High prevalence of unmet healthcare need among people who use illicit drugs in a Canadian setting with publicly-funded interdisciplinary primary care clinics

Abstract

Background

People who use illicit drugs (PWUD) experience significant barriers to healthcare. However, little is known about levels of attachment to primary care (defined as having a regular family doctor or clinic they feel comfortable with) and its association with unmet healthcare needs in this population. In a Canadian setting that features novel publicly-funded interdisciplinary primary care clinics, we sought to examine the prevalence and correlates (including attachment to primary care) of unmet healthcare needs among PWUD.

Methods

Data were derived from two prospective cohort studies of PWUD in Vancouver, Canada between December 2017 and November 2018. Multivariable logistic regression was used to identify factors associated with self-reported unmet healthcare needs among participants reporting any health issues.

Results

In total, 743 (83.6%) of 889 eligible participants reported attachment to primary care and 220 (24.7%) reported an unmet healthcare need. In multivariable analyses, attachment to primary care at an integrated care clinic (adjusted odds ratio [AOR] = 0.14; 95% Confidence Interval [CI]: 0.06–0.34) was negatively associated with an unmet healthcare need, while being treated poorly at a healthcare facility (AOR = 5.50; 95% CI: 3.59–8.60) and self-reported chronic pain (AOR = 2.00, 95% CI: 1.30–3.01) were positively associated with an unmet healthcare need.

Conclusion

Despite the high level of attachment to primary care, a quarter of our sample reported an unmet healthcare need. Our findings suggest that multi-level interventions are required to address the unmet need, including pain management and integrated care, to support PWUD with complex health needs.

INTRODUCTION

People who use illicit drugs (PWUD) are at an increased risk for mortality,¹ as illicit drug use is often implicated in increased risks of overdose, mental health disorders, and infectious disease (e.g., HIV and hepatitis C virus).^1,2 Worse still, many PWUD report difficulty accessing healthcare^3–6 and delay seeking treatment for health issues to the point where acute care is necessary.^2,4,5 Although primary care settings have been shown to be effective in providing treatment for those with mild substance use disorders, speciality and diverse treatments are needed for those with a higher severity of addiction and mental health comorbidities.² Historically, in both the United States and Canada, specialty treatment for substance use and mental health disorders have been separated from mainstream primary health care services (e.g., family doctors or walk-in clinics).^2,5 This spatial and organizational separation creates barriers in care coordination and forces PWUD with diverse needs to navigate complex healthcare systems.²

To improve healthcare access among this population, in the past two decades, there have been calls to integrate substance use, mental health, and other specialized care services at one location.^2,5,7–12 This integrated healthcare model intends for primary care to be interdisciplinary and patient-centered by unifying several service providers, such as social workers, nurses, psychologists and physicians.^2,5 Research among PWUD has shown effectiveness of an integrated healthcare model in increasing access and care coordination for the treatment of mental health and substance use comorbidities.^2,9–11 Further, integrated models of care have been shown to reduce the cost to the overall healthcare system.^2,11 However, evidence also indicates that the current primary care system does not hold the capacity to fully switch to an integrated model of healthcare without a more diverse workforce and additional resources and training.^2,10

In 2016, the Vancouver Coastal Health Authority (VCH) launched the Downtown Eastside Second Generation Strategy (DTES-2GS), a multi-year healthcare system reform in the DTES neighborhood of Vancouver, Canada.¹³ The DTES is an area with high concentration of substance use, marginalization and criminalization.¹⁴ This strategy has involved the implementation of an integrated interdisciplinary care model at three primary care clinics in the DTES, as well as a range of staff trainings at other healthcare sites to better coordinate care.¹³ Notably, in this setting, a range of primary healthcare services are provided at no cost to patients, as it is publicly-funded.¹⁵ This is of significance as a lack of health insurance coverage is an important consideration for those in the US (where no universal healthcare system exists).¹⁵ The potential impact of the DTES-2GS on addressing the healthcare needs among PWUD in this setting have not been studied.

