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Optimizing Study Design for Evaluating Complex Interventions: An Example of a Feasibility Study in Person-Centered and Integrated Chronic Disease Care in Dutch General Practice Cover

Optimizing Study Design for Evaluating Complex Interventions: An Example of a Feasibility Study in Person-Centered and Integrated Chronic Disease Care in Dutch General Practice

Open Access
|Nov 2025

Figures & Tables

ijic-25-4-8998-g1.png
Figure 1

Schematic representation of the Person-Centred and Integrated Care (PC-IC) approach* [2] for the management of patients with chronic diseases and multimorbidity in primary care.

* In Step 1 and Step 2 of the PC-IC approach, the Positive Health Tool was implemented. It encompasses six domains: bodily functions, mental and emotional well-being, meaningfulness, quality of life, social well-being/participation, and daily functioning. (4) In Step 1, the patient prepares for the consultation with the healthcare professional by answering questions, preferably digitally. The answers to the questions result in a visual aid (‘Spider Web’), for the discussion between patient and healthcare professional (Step 2). In consultation with the healthcare professional, the patient decides which domain has priority and which personal (health) goals he wants to achieve (Step 3). The healthcare professional discusses with the patient which treatments and support are most suitable for the patient (Step 4) and records the health goals and the chosen treatments (interventions) in a digitalized individual care plan (Step 5) that can be shared with other care providers involved. In Step 6, the selected treatments and other support takes place, after or during which one or more (interim) evaluation visits can be planned, depending on the patient’s needs (Step 7). After a predefined period, for example a year, the patient’s health status is reassessed and the cyclic clinical process repeated.

Table 1

Longlist of suitable questionnaires; questionnaires written in italic typeface were chosen in a consensus meeting of the project team to be used in the feasibility study.

POPULATION HEALTH
OUTCOMEQUESTIONNAIREAUTHORS/SOURCEDUTCH VALIDATED VERSIONNUMBER OF QUESTIONSSCORING RANGE*
Quality of LifeSatisfaction with Life Scale (SWLS)Diener, 1985 [8].Yes55–35
Life Satisfaction Questionnaire (LSQ)Fugl-Meyer, 1991 [9].Yes91–6
Health stateEQ-5D-5LHerdman, 2011 [10].Yes6–0.446–1
SF12Ware, 1996 [11].Yes120–100
Functioning and participationICF Primary Care instrumentPostma, 2018 [12].Yes731–5#
Self-managementPatient Activation Measure (PAM)Hibbard, 2004 [13].Yes130–100
Health related quality of lifePROMIS global 10Hays, 2009 [14].Yes10T-score
Well-beingWell-being of Older People (WOOP)Hackert, 2021 [15].Yes99–45
Well-beingICE-CAP-OMakai, 2013 [16].Yes50–1.00
PATIENT EXPERIENCE
OUTCOMEQUESTIONNAIREAUTHORS/SOURCEDUTCH VERSIONNUMBER OF QUESTIONSSCORING RANGE*
Chronic carePatient Assessment of Care for Chronic Conditions (PACIC)Glasgow, 2005 [17].Yes201–5
Quality of primary careConsumer Quality Index (CQ-index) Daytime General Practice CareMeuwissen, 2009 [18].Yes530–10
Patient experience of chronic care in primary carePREM Chronic careHendriks, 2016 [19].Yes25Net promotor score
Person centred coordinated care experiencesPerson Centred Coordinated Care Experiences Questionnaire (P3CEQ)Lloyd, 2019 [20].Yes110–30
Person centred care experiencePerson Centred Primary Care Measure (PCPCM)Etz, 2019 [21].No118–44
Continuity of careNijmegen Continuity Questionnaire (NCQ)Uijen, 2011 [22].Yes301–5

[i] * Higher score is better. # Higher score is worse.

ijic-25-4-8998-g2.png
Figure 2

Flowchart of inclusion of patients and healthcare professionals.

Table 2

Characteristics of the patients and healthcare professionals participating in the feasibility study.

PATIENTSNUMBER (%) (n = 96)
Sex, male36 (38%)
Age, ≥65 years48 (50%)
Paid work, yes37 (39%)
Educational level1
Low36 (38%)
Middle28 (30%)
High30 (31%)
Limited literacy221 (22%)
Lifestyle
Alcohol consumption, average of ≥1 glass/day28 (29%)
Active smoking, yes21 (22%)
Exercise, ≥5 days per week347 (49%)
Polypharmacy, chronic use of ≥5 different medications447 (49%)
≥3 chronic diseases, yes50 (52%)
sDMP inclusion
COPD/asthma, yes32 (33%)
CVRM, yes87 (91%)
Diabetes, yes43 (45%)
Included in 2 sDMPs524 (25%)
HEALTHCARE PROFESSIONALSNUMBER (%) (n = 26)
Sex, male5 (19%)
Practice nurses13 (50%)
General practitioners13 (50%)
5 or more years relevant working experience18 (69%)
Healthcare professionalsNumber (%)(n = 26)
Type of practice
Solo practice8 (31%)
Group practice12 (46%)
Practice integrated in multidisciplinary healthcare center6 (23%)

[i] 1 Educational level was determined based on the highest completed education, creating 3 groups:

High: higher vocational or university education,

Middle: higher secondary general education or post-secondary vocational education,

Low: all other types of education.

