Abstract
Abstract
Purpose
The Cohort of Health-Related Outcomes in Chronic Illness Care in General Practice was established using data collected as part of a cluster-randomised trial. This aims to support the trial’s follow-up and enable further examination of the interplay between chronic disease, multimorbidity (MM), polypharmacy (PP) and quality of life (QoL) in a Danish general practice setting.
Participants
The cohort comprises 35 977 adult patients from 250 general practices participating in a cluster-randomised trial and had a response rate of 22.4%. Participants were either registered as chronic care patients or had attended an annual chronic disease consultation. They completed a comprehensive questionnaire on self-reported chronic conditions, medication use, QoL, treatment burden and patient-centred care. Additionally, 431 general practitioners (GPs) from the participating practices completed a questionnaire about managing patients with complex MM.
Findings to date
Among participants, 51.9% were female, the mean age was 65.6 (SD 12.9) years, 93.1% had education beyond basic schooling, and half were retired. Conditions from more than one organ system-based disease group were reported by 82.2%, and 94.6% used one or more prescription medications. The main challenges reported by the participating GPs in managing patients with complex MM were keeping time and obtaining an overview of the patient’s health status.
Future plans
Cohort data will be linked with Danish registries to improve the detection and treatment of chronic conditions and PP in general practice.
Registration
The cluster randomised trial (MM600) is registered with ClinicalTrials.gov ID: NCT05676541.
Keywords: Quality of Life, EPIDEMIOLOGIC STUDIES, Multimorbidity, Primary Health Care, General Practice
STRENGTHS AND LIMITATIONS OF THIS STUDY.
This cohort contains patient- and general practitioner-reported data, which supplements routinely collected data from the Danish primary healthcare sector.
The cohort is based on contact information for all chronic care patients from 250 Danish general practices.
Information on quality of life is obtained with a novel questionnaire (MultiMorbidity Questionnaire 1)—specifically developed and validated for patients with multimorbidity.
The questionnaire length and online distribution method may lead to underrepresentation and low completion rates by the most vulnerable patients.
Self-reported conditions with low symptom burden may be underrepresented.
Introduction
The prevalence of multimorbidity (MM), defined as having two or more chronic conditions, is increasing among patients of all ages.1 2 MM is more common in older people, among women and in people with lower socioeconomic status.3 It is often accompanied by polypharmacy (PP) and is associated with increased mortality, high treatment burden and impaired quality of life (QoL).4,7 Treatment burden is defined as the work that patients must do to manage their conditions, stressors that exacerbate the experienced burden and the impact of the burden, for example, remembering healthcare appointments, taking medication and monitoring health.4 8
The coexistence of two or more chronic conditions is the most common definition of MM; however, other definitions have been suggested to identify patients with the most complex MM.9 A Danish study defined MM based on groups of diagnoses instead of summing up single diagnoses. In that study, to define MM, one diagnosis from at least two different groups of diagnoses (based on the International Classification of Diseases, 10th version) was required to have MM. By grouping diagnoses with similarities in treatment, management and organisation, the authors claim that the definition can potentially mirror some of the complexity embedded in MM.5
General practitioners (GPs) with a high proportion of patients with MM are at risk of negative emotional impact, which can lead to burnout.10 11 Treatment is complicated by the limitations of single-disease guidelines, and lack of time is described as a barrier to shared decision-making and patient-centred care.12 Even though patient-centred care is essential in high-value care, it is often reported as lacking by patients with MM.4 13 A randomised controlled trial (RCT) in primary care shows that using a patient-centred structure increases patient-centredness in MM management.14
Earlier cohort studies have documented the inverse association between MM and QoL.6 It has been investigated whether extended, comprehensive consultations can benefit patients with MM, but limited effectiveness was observed.14 15 A possible explanation for the lack of effectiveness can be the choice of patient-reported outcome measures (PROMs), such as EuroQol-5 Domain (EQ-5D) and 36-Item Short Form Survey.16 These are generic and not disease-specific and might be limited by low responsiveness.17 A disease-specific PROM, such as the MultiMorbidity Questionnaire 1 (MMQ1), developed specifically to measure needs-based QoL in patients with MM, may be more suitable to measure the challenges experienced by patients with MM and was used in this cohort.18 19
In 2023, the MM600 trial investigating extended consultation for patients with MM was initiated in 250 Danish general practices.20 The Cohort of Health-Related Outcomes in Chronic Illness Care in General Practice (CHRONIC-GP) was established in conjunction with the trial and comprises three surveys conducted over a 2-year period. It measures patient-reported outcomes and experiences of people living with chronic disease and MM, aiming to examine healthcare utilisation and trajectories of patients with chronic conditions. Besides data on patients, it also contains data on GPs and their experiences of working with patients who have complex MM. As an addition to earlier cohorts established alongside trials, this cohort contains three new PROMs on needs-based QoL, patient-centredness in consultations and treatment burden.14 15 18 21 22 In addition, the cohort provided longitudinal information on the GPs’ experiences with managing MM.