Past research has shown high levels of unmet healthcare needs among PWUD.^2,16–18 In this population, several markers of social marginalization, including experiencing stigma and discrimination,^19–21 housing instability and homelessness,^18,22 and repeat incarceration,^22–24 have been shown to be associated with an unmet healthcare need. In this regard, examining and improving the attachment to primary care (defined as having a regular family doctor or clinic and feeling comfortable going there) may constitute an important first step to addressing the unmet healthcare needs among this population. While this point has also been raised by local PWUD communities in the DTES as an important area of research,²⁵ to our knowledge, no study has assessed levels of attachment to primary care among PWUD or its association with unmet healthcare needs. The present study provides a unique opportunity to assess both the unmet healthcare needs and attachment of primary care among PWUD in Vancouver, a setting where publicly-funded interdisciplinary primary care clinics have recently been implemented. Specifically, our study objectives were to assess the prevalence of attachment to primary care and unmet healthcare needs and to identify factors of self-reported unmet healthcare needs among PWUD who report having at least one health issue.

METHODS

Study design and recruitment of participants

We used data from the DTES-2GS evaluation study (hereafter referred to as the ‘2GS Supplement’). This prospective cohort study was developed with primary aims of observing the changes in healthcare access and quality that corresponds to the implementation of the DTES-2GS. Data were collected by developing and administering a supplemental questionnaire to a sub-set of two ongoing, well-characterized prospective cohort studies of community-recruited PWUD in Vancouver: the Vancouver Injection Drug Users Study (VIDUS) and the AIDS Care Cohort to evaluate Exposure to Survival Services (ACCESS). Detailed descriptions of these cohorts have been previously published elsewhere.²⁶ In brief, VIDUS enrols HIV-seronegative adults (≥18 years of age) who injected illicit drugs in the month prior to enrolment. ACCESS enrols HIV-seropositive adults who used an illicit drug other than or in addition to cannabis in the month prior to enrolment. The studies use harmonized data collection and follow-up procedures to allow for merged data analyses. The VIDUS and ACCESS cohorts are administered questionnaires by trained interviewers, urine drug screen tests (UDS), and HIV and HCV serologic tests at equal follow-up frequency (i.e., every six months).

Between December 2017 and November 2018, participants returning for VIDUS and ACCESS follow-up interviews were invited to participate in the 2GS Supplement. A convenience sampling approach was taken until 1000 participants provided verbal consent and enrolled in the 2GS Supplement. A convenience sampling approach was taken as the parent cohorts were community-recruited via non-probability sampling methods, as well as have some incomplete follow-ups among participants, which makes random sampling difficult to implement. A baseline (and semi-annual thereafter) supplement interview was scheduled either on the same day as the participant’s parent cohort semi-annual follow-up interview, or within two weeks. Trained interviewers of the parent cohorts administered the 2GS Supplement questionnaire, which was collaboratively developed with local PWUD organizations and elicited information regarding participants’ experiences of access to and quality of healthcare.²⁵ Participants received a $40 CAD honorarium for completion of the parent cohort follow-up, while an additional $15 CAD was given for completion of the 2GS Supplement interview. VIDUS, ACCESS and the 2GS Supplement have received approval from the University of British Columbia/Providence Health Care Research Ethics Board. The current study used data from the 2GS Supplement and the matching parent cohort questionnaires that were administered between December 2017 and November 2018. All participants who completed the questionnaires and reported having a health issue were included in this analysis. For participants who completed the 2GS Supplement questionnaires twice during the study period, the most recent observation was included in the current study.

Study measures

The primary outcome of interest was a binary measure (yes vs. no) of ‘unmet health care need’, derived from the question: “In the last 6 months, was there a time when you needed care but were unable to get it?”.