2 Patients who reported to ever have experienced problems with reading medical flyers or information.

3 Based on the Dutch exercise guideline [29] that states to exercise at least 5 days a week for at least 30 minutes per session.

4 Polypharmacy is defined as the chronic use of 5 or more different medications [3031]. We excluded dermatological medications, ferrous fumarate, artificial tears, vitamins, and fibres. Other eye drops were included if they were chronically used. Medications were included in chronic use if they were prescribed for ≥90 days. Combination preparations were counted as 2 separate medications.

5 The combination Diabetes sDMP and CVD/CVRM sDMP was not included as patients with both DM2 and CVD or elevated cardiovascular risk are only treated in the sDMP for DM2.

Table 3

Scores on the selected questionnaires for the outcomes ‘patient experience’ and ‘population health’ in 96 patients with one or more chronic conditions. Questionnaires marked italic were selected for the forthcoming evaluation study.

QUESTIONNAIRECOMPLETED QUESTIONNAIRE AT BASELINE (n)COMPLETED QUESTIONNAIRE AT 6 MONTHS FOLLOW UP + (n)MEDIAN (IQR) SCORE AT BASELINEMEAN (SD) AT BASELINEMEAN CHANGEp-VALUEMCID†n (%) NEGATIVE MCIDn (%) NO CHANGEn (%) POSITIVE MCIDn (%) DIFFICULTY WITH QUESTIONS (n = 86)
EQ-5D-5L index96790.85 (0.1)0.83 (0.19)–0.010.470*0.1013 (16.5)58 (73.4)8 (10.1)8 (9.3)
EQ-5D-5L visual analogue scale (VAS)967980 (20)77.49 (16.02)1.870.09*8.0111 (13.9)49 (62.0)19 (24.1)8 (9.3)
Life Satisfaction Questionnaire (LSQ)91795 (0.7)4.97 (0.59)–0.020.567*0.3017 (22.7)43 (57.3)15 (20.0)10 (11.6)
Person-Centred Coordinated Care Experience Questionnaire (P3CEQ)967914.0 (9.8)12.65 (6.19)–0.230.924*3.1020 (25.3)40 (50.6)19 (24.1)18 (20.9)
Patient Activation Measure (PAM)887262.5 (19.8)64.63 (14.62)0.620.394*7.3111 (16.7)39 (59.1)16 (24.2)15 (17.4)
PROMIS–general physical health (GPH)967945.7 (11.3)45.82 (7.90)0.960.071#3.9510 (12.7)51 (64.6)18 (22.8)6 (7.0)
PROMIS–general mental health (GMH)967945.3 (8.3)46.74 (6.64)–0.500.843*3.3217 (21.5)49 (62.0)13 (16.5)6 (7.0)
Satisfaction with Life Scale (SWLS)967929 (9.8)26.80 (6.82)–0.090.997*3.4114 (17.7)51 (64.6)14 (17.7)17 (19.8)
Well-being of Older People (WOOP)967937.1 (5.1)37.07 (4.49)–0.270.290*2.2518 (22.8)50 (63.3)11 (13.9)5 (5.8)

[i] +Statistical tests were only performed on paired values of 79 participants who completed all questionnaires. Baseline characteristics were similar to the group of 96 patients. *Wilcoxon test; † MCID defined as 0.5 × SD of the baseline questionnaire score; # Paired t-test. MCID = minimal clinically important difference; PROMIS = patient reported outcomes measurement information system; SD = standard deviation.

Table 4

Different scenarios for the composite primary outcome for the evaluation study.

QUESTIONNAIRE:n (%)
PROMIS GPH; MCID improved18 (22.8)
PROMIS GMH; MCID improved13 (16.5)
P3CEQ; MCID improved19 (24.1)
Scenarios for combining the three questionnaires* to define the composite primary outcome:
MCID improved of at least one (decrease allowed)37 (46.8)
MCID improved of at least one (no decrease allowed)24 (30.4)
MCID improved of at least two (decrease allowed)9 (11.4)
MCID improved of at least two (no decrease allowed)8 (10.1)
MCID improved of all three questionnaires4 (5.1)

[i] * PROMIS GPH & GMH & P3CEQ; GPH = general physical health; GMH = mental health; MCID = minimal clinically important difference; P3CEQ = Person Centred Coordinated Care Experiences Questionnaire; PROMIS = patient reported outcomes measurement information system.

DOI: https://doi.org/10.5334/ijic.8998 | Journal eISSN: 1568-4156
Language: English
Submitted on: Oct 2, 2025
Accepted on: Oct 24, 2025
Published on: Nov 6, 2025
Published by: Ubiquity Press
In partnership with: Paradigm Publishing Services
Publication frequency: 4 issues per year

© 2025 Lena H. A. Raaijmakers, Tjard R. Schermer, Hester E. van Bommel, Jan H. Vercoulen, Tessa van Loenen, Erik W. M. A. Bischoff, published by Ubiquity Press
This work is licensed under the Creative Commons Attribution 4.0 License.