This study describes the methods and presents baseline results of the CHRONIC-GP.
Cohort description
Study design
This cohort profile describes the longitudinal, survey-based CHRONIC-GP conducted in connection with a pragmatic, cluster-randomised controlled trial (cRCT) in 250 Danish general practices, the MM600 trial.20
Setting and population
Participating practices and general practitioners
Practices for the MM600 trial were recruited through their quality cluster coordinators. Ninety-six per cent of general practices are affiliated with a quality cluster, each coordinated by a GP. Danish GPs work mostly as fee-for-service. They can allocate additional time to perform a yearly check-up for most chronic conditions, besides patients with chronic obstructive pulmonary disease or diabetes, who must be listed as chronic-care patients. They agreed to participate in a trial where the intervention practices can offer a reimbursed extended consultation for patients with complex MM in 2023 and 2024. GPs in both control and intervention practices agreed to complete a yearly questionnaire, for which they were compensated for their time. Practices were recruited in September 2022. The trial procedures are described in more detail in the trial protocol.20
Patient population and timeline for data collection
In connection with the trial, a questionnaire was sent to all patients meeting the eligibility criteria:
Adults (18 years or older), AND
Either listed as a chronic-care patient or having attended at least one annual chronic disease consultation in the year 2022, AND
Listed in a practice participating in the MM600 trial on 1 January 2023.
In Denmark, it is possible to identify Danish citizens based on predefined criteria and to invite them to participate in research projects. Patients were identified through the Danish Health Data Authority and contacted via secure electronic email. In March 2023, online questionnaires were sent to all eligible patients via a secure online connection linked to their civil registration numbers.23 All online questionnaires were collected up to the end of May 2023. An English translation of the contact letters can be seen in online supplemental appendix 1.
Online secure surveys are cheaper and more feasible for some patients, and most Danish citizens can access secure online email. However, some patient groups may be under-represented. To be able to weigh our results to represent underrepresented groups, postal questionnaires were sent to a randomly selected group of 1000 patients without electronic secure email (figure 1). Postal questionnaires were distributed in June 2023. Furthermore, in April and May 2023, a randomly selected group of 1996 who did not respond to the first digital invitation received an electronic reminder to participate in the questionnaire survey (figure 1). We sent the reminder to a random subgroup to minimise the number of reminders for the target population, but still be able to adjust our results for differences in respondents to the first contact and the reminder.
Figure 1. Patient inclusion. CPR, Det Centrale Personregister (Eng: personal identification number); GP, general practitioner; SDS, Sundhedsdatastyrelsen (Eng: Danish Health Data Authority).
In connection with the trial, GPs identified and enrolled an additional group of patients with complex MM, whom the Danish Health Data Authority did not necessarily identify, and these patients were added to the cohort (figure 1). To have complex MM, the patient should be an adult, have at least two chronic conditions and experience major challenges with their life due to MM.
A follow-up questionnaire was conducted in March 2024 and in March 2025. This study describes the results of the first data collection in 2023.
Survey data will be uploaded to the encrypted study server at Statistics Denmark and linked to registry data on patient demographics, socioeconomic status, work affiliation, healthcare utilisation, hospitalisation, diagnoses in the secondary sector and redeemed prescription medicines from Danish registries. At linkage, the data are pseudo-anonymised. In Denmark, uploading personal data to the registries corresponds to anonymisation, since identification of individuals in these registries is prohibited.
In addition to the patient questionnaire, all participating GPs received an online questionnaire in late 2022, including questions about the practice’s organisation and the perceived burden of managing patients with MM.
Variables
Design of the patient survey
The patient survey consisted of five parts to capture the different aspects of living with chronic disease and MM. Parts 1 and 5 were tested in 12 individual interviews with patients with MM recruited from general practice. The interviews aimed to ensure understandability and functionality, and to correct minor errors. The remaining three parts consisted of PROMs, which underwent a more comprehensive content validation procedure.22
Sex and age were determined by the participant’s civil registration number at inclusion. Further gender constructs were not measured.
The first part of the survey was ‘Questions about your health’. The questions in this part were inspired by, but not identical to, a large, Danish yearly survey regarding the general health of the Danish population.24 The two initial questions were perceived well-being and use of medication. Perceived well-being was measured as a global item: ‘How do you feel?’ with five response options: ‘Very good’, ‘Good’, ‘Fair’, ‘Bad’ or ‘Very bad’. To assess medication use, participants responded to: ‘Do you take any prescription medicine as prescribed by a doctor?’ with four response categories.
