time, forever, not too long), ask clarifying questions to estimate the year

If you had to estimate how long ago you started this medication, how many years would you say? [If they need further prompting] Is it more than 5 years? 10? 20?

1. REDCap will require you to enter a specific year, so calculate a year based on the estimate provided

   e.g. “Probably 10 years ago” → 2020 – 10 = 2010; enter 2010 into REDCap

7. For all subsequent medication inventories following the baseline visit, in addition to documenting new medications that are started, interviewer should also document discontinuation of any medications

If the participant has discontinued any medications listed on the medication inventory from the previous interview, select “Finished” for “Medication ongoing?”

Ask patient to be as specific as possible by providing the month and year when the medication was stopped. If the participant provides an estimate of ___ weeks or months, interviewer should translate the answer to a specific month and year to be entered into REDCap.

8. If the participant only has a pill box with their medications and does not have access to the individual pill bottles used to fill the pill box:

TELEPHONE INTERVIEW

Option 1:

Find out if they are able to access the pill bottles at a later time and offer to reschedule the appointment.

Option 2:

Request that they describe the characteristics of each tablet/capsule with color, shape, and imprints on each side. Utilize Lexicomp or Micromedex Drug ID to identify each medication to document in the worksheet. Ask participant to identify how they are taking the medication (i.e. number of tabs/caps of each medication and how frequently they are taking it each day especially if it is a pill box with morning/afternoon/evening slots for each day)

IN-PERSON INTERVIEW

Inspect each tablet/capsule and note color, shape, and imprints on each side. Utilize Lexicomp or Micromedex Drug ID to identify each medication to document in the worksheet. Note how they are taking the medication (i.e. number of tabs/caps of each medication and how frequently they are taking it each day especially if it is a pill box with morning/afternoon/evening slots for each day)

9. If the participant asks a medication-related question, acknowledge their concerns and encourage discussion with a healthcare professional

That is a good question. As the interviewer, I am not qualified to answer those questions or make recommendations to address those concerns, but I encourage you to discuss your concerns/questions with your pharmacist and/or doctor.

Appendix 5: Interviewer Training Procedure

Each trainee will proceed through the following training process:

Step 1 Overview and Training (~60-minute group session)

1. Review objectives and medication inventory roadmap.

2. Read through scripting outlined in the medication inventory participant communication template highlighting the necessary information to document.

3. Review the database (REDCap) form for data entry.

4. Review approaches to standardization.

5. Observe trainers conduct a mock inventory to complete a participant’s medication inventory.

6. Distribute rubric that will be used to assess trainee in Step 2 training.

Step 2 Assessment and Certification (~30-minute individual session)

1. Trainee will conduct a mock inventory proceeding through all the necessary steps to complete a medication inventory (i.e. gathering necessary information and properly documenting on REDCap)

   1. Trainer 1 – play the role of the participant
   2. Trainer 2 – serve as the certifier who will evaluate trainee based on rubric
2. Trainers will provide feedback to the trainee.

   1. If the performance is satisfactory, the trainee will be certified.
   2. If the performance is unsatisfactory, the trainee will be alerted to the areas of deficiency and will be given an opportunity to practice on their own until they are prepared to redo the mock interview

3. Once the trainee has been certified, the trainee and trainer/certifier will sign the certification summary (see Appendix III), and the trainee will be approved to begin conducting participant inventories with research participants for medication inventory

Ongoing Quality Assurance

1. Trainers may periodically observe trainees conducting participant inventories with research subjects

2. Trainers may periodically review data collection forms on REDCap

Appendix 6: Rubric for certification

Must achieve “YES” on 87% (13/15) of the rubric to become certified.

Introduction	YES	NO
Interviewer states his/her name
Interviewer states his/her title
Interviewer confirms patient identifiers (name, DOB)
Interviewer states the purpose of the inventory (for medication inventory)
Interviewer asks about primary person managing medications (patient, caregiver)
Interviewer asks patient to gather BOTH prescription and OTC medications

Medication Inventory (as documented on REDCap)	YES	NO
Interviewer completes steps to get to REDCap form for data entry
Interviewer documents the key medication elements (minimum 10/12 to achieve YES)  Medication 1  Medication 2  Medication 3  Medication 4  Medication 5  Medication 6  Medication 7  Medication 8  Medication 9  Medication 10  Medication 11  Medication 12
Interviewer employs standardization techniques:
Approach 1 – Duration of interview
Approach 2 – Active ingredients of OTC med
Approach 3 – Record the way the patient is taking the medication
Approach 4 (minimum 3/4 to achieve YES) – Average PRN doses   Medication 1   Medication 2   Medication 3   Medication 4
Approach 5 (minimum 4/5 to achieve YES) – Reason for medication   Medication 1   Medication 2   Medication 3   Medication 4   Medication 5
Approach 6 – Length of time on medication
Approach 9 – Medication-related question

Comments/Feedback:

Appendix 6: Certification summary

Activity	Date completed
Step 1: Overview and Training (60 minute group session)
Step 2: Assessment and Certification (30 minute individual session)

I have successfully completed all the above training activities.
Tester Name (print)	Tester Signature	Date
The above-named tester is certified in conducting participant interviews and properly documenting data collected for the R2D2 phone/in-person medication inventory
Certifier Name (print)	Certifier Signature	Date