The explanatory variables of interest included the following socio-demographic characteristics: age (continuous); ethnicity/ancestry (white vs. non-white); gender (male vs. non-male); accessing services or residing in the DTES; anxiety symptoms assessed by the Patient-Reported Outcome Measurement Information System (PROMIS) anxiety short form (moderate/severe vs. none to slight/mild);²⁷ chronic pain, defined as reporting pain that has persisted for greater than three months, which is consistent with the definition of the International Association for the Study of Pain²⁸; and HIV serostatus (positive vs. negative). Drug use related variables included: daily use of heroin (≥daily vs. <daily); daily use of stimulants (≥daily vs. <daily), defined as powder/crack cocaine or crystal methamphetamine; and recent exposure to fentanyl, derived from the results of the UDS for fentanyl.²⁹ Other social/structural exposures included: homelessness, incarceration; receiving healthcare in one place; being treated poorly at a healthcare facility; and attachment to primary care, defined as self-reporting having a regular family doctor or clinic that they feel comfortable going to. This definition was derived from our focus group discussions with local PWUD communities during the questionnaire design phase.²⁵

In addition, we further stratified the attachment to primary care variable by the type of healthcare that the participant most frequently accessed in the past six months. We asked participants: “What is the name of the place you visited most often?”. We then asked: “What type of facility is it?” and responses included: an integrated care clinic, defined as utilizing one of the three VCH’s integrated care clinics in the DTES; a community health centre; an addiction treatment clinic; a private clinic or doctor; a hospital outpatient unit; or a low threshold service, defined as those who report a mobile clinic/outreach healthcare or low barrier/supportive housing as the most-used form of healthcare (‘attachment variables’). Participants who only accessed healthcare from pharmacies, lab or blood testing, fire or ambulance, incarceration or emergency rooms, or did not access healthcare in the last six months were excluded from the sample. We did not differentiate types of healthcare providers accessed (e.g., a primary care vs. HIV care doctor) because some of the service modalities involve an interdisciplinary workforce. After inspecting the frequency of responses within the attachment variable categories, an ‘attachment to other healthcare provider’ variable was created by combining the following categories: attachment to addiction treatment clinic, a private clinic or doctor, a hospital outpatient unit, and a low threshold service. The reference category for each of these attachment variables included those who reported no attachment to primary care but accessed at least one healthcare type in the past six months.

Data analyses

All variables except for age and ethnicity/ancestry referred to the past six months. All variables were coded as yes vs. no unless otherwise stated. Bivariable and multivariable logistic regression was used to identify factors associated with an unmet healthcare need. To merit inclusion into the multivariable model, explanatory variables had to be associated at the p<0.05 level in bivariable analyses. In sub-analysis, among those who reported an unmet healthcare need, we used the descriptive statistics to explore which specific health issues participants reported not being able to receive care for. We also explored the self-reported reasons for why individuals were not able to receive the care they needed. An open-ended and fixed-answer format question was used to assess which health issues participants report an inability to receive care for. The fixed-answer questions were created based on the focus group discussions with local PWUD communities.²⁵ All p-values were two-sided and statistical analyses were performed using R, version 3.5.0 (R Foundation for Statistical Computing, Vienna, Austria).

RESULTS

In total, 1000 PWUD were recruited to complete the 2GS Supplement, of whom 889 eligible (88.9%) participants were included in these analyses. Among these individuals, 743 (83.6%) reported having an attachment to primary care and 220 (24.7%) reported an unmet healthcare need, as shown in Table 1. The median age of the sample was 50.4 years (Interquartile Range [IQR]: 41.5 – 57.0), with 520 (58.5%) self-identifying as male and 373 (42%) being HIV-positive. Over three quarters (728, 81.9%) reported accessing services or residing in the DTES, while almost half of the sample reported using heroin daily (421, 47.4%) and about a quarter reported using stimulants daily (249, 27.9%).

Table 1.