The remaining 13 questions in ‘Questions about your health’ regarded chronic conditions that the participants believed they suffered from. The conditions were mostly grouped after organ systems, but after testing the groupings in patient interviews, some of the groups were altered. The resulting groups were: ‘cancer’, ‘diabetes’, ‘allergies’, ‘thyroid disease’, ‘a disease of the brain or nervous system’, ‘a respiratory disease’, ‘a disease of the heart or blood vessels’, ‘a disease in the stomach or intestines’, ‘a disease in the urinary tract or genitals’, ‘a disease in the muscles, joints or skeleton’, ‘a mental disease’, ‘a skin disease’ and ‘a disease that affects vision or hearing’. Common examples followed all groups. The patients were asked if they had ever had the disease(s) in question, for example: ‘Have you ever had a respiratory disease?’ with the possibility to answer: ‘No, I have never had that’, ‘Yes, and I still have it’, ‘Yes, but I no longer have it’ and ‘Don’t know’. In case respondents answered ‘Yes, but I no longer have it’, a second option opened where they could answer whether they still had symptoms or long-term effects or were still taking medication for the condition. In this way, if participants reported two or more conditions from the same disease group, they were counted as one.
Finally, participants who answered yes to: ‘Have you had other long-term illnesses?’ could write a comment and list any conditions they felt were not covered in the groups. All comments were manually reviewed by a final-year medical student and allocated to one of the groups above.
Respondents who did not report any long-term conditions and did not report any medication were offered the option to opt out before the second part of the questionnaire.
The second part of the questionnaire consisted of the MMQ1. The MMQ1 is a validated MM-specific PROM to measure needs-based QoL in patients with MM.18 19 The PROM assesses the six domains: Physical ability, Worries, Limitations in everyday life, Social life, Self-image and Economy of needs-based QoL.
The third and fourth parts of the questionnaire were optional. The third part of the questionnaire consisted of the MMQ1 Treatment Burden (MMQ1-TB). The MMQ1-TB is a newly developed scoring tool that addresses the six domains: Information about my treatments, Challenges with medicines, Medical appointments, Challenges in contact with the health system, Self-monitoring and Health behaviour of treatment burden in patients with MM. Like other PROMs, it measures treatment burden but has been specifically developed to supplement MMQ1 without redundant questions.25 26 Results from its development and validation have been published.21
The fourth part of the patient questionnaire consists of a part on the participants’ most recent consultation with their GPs regarding their long-term conditions and a part with a measurement tool on patient-centred care: The Patient-Centredness in Consultations PROM. The general questions about the consultation on long-term conditions concerned type of consultation, time and participants. Based on the findings by Mead and Bower and later modifications by Langberg et al, the Patient-Centredness in Consultations PROM measures five domains: Biopsychosocial perspective, Patient-as-person, Sharing power and responsibility, Therapeutic alliance and Coordinated care.13 27 The PROM comprises 25 items and three additional items if the patient was referred to further treatment after the consultation. The development and validation of the PROM has been published.22
The fifth part of the patient questionnaire included sociodemographic questions inspired by those of the previously mentioned Danish national survey regarding the population’s health.24 The sociodemographic variables included geographical region, postal code, information on whether they lived alone, information on schooling/youth education, further education, if the participant was currently being educated and if the participant was currently working. Please refer to online supplemental appendix 2 for the list of variables and response categories.
Practices
The survey among the 495 participating GPs from the 250 participating practices was divided into (1) a part about their practices, which was only answered by the practice coordinator for the trial, and (2) a part for all participating GPs.
The coordinators from each practice provided information about their practice type, number of owners, standardised full-time positions and recent MM training.
Regarding the practice type, practice coordinators were asked to identify the type of practice between the following options: ‘Single-handed practice’, ‘Group practice’ or ‘Other’, and if the practice cooperated with other practices or worked alone. Afterwards, the practice coordinator filled out the number of owners and how many full-time positions their practice was standardised for. Finally, participants were asked whether their practice had received additional MM management training within the past 2 years.
General practitioners
Data on GPs participating includes variables on their connection to practice, years as a GP, time in current practice and information on the experienced challenges in working with patients with complex MM.
GPs from participating practices were asked to describe their connection to their current practice from one of the listed response options: ‘Owner’, ‘Temp’, ‘Permanently employed’ or ‘Other’. Participating GPs filled in the year of finalising specialty training and the year they started working in their current practices.
The GPs’ challenges working with patients with complex MM were measured using six questions. The questions were based on the findings from qualitative work in the field and were tested for comprehensibility in two cognitive interviews with GPs.12 The GPs were asked to indicate the frequency with which they encountered specific challenges, using the following response options: ‘No, not at all’, ‘Yes, a few times’, ‘Yes, sometimes’ and ‘Yes, many times’. The specific challenges included: ‘I find it difficult to get an overview of the overall health when the patient has complex multimorbidity’, ‘It is difficult for me to keep to the time in consultations with patients with complex multimorbidity’, ‘I find it difficult to get help from other specialists about patients with complex multimorbidity’, ‘I find it difficult to prioritise between different treatments when the patient has complex multimorbidity’, ‘I find it difficult to conduct a medication review when the patient has complex multimorbidity’ and ‘It helps me to include the patient’s wishes when I have to prioritise between different treatments when the patient has complex multimorbidity’. The definition of complex MM is found in the MM600 protocol and the list of variables in online supplemental appendix 3.20
Statistical methods
The statistics in this protocol and the presentation of baseline results are descriptive. Variables in the patient survey are presented as frequencies or means and SD. Variables in the surveys on GPs and practices are presented as frequencies or medians and IQRs. Categorical and binary data are presented as frequencies.
The statistical software R V.4.3.2 (2023-10-31 ucrt) was used for all computations.28
Ethics
All participants were informed about their rights before initiation of the questionnaire, including the right not to participate or withdraw from the survey at any time without sanctions. The contact and information letter is included in online supplemental appendix 1. According to Section 2 of the Danish Act on Research Ethics of Research Projects, questionnaire studies are not regarded as health research projects but as quality improvement projects. The CHRONIC-GP study was presented to the Ethical Committee of the Capital Region of Denmark, who confirmed the study was a quality improvement project that does not require ethical oversight (ref: H-22041229 (cRCT) and F-24026474 (CHRONIC-GP)). Contact data on the participating patients through the Danish Health Data Authority followed the Order on Sharing of Personal Information, Section 10, Subsections 1 and 2 of the Danish Data Protection Act.
Data management
Data are stored on encrypted servers with logging following the data policy of the University of Copenhagen. Data from Danish registers are stored on servers by Statistics Denmark and only accessed by two-factor authentication. For the analysis, patient ID and practice ID were pseudonymised so neither patient ID nor practice ID was visible to the researchers. We comply with the General Data Protection Regulation.
Patient and public involvement
Patients were not involved in the conception of the study or the interpretation of results. We conducted interviews with patients in the development of the questionnaire to ensure understanding, functionality and, for the PROMs, comprehensibility.
Bias
Selection bias in the cohort may arise from differences between participating and non-participating practices and the accompanying patients, which cannot be avoided in a cRCT. Respondents may not represent the full population due to factors like severe illness, impaired physical ability, reading disabilities and language barriers, which are difficult to avoid in MM research.
The inevitable information bias that comes with questionnaires has been partly accommodated by using PROMs that have been validated and were developed for patients with chronic conditions.
Confounding bias is not a concern in this report since only descriptive statistics were presented, but it should be considered in future studies. Despite precautions, academic and confirmation biases may still occur. Reporting bias is not anticipated.
Findings to date
Patient questionnaires
Meeting the cohort inclusion criteria, 182 891 were identified by The Danish Health Data Authority (figure 1). In total, 2179 patients were identified by their GPs as eligible for the MM600 trial. Of the GP-identified patients, 477 were unique patients not previously identified by The Danish Health Data Authority and thus added to the CHRONIC-GP.20 The GPs marked 424 eligible patients who should not receive a questionnaire (for unknown reasons) and thus were excluded from the cohort. Four patients identified by their GPs were excluded because the GP had mistyped their identification number.
Of the total population of 183 061 people, 159 619 had online secure mail and received the questionnaire digitally. Of the 23 442 people with no secure online mail, we randomly selected 1000 participants and applied for postal addresses. Postal questionnaires were sent to 965 people still listed in The Danish Health Data Authority by the time of application.
In total, 35 977 responded to the questionnaire; 35 620 to the first online version, 241 to the online reminder and 116 to the postal version. The comparison between respondents and non-respondents concerning age and sex has been previously published.22 The response rates were generally better in the older age groups than in younger ones, with no pronounced difference between male and female respondents.
The differences between the respondents to the first online questionnaire, the online reminder and the postal questionnaire are shown in table 1.