Bivariable logistic regression analyses of factors associated with an unmet healthcare need among persons who use illicit drugs (n = 889) in Vancouver, British Columbia, December 2017 to November 2018.

Characteristic	Healthcare needs satisfied (%) (n = 669, 75%)	Unmet healthcare need (%) (n = 220, 25%)	Odds Ratio (95% CI)	P Value
Age
Median (IQR)	51 (43–57)	47 (37–56)	—	—
Per year older	—	—	0.97 (0.96 – 0.98)	<0.001
White (vs non-white)	269 (40.2%)	94 (42.7%)	1.11 (0.82 – 1.52)	0.497
Male (vs non-male)	408 (61.0%)	112 (50.9%)	0.63 (0.47 – 0.86)	0.004
UDS positive for fentanyla	277 (48.9%)	103 (58.9%)	1.49 (1.06 – 2.11)	0.022
Daily drug usea
Heroinb	304 (45.4%)	117 (53.2%)	1.85 (1.32 – 2.58)	<0.001
Stimulants, defined as powder or crack cocaine or crystal methamphetamineb	176 (26.3%)	73 (33.2%)	1.39 (1.00 – 1.93)	0.049
HIV	304 (45.4%)	69 (31.4%)	0.55 (0.40 – 0.76)	<0.001
PROMIS Anxiety (Moderate/Severe vs None to Slight/Mild)a	84 (42.42%)	137 (21.99%)	2.61 (1.86 – 3.67)	<0.001
Chronic paina	263 (39.3%)	129 (58.6%)	2.48 (1.79 – 3.46)	<0.001
Homelessa	82 (12.3%)	54 (24.6%)	2.33 (1.58 – 3.41)	<0.001
Incarcerationa	14 (2.1%)	11 (5.0%)	2.46 (1.08 – 5.49)	0.028
Accessing services/Residing in the DTESa	452 (81.0%)	154 (84.6%)	1.12 (0.81 – 1.57)	0.501
Receiving healthcare in one placea	590 (88.2%)	147 (66.8%)	0.27 (0.19 – 0.39)	<0.001
Treated poorly at a healthcare facilitya	85 (12.7%)	119 (54.1%)	8.10 (5.73 – 11.52)	<0.001
Attachment to primary carea	613 (91.6%)	130 (59.1%)	0.10 (0.06 – 0.17)	<0.001
Attachment to primary care ata:
No attachment	23 (3.4%)	44 (20.0%)	reference	—
Integrated care clinic	151 (22.6%)	54 (26.7%)	0.10 (0.05 – 0.19)	<0.001
Community health centre	211 (31.5%)	54 (24.5%)	0.13 (0.07 – 0.24)	<0.001
Otherc	240 (35.9%)	29 (13.2%)	0.12 (0.07 – 0.21)	<0.001

OR: Odds ratio. CI: Confidence interval. UDS: urine drug screen test. PROMIS: Patient-Reported Outcome Measurement Information System. DTES: Downtown Eastside

^aDenotes behaviours and events in the past six months.

^bInjection or non-injection drug use.

^cOther refers to other most frequently accessed healthcare facilities (addiction treatment clinics, private clinic/doctor, hospital outpatient unit, and low threshold services).

In the multivariable model (Table 2), factors positively associated with an unmet healthcare need included: chronic pain (Adjusted Odds Ratio [AOR] = 2.00; 95% CI: 1.30 – 3.01) and being treated poorly at a healthcare facility (AOR = 5.50; 95% CI: 3.59 – 8.60). Receiving healthcare in one place (AOR = 0.42; 95% CI: 0.25 – 0.68) and attachment to primary care at: integrated care clinic (AOR = 0.14; 95% CI: 0.06 – 0.34), community health centre (AOR = 0.23; 95% CI: 0.10 – 0.52), and other healthcare provider (AOR = 0.21; 95% CI: 0.09 – 0.48) were negatively associated with an unmet healthcare need.

Table 2.