Table 1. Patient characteristics.
| Variable | N | Overall, n=35 977 | First online questionnaire, n=35 620 | Online reminder,* n=241 | Postal questionnaire,† n=116 |
|---|---|---|---|---|---|
| Female sex, n (%) | 35 977 | 18 665 (51.9%) | 18 458 (51.8%) | 137 (56.8%) | 70 (60.3%) |
| Age, n (%) | 35 977 | ||||
| 18–39 years | 1595 (4.4%) | 1579 (4.4%) | 15 (6.2%) | <5‡ | |
| 40–49 years | 2263 (6.3%) | 2237 (6.3%) | 24 (10.0%) | <5‡ | |
| 50–59 years | 6045 (16.8%) | 5997 (16.8%) | 45 (18.7%) | <5‡ | |
| 60–69 years | 10 499 (29.2%) | 10 408 (29.2%) | 71 (29.5%) | 20 (17.2%) | |
| 70–79 years | 11 766 (32.7%) | 11 665 (32.7%) | 65 (27.0%) | 36 (31.0%) | |
| 80+years | 3809 (10.6%) | 3734 (10.5%) | 21 (8.7%) | 54 (46.6%) | |
| Education level, n (%) | 33 068 | ||||
| Basic schooling | 2289 (6.9%) | 2244 (6.8%) | 17 (8.3%) | 28 (29.2%) | |
| High school or courses | 15 166 (45.9%) | 15 023 (45.8%) | 89 (43.6%) | 54 (56.3%) | |
| College or university | 15 613 (47.2%) | 15 501 (47.3%) | 98 (48.0%) | 14 (14.6%) | |
| Missing | 2909 | 2852 | 37 | 20 | |
| Occupation, n (%) | 33 067 | ||||
| Not working and not studying | 5039 (15.2%) | 4987 (15.2%) | 36 (17.6%) | 16 (16.5%) | |
| Working or studying | 11 453 (34.6%) | 11 364 (34.7%) | 85 (41.7%) | 4 (4.1%) | |
| Retired | 16 575 (50.1%) | 16 415 (50.1%) | 83 (40.7%) | 77 (79.4%) | |
| Missing | 2910 | 2854 | 37 | 19 | |
| Living alone, n (%) | 33 095 | 9051 (27.3%) | 8941 (27.3%) | 53 (26.0%) | 57 (56.4%) |
| Missing | 2882 | 2830 | 37 | 15 | |
| Self-reported disease groups, n (%) | 35 459 | ||||
| 0–1 | 7851 (22.1%) | 7792 (22.2%) | 40 (17.2%) | 19 (19.0%) | |
| 2–3 | 15 672 (44.2%) | 15 531 (44.2%) | 104 (44.6%) | 37 (37.0%) | |
| 4–5 | 9058 (25.5%) | 8966 (25.5%) | 63 (27.0%) | 29 (29.0%) | |
| 6–7 | 2485 (7.0%) | 2456 (7.0%) | 19 (8.2%) | 10 (10.0%) | |
| 8–9 | 393 (1.1%) | 381 (1.1%) | 7 (3.0%) | 5 (5.0%) | |
| Missing | 518 | 494 | 8 | 16 | |
| Do you take any prescription medicine as prescribed by a doctor?, n (%) | 35 841 | ||||
| None | 1923 (5.4%) | 1902 (5.4%) | 17 (7.1%) | 4 (3.4%) | |
| 1–4 | 23 333 (65.1%) | 23 122 (65.2%) | 158 (65.8%) | 53 (45.7%) | |
| 5–8 | 8614 (24.0%) | 8519 (24.0%) | 52 (21.7%) | 43 (37.1%) | |
| >8 | 1971 (5.5%) | 1942 (5.5%) | 13 (5.4%) | 16 (13.8%) | |
| Missing | 136 | 135 | 1 | 0 | |
| How do you feel?, n (%) | 35 977 | ||||
| Very good | 7888 (21.9%) | 7832 (22.0%) | 46 (19.1%) | Masked§ | |
| Good | 13 496 (37.5%) | 13 369 (37.5%) | 90 (37.3%) | 37 (31.9%) | |
| Fair | 11 366 (31.6%) | 11 234 (31.5%) | 77 (32.0%) | 55 (47.4%) | |
| Bad | 2775 (7.7%) | 2739 (7.7%) | Masked§ | 11 (9.5%) | |
| Very bad | 452 (1.3%) | 446 (1.3%) | <5‡ | <5‡ |
Out of 1996 randomly selected non-respondents.
Out of 965 randomly selected patients.
Masked due to small numbers.
Masked to prevent small numbers from being calculated.
N, Number of respondents answering the specific part.
Of the respondents, 52% (n=18 665) were female (table 1). One-third of the respondents were 70–79 years old, and an additional third were aged 60–69 years. The age distribution differed between the three questionnaire groups, with the reminder group being the youngest and the postal group being the oldest, with 47% of the postal respondents aged 80 years or older. The mean age was 65.6 (SD 12.9) years.
Regarding education, 93% of the participants had completed some education beyond basic schooling, and 47% (n=15 613) had completed college or university. The distribution of educational level was similar between the three questionnaires, except for the postal questionnaire, in which 29% had basic schooling only.
Forty-four per cent of the respondents reported having chronic conditions from two or three different organ system-based disease groups, for example, heart diseases and musculoskeletal diseases. The mean number of reported conditions was 2.9 (SD 1.7). Twenty-two per cent reported one or no chronic conditions, and 26% reported having chronic conditions from three or four groups. Eight per cent of the respondents had chronic conditions from five or more groups, for example, endocrinological disease, heart disease, musculoskeletal disease, impaired senses and cancer. The distribution of the number of chronic conditions was similar between the three questionnaires.
Sixty-five per cent reported taking 1–4 prescribed medicines, and 5.4% reported not taking medicine. The postal group reported taking more prescription medicine than the other groups.
Regarding self-perceived health status, 22% (n=7888) of the total sample reported feeling ‘Very good’. This variable varied between the groups, with fewer postal respondents feeling very good.
Response and completion rates
Table 2 displays response rates of the five-part patient questionnaire and the drop-off. The completion rate of the complete patient questionnaire was 20.6%, which is almost the response rate (22.4%). Among the participants who began the questionnaire, the lowest completion rates were observed among the postal participants, and the greatest completion rate was among respondents to the first online questionnaire.
Table 2. Completion rates.
| Way of participation | Initiated survey | Survey part 1, questions about health, n (%) | Survey part 2, n (%) | Survey part 3,* n (%) (voluntary) | Survey part 4,* n (%) (voluntary) | Complete survey, n (%) |
|---|---|---|---|---|---|---|
| Total | 35 977 | 35 459 (98.6) | 33 799 (93.9) | 28 476 (99.1) | 23 860 (99.2) | 33 068 (91.9) |
| First online questionnaire | 35 620 | 35 126 (98.6) | 33 485 (94.0) | 28 226 (99.2) | 23 663 (99.2) | 32 766 (92.0) |
| Online reminder | 241 | 233 (96.7) | 214 (88.8) | 160 (97.0) | 132 (97.8) | 204 (84.6) |
| Postal questionnaire | 116 | 100 (86.2) | 100 (86.2) | 90 (94.7) | 65 (92.9) | 98 (84.5) |
The table shows the completion rates of participants who started the questionnaire.
Participants could skip parts 3 and 4 if deemed irrelevant. Frequencies in parts 3 and 4 are compared with the number of participants who opened the respective questionnaires.
Practice and GP questionnaires
250 practices participated in the trial, and 241 practice coordinators responded to the practice questionnaire. Information on standardised full-time positions among participating practices indicates a trend towards smaller practice sizes. Single-handed practices accounted for 32% (n=77) and practices with two affiliated 28% (n=68). Practices with three full-time GPs counted 19% (n=46), and practices with four full-time GPs 14% (n=33). Practices standardised for five, six and eight full-time positions are less common, reported by 5.0% (n=12), 1.7% (n=4) and 0.4% (n=1) of the practice coordinators, respectively. Forty-seven per cent (n=118) of the practice coordinators replied that their practice had not received additional training on MM in the past 2 years.
Of the 495 GPs who signed up for the MM600 trial, 431 responded to the GP questionnaire regarding their affiliation with the practice. Most respondents were practice owners (n=418, 97%), 8 (1.9%) permanently employed, 3 (0.7%) temps and 2 (0.5%) characterised themselves as having other connections to practice. They had a median (IQR) experience as specialists of 12 (6; 18) years (n=495) and reported a median (IQR) affiliation with their current practices of 9 (4; 17) years (n=432).
All GPs were asked about their challenges in managing patients with complex MM. The results are presented in figure 2. Time management during consultations posed a considerable challenge to almost all participating GPs (figure 2). Of the respondents, 99% (n=424) frequently, sometimes or occasionally found it difficult to adhere to scheduled times. Only five GPs did not find it difficult. Almost all respondents (n=423, 99%) reported difficulties in gaining a comprehensive overview of the overall health status of patients with complex MM, with just six participants not reporting challenges. Prioritising treatments when the patient has complex MM was difficult for 94% (n=403) of the participants. Conversely, 6.1% (n=26) of the GPs reported no difficulties. Conducting medication reviews for patients with complex MM is challenging and reported as difficult by 90% (n=388) of the participating GPs. Only 9.6% (n=41) did not report any difficulties. Collaborative challenges with other specialists are evident, with only 11% (n=49) never facing challenges. It was reported as challenging, at least a few times, by 380 (89%) of the GPs. Including patients’ wishes in treatment prioritisation was found helpful by 98% (n=419) of the participating GPs. Only 2.3% (n=10) did not find it helpful at all.