Multivariable logistic regression analyses of factors associated with an unmet healthcare need among persons who use illicit drugs (n = 889) in Vancouver, British Columbia, December 2017 to November 2018.

Characteristic	Adjusted OR (95% CI)	P Value
Age
Per year older	0.99 (0.97 – 1.01)	0.171
Male (vs non-male)	0.83 (0.54 – 1.27)	0.994
UDS positive for fentanyla	1.28 (0.73 – 2.23)	0.391
Daily drug usea:
Heroinb	0.88 (0.47 – 1.63)	0.681
Stimulantsb, defined as powder or crack cocaine or crystal methamphetamine	0.94 (0.54 – 1.61)	0.832
HIV	0.71 (0.45 – 1.08)	0.082
PROMIS Anxiety (Mod/Severe vs None to Slight/Mild)a	1.77 (1.12 – 2.76)	0.090
Chronic paina	2.00 (1.30 – 3.01)	0.004
Homelessa	1.77 (1.05 – 3.12)	0.198
Incarcerationa	0.79 (0.27 – 2.29)	0.847
Receiving healthcare in one placea	0.42 (0.25 – 0.68)	0.031
Treated poorly at a healthcare facilitya	5.50 (3.59 – 8.60)	<0.001
Attachment to primary care ata:
No attachment	reference	—
Integrated care clinic	0.14 (0.06 – 0.34)	<0.001
Community health centre	0.23 (0.10 – 0.52)	<0.001
Otherc	0.21 (0.09 – 0.48)	<0.001

OR: Odds ratio. CI: Confidence interval. UDS: urine drug screen test. PROMIS: Patient-Reported Outcome Measurement Information System.

^aDenotes behaviours and events in the past six months

^bInjection or non-injection drug use

^cOther refers to other most frequently accessed healthcare facilities (addiction treatment clinics, private clinic/doctor, hospital outpatient unit, and low threshold services)

To merit inclusion into the final multivariable model, factors must have been associated with the outcome in bivariable analyses at the p <0.05 level.

In sub-analyses, in total, 218 participants provided responses to which health issues they were unable to receive care for. As shown in Table 3, the most frequently reported health issues included: chronic pain (104, 47.7%), dental (65, 29.8%), infection (e.g., pneumonia, infected cut/wound, abscess) (46, 21.1%) and mental health (42, 19.3%). In addition, 180 participants provided reasons for why they could not receive care. As shown in Table 4, the most commonly reported reason was drug use (e.g., fear of discrimination, services withheld) (52, 24.1%), followed by being treated poorly (in a previous visit) (42, 19.4%) and not knowing where to go (36, 16.7%).

Table 3.

Reasons for self-reported health issues individuals were unable to get care for when they needed it (n=218).

Reasons in the past six months	n (%)
Chronic pain	104 (47.7%)
Dental (e.g., tooth decay, mouth sores, gum disease)	65 (29.8%)
Infection (e.g., pneumonia, infected cut or wound, abscess)	46 (21.1%)
Mental health (e.g., anxiety, depression, mood disorder)	42 (19.3%)
Other chronic disease (e.g., diabetes, heart disease, cancer, arthritis)	37 (17.0%)
Infectious disease (e.g., HCV, HIV/AIDS, STIs)	35 (16.1%)
Injury (e.g., broken bone, head injury, wound)	32 (14.7%)
Problematic drug use (e.g., causes problem in your life)	32 (14.7%)
Problematic alcohol use (e.g., causes problem in your life)	11 (5.0%)

Participants could provide more than one response

Problematic alcohol and drug use are self-determined by the participant

Table 4.

Reasons for self-reported why participants could not receive the care they needed (n=180).

Reasons in the past six months	Last 6 months n (%)	Most Common (n%)
My drug use (e.g. Fear of discrimination, services withheld)	52 (24.1%)	40 (22.2%)
Treated poorly (in a previous visit)	42 (19.4%)	32 (17.8%)
Wait time was too long	34 (15.7%)	21 (11.7%)
Didn’t know where to go	36 (16.7%)	20 (11.1%)
Couldn’t afford it	23 (10.6%)	14 (7.8%)
Clinic was closed (permanently or outside hours of operation)	17 (7.9%)	12 (6.7%)
My regular doctor was no longer there/was not in the clinic (e.g. they moved clinics or were on vacation)	20 (9.3%)	12 (6.7%)
Too far/transportation issues	22 (10.2%)	11 (6.1%)
Turned away	31 (14.4%)	10 (5.6%)
Clinic/provider not taking new patients	20 (1.9%)	7 (3.9%)
Don’t have a PHN and/or ID	4 (2.2%)	1 (0.6%)
Police were around the clinic	2 (0.9%)	0 (0.0%)

PHN: Personal Health Number. ID: Identification

Both PHN and ID are needed to access healthcare services in British Columbia, Canada

Participants could provide more than one response for the last six months column, but could provide only one response to the most common column

DISCUSSION

Among our sample of community-recruited PWUD with self-reported healthcare issues, the majority (84%) reported having a regular family doctor or clinic to which they feel comfortable going. Despite this high level of attachment to primary care, about a quarter of the sample reported an unmet healthcare need. We found that participants who reported chronic pain and being treated poorly at a healthcare facility were more likely to report an unmet healthcare need. In contrast, those who reported receiving healthcare in one place and those having attachment to primary care (regardless of healthcare place types) were less likely to report an unmet healthcare need. Chronic pain was the most commonly reported health issue that participants could not receive care for and concerningly, participant’s drug use was the most frequently reported reason for why they could not receive care.

To our knowledge, this is the first study to assess the prevalence of attachment to primary care among PWUD. The high prevalence of attachment to primary care found in our sample is similar to the prevalence in the general Canadian population.³⁰ In 2018, Statistics Canada reported that 85.3% of Canadians had a regular healthcare provider they see or talk to when they need care or advice.³⁰ However, the condition of being comfortable attending the regular care provider was not considered in the study.³⁰ Our finding may reflect the large concentration of low-threshold healthcare services for PWUD and the implementation of the DTES-2GS in our setting.³¹

Although we did not observe a statistically significant link between moderate/severe anxiety and an unmet healthcare need, our sub-analysis results demonstrate that participants frequently report mental health as an issue for which they are unable to receive care. As previously mentioned, treatment for those with mental health and substance use comorbidities has historically been spatially and organizationally separate.^2,5 Our finding may reflect this disconnect in healthcare provisions, specifically fragmentation in care may result in some unmet healthcare needs among PWUD. Treatment at one location requires a diverse workforce, which includes psychiatric personnel (e.g., counsellors and psychiatrists) and additional physical and financial resources.^2,10 To ameliorate the potential disconnect between healthcare providers, an integrated care model approach could be a solution.^2,10,11 In fact, integrated care models are supported by our findings that those who received healthcare in one place and those who had an attachment to integrated care were less likely to have an unmet need for healthcare. For instance, part of the VCH’s mandate for the DTES-2GS is to provide multiple different healthcare services at one location for PWUD.³² One of these integrated care sites includes the Heatley Community Health Centre,³² which offers primary care, mental health, substance use, harm reduction and specialized care (e.g., wound care, palliative care, physiotherapy and occupational therapy) in one location.³² In addition, VCH employs a diverse workforce that includes social workers, counsellors, community liaison workers, psychiatrists, nurses, and physicians, who work together in what are known as an ‘integrated care team’.³² Although the effectiveness of VCH’s DTES-2GS on improving health outcomes for PWUD is yet to be established, the DTES-2GS is in line with past research on integrated models of care.^2,10,11 Future research should continue to examine the effectiveness of the DTES-2GS in addressing unmet healthcare needs among PWUD.