Figure 2. General practitioners’ (GPs’) challenges and strategies in the management of patients with complex multimorbidity. The full statements are found in the ‘Variables’ section.
Summary of findings to date
This article presents the nation-wide CHRONIC-GP, a new cohort of 35 977 patients developed to support follow-up from a cluster-randomised trial and to facilitate further research on chronic conditions. The patients were sampled from the 250 practices participating in the cRCT. Participants either attended at least one chronic disease consultation in general practice in 2022 or were listed as chronic-care patients. Regarding patient volume, the participating practices were slightly larger than the average Danish general practice, but otherwise representative of Danish general practices.29
The survey consisted of five sections with different focuses, containing questions for patients living with chronic conditions and MM: (1) self-reported chronic conditions and medicine use, (2) the MMQ1 PROM, measuring the needs-based QoL, (3) the MMQ1-TB measuring treatment burden (voluntary questions), (4) the patient-centred care PROM, measuring patient-centredness in chronic disease consultations (voluntary questions) and (5) sociodemographic questions.
The cohort mainly consists of adult patients with chronic conditions and MM with some education beyond basic schooling. A supplementary online reminder was sent to non-respondents, and a postal survey was sent to people without secure email to increase response rates. The respondents in the reminder cohort were younger than the initial respondents, and the postal survey respondents were older and had shorter educations. The total completion rate was 20.6% with a low dropout.
In addition, GPs received questions regarding their experiences working with patients with complex MM, and the results point out that the work is difficult for the GPs.
Comparison to existing literature
To our knowledge, two similar cohorts on patients with chronic conditions and MM derived from cRCTs in the UK, the 3D Study and the CARE Plus Study, exist.14 15 While the 3D Study included people of all ages, the CARE Plus Study solely included people aged 30–65 years from highly deprived areas. Furthermore, the two cohorts contain fewer patients, 1546 and 152, respectively, compared with the CHRONIC-GP (n=35 977).
While QoL was the main outcome of all cohorts, 3D and CARE Plus used a generic questionnaire on health-related QoL (EQ-5D-5L).30 On the other hand, the CHRONIC-GP assessed needs-based QoL using the MMQ1, developed and validated on patients with MM. In contrast to CARE Plus, the 3D Study and the CHRONIC-GP measured TB and patient-centred care.
CARE Plus included patients with two or more chronic conditions, not further specifying what type of condition. Both the CHRONIC-GP and the 3D Study used modified disease definitions, that is, diseases are included as groups defined by similarities in terms of aetiology or management. Instead of diseases, the number of affected groups was counted. The 3D Study included patients with diseases from three or more groups, while the CHRONIC-GP included patients suspected of having a disease.
Despite only the suspicion of one condition being needed to be invited to the CHRONIC-GP, 82.8% reported conditions from more than one disease group. Earlier studies found disease accumulation—the fact that one condition is often followed by others—possibly explaining the high prevalence of MM.31 32 Most CHRONIC-GP participants were younger than 70 years, which is in line with recent literature noticing the highest actual numbers of long-term conditions among people <65 years.17
In line with earlier studies, almost all participating GPs described challenges managing patients with complex MM.33 However, almost every participating GP reported more ease in prioritising treatments when including patient wishes.
Strengths and limitations
Several strengths apply to the study cohort. The cohort contains information on patient-reported diseases and three PROMs. Furthermore, the participants represent chronic care patients from a nationwide sample of practices. In addition, the small number of incomplete questionnaires should also be mentioned.
Acknowledgeable limitations also apply. First, selection bias is present due to the way of inclusion of practices in the cluster-randomised trial. Practices managed by the regions instead of by GPs, especially frequent in deprived regions with doctor shortages, could not participate in the cluster-randomised trial. However, they account for less than 5% of the total number of general practices in Denmark.34 Also, practices are more likely to participate if the research is locally relevant or clinically important, resulting in a response bias.35 On the other hand, practices highly burdened by complex patients and social disadvantages might not be able to participate in a trial.36 37 Second, the selection of patients within the practices may introduce bias, since the eligibility criteria entail a selection bias due to disease prevalence. In general practice, annual check-ups for chronic diseases are conducted systematically, to a higher or lesser degree, depending on the specific practice and condition.38 Diagnoses, such as diabetes and chronic obstructive pulmonary disease, that are more systematically checked at annual chronic disease consultations will perhaps be relatively more frequent in the cohort. Diagnoses that are generally underdiagnosed in the population are naturally underrepresented in the CHRONIC-GP; however, this is not unique to this cohort. Due to the method of inclusion, there is also a risk of false eligibility, that is, the GP codes an annual check-up for a suspected chronic condition (thereby making a patient eligible) for a patient who is not diseased. In this case, not responding to the survey is correct behaviour, since the patient is not within the target population, but the response rate is falsely lowered. Third, respondents are probably not representative of the full population due to several factors. Patients with severe illnesses and impaired physical abilities may not participate due to practical challenges in visiting their GPs and filling out questionnaires. Likewise, the length of the questionnaire might underrepresent patients with less time, for example, due to work, education, family, high treatment burden, vulnerable patients, etc. Since the questionnaire is only available in Danish, non-Danish-speaking citizens are not represented. Fourth, information bias, more specifically differential misclassification, is suspected in the reporting of conditions and medications; patients with well-treated conditions or conditions with a low symptom burden may think of themselves as non-diseased. Furthermore, recall bias on self-reported information probably underestimates the prevalence of several conditions and information on patient-centredness.39 Regarding medicine use, a greater inaccuracy in reporting among patients consuming many medications versus patients using few medications seems intuitive.