Our findings also indicate that chronic pain is a prominent driver of unmet healthcare needs among our study population. The independent association between having chronic pain and reporting an unmet healthcare need mirrors our sub-analysis finding, where chronic pain was the most commonly reported health issue for which participants could not receive care. Pain management among PWUD has been a well-documented challenge for both healthcare providers and PWUD.^33–37 Among PWUD, undertreated pain and denial of pain medication is commonly reported,^33,36,37 while for healthcare providers, fears of contributing to addiction or relapse are often cited.^34,36 Concerningly, denial of pain medication has been shown to lead to self-managing of pain among PWUD through illicit drug use,^37,38 which contributes to increases in the drug-related morbidity and mortality.^1,2 Our findings support the pre-existing calls for improving pain management among PWUD.^37,38

Notably, the relationship between recent experience of poor treatment at a healthcare facility and an unmet healthcare need was the strongest relationship in our study. Once again, this adjusted association is consistent with our sub-analysis finding, specifically participant’s drug use was the most commonly reported reason for why individuals could not receive care. These findings are also supported by the literature, which highlights that discriminatory practices in healthcare contributes to poorer health outcomes among PWUD.^19–21 A potential measure to reduce discrimination in healthcare settings is to employ staff with lived experience, which some PWUD believe to be a critical component to the healthcare workforce.³⁹ Specifically, these peer support staff members could help reconcile issues surrounding discrimination, as they would be perceived as more ‘credible’.³⁹ Further, peer support groups in addiction treatment have been associated with higher rates of abstinence and satisfaction with treatment among PWUD.³⁹ In addition, improvements in perceived social support and reductions in feelings of guilt/shame were also associated with receiving peer support in addiction treatment among PWUD.³⁹ Therefore, integrated models of care may benefit from including peer support staff within healthcare settings, as they could help foster a comfortable environment for PWUD.³⁹

In sub-analysis, we found that a third of those who reported an unmet healthcare need were not able to receive care for dental care. This finding exemplifies the need to address unmet healthcare needs among PWUD that are not provided for in primary care settings. Specifically, illicit drug use and medications used to treat addiction (e.g., methadone) can result in or exacerbate existing oral health complications among PWUD, including periodontal disease, orofacial injuries (e.g., fractured teeth, tooth loss) and dental pain (e.g., toothaches).⁴⁰ Indeed, oral health issues are among the most prevalent comorbidities related to addiction among PWUD.⁴⁰ Of concern, many PWUD have reported self-management of dental pain through illicit drug use, which can worsen existing health issues and delay appropriate treatment.⁴⁰ Taken together with our findings, there is a need to consider integrating care for oral healthcare among PWUD.^40,41 Although our study was conducted in a Canadian setting with publicly-funded interdisciplinary clinics, a need for an integrated model of care remains pertinent to the US and other healthcare delivery systems that continue to deliver specialized care in organizational silos.

This study has several limitations. As our sample was not randomly recruited, the ability for our results to be generalized to all PWUD is reduced. In addition, many of our measures are self-reported, which may influence the degree of response bias present in our study. However, self-reported measures among PWUD have been shown to be reliable among some PWUD.⁴² Lastly, the cross-sectional nature of this study does not allow us to address the temporal sequence of associations found in our study.

CONCLUSION

This study adds to the current literature by assessing the unmet healthcare needs and attachment to primary care among a large community-recruited sample of PWUD. Notably, we are unaware of any study that has examined the prevalence of attachment to primary care and its association with an unmet healthcare need among PWUD. Our findings indicate that despite a high level of attachment to primary care, roughly one quarter of our sample of PWUD reported an unmet healthcare need. Further, participants who reported receiving healthcare in one place were less likely to report an unmet healthcare need. However, inadequate pain management and stigma and discrimination against PWUD in healthcare settings that were associated with unmet healthcare needs may not be fully addressed through simply integrating the care and would require more specific responses.