Conclusion
The CHRONIC-GP contains comprehensive data on patient-reported information about living with chronic disease and MM in a Danish general practice setting. Findings from the nation-wide, real-world cohort offer a unique opportunity to understand the interplay between chronic conditions, PP and QoL. Merging the patient-reported data with data from Danish registers makes it possible to study general associations and trends in the Danish population, eventually leading to better detection and treatment of patients with chronic disease in general practice. Finally, the GP-reported data help to clarify difficulties in working with these patients.
Further details
Collaboration
The real-world cRCT-based CHRONIC-GP contains loads of patient-reported information on chronic diseases and QoL, which is highly valuable, and none like in a Danish general practice setting. The cohort will increase the understanding of the interplay between chronic conditions, PP and QoL among patients visiting their GP for annual check-ups. Later, the CHRONIC-GP is merged with the nationwide Danish registers on diagnoses, medications and socioeconomic factors, using novel insights into patients’ understanding of their health. This is unique, compared with the other trial-based cohorts, and may lead to improved care. Finally, we will be able to research the characteristics of non-respondents.
For collaboration inquiries, please contact the corresponding author. We welcome collaboration with researchers from secondary care and other research institutions, both within and outside Denmark, and we are happy to share experiences with researchers from other countries building similar cohorts.
Supplementary material
Acknowledgements
We would like to thank the full MM600 project team for their contributions in the design and conduction of the trial: Anders Prior, Anders Stockmar, Ann Dorrit Guassora, Anna Bernhardt Lyhnebeck, Anne Frølich, Anne Holm, Anne Møller, Ann-Kathrin Lindahl Christiansen, Barbara Ann Barret, Camilla Merrild, Elisabeth Søndergaard, Frans Waldorff, Henrik Larsen, Iben Charlotte Aaman, Janus Laust Thomsen, Jens Søndergård, Jesper Bo Nielsen, Jette Kolding Kristensen, John Brandt Brodersen, John Sahl Andersen, Katrine Tranberg Jensen, Kristine Bissenbacker, Line Bjørnskov Pedersen, Mads Aage Toft Kristensen, Maria Haahr Nielsen, Marius Brostrøm Kousgaard, Mette Bech Risør, Maarten Pieter Rozing, Per Kallestrup, Sanne Lykke Lundstrøm, Sidsel Böcher, Sofie Rosenlund Lau, Susanne Reventlow, Sussi Friis Buhl, Tora Grauers Willadsen, Volkert Siersma and Zaza Kamper-Jørgensen.
Footnotes
Funding: The project is supported by the public agreement between the Danish Regions and the General Practitioners’ Organization 2022–2024, ‘Fonden for Almen Praksis’ and ‘Lilly & Herbert Hansens Fond’. The funders had no role in study design, data collection, data management, data analysis, interpretation or the decision to submit the study.
Prepublication history and additional supplemental material for this paper are available online. To view these files, please visit the journal online (https://doi.org/10.1136/bmjopen-2025-103807).
Provenance and peer review: Not commissioned; externally peer reviewed.
Patient consent for publication: Not applicable.
Ethics approval: This study involves human participants but Capital Region’s Ethical Committee ref: H-22041229 and F-24026474 exempted this study. Participants gave informed consent to participate in the study before taking part.
Data availability free text: The datasets generated during the current study are not publicly available due to individual privacy. Anonymised or aggregated datasets can under some circumstances be made available from the corresponding author upon reasonable request. After completion of the trial, the data will be merged with Danish registries. Data merged with Danish registers is securely stored on encrypted servers at Statistics Denmark with logging and may only be accessed by two-factor authentication. It is legally prohibited to export and share this data.
Patient and public involvement: Patients and/or the public were not involved in the design, or conduct, or reporting or dissemination plans of this research.
Data availability statement
Data may be obtained from a third party and are not publicly available.
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