Table 1.

Study characteristics of included studies

Study	Location	Design	Participants	Multimorbidity	Intervention	Setting	Endpoint
Hochhalter et al, 201023	USA	Randomised controlled trial	26 patients in appointment group, 27 in safety group, and 26 in usual group. Mean age 76 in appointment group, 73 in safety group and 73 in usual group	At least two of the following chronic illnesses: arthritis, lung disease, heart disease, diabetes, hypertension, depression or osteoporosis	Patient engagement, patient group workshop and individual coaching intervention	Primary care clinics, Scott & White Centre for Diagnostic Medicine	PAM-13, Communication with physician’s scale, HRQOL-14
Mateo-Abad et al, 202027	Spain	Quasi-experimental study	101 patients in the intervention group and 99 patients in the usual care group. Mean age 79	A minimum of two chronic diseases, with at least one of them being chronic obstructive pulmonary disease, diabetes mellitus, or chronic heart failure (CHF)	Care coordination and communication between health providers and patient empowerment and home-based care; all supported by ICT-based platforms	Integrated care organisations	Use of services, clinical variables (such as BMI, blood pressure, heart rate, blood glucose), Geriatric Depression Scale, Functional status (Barthel Index)
Naik et al, 201928	USA	Randomised controlled trial	136 in the intervention group, and 89 in control group. Mean age 61	Uncontrolled diabetes and depression	Proactive population screening and telephone delivery of a collaborative goal-setting intervention	Veterans Affairs Medical Centre	Change in depression symptoms using PHQ-9 and HbA1c
Reed et al, 201829	Australia	Randomised controlled trial	114 in the intervention group, and117 in the control group. Age range: 60+	At least two chronic diseases	Self-management support programme for older with multiple chronic conditions	General practices	Self-rated health
Salisbury et al, 201822	England and Scotland	Cluster-randomised trial	797 patients in the intervention group, and 759 in the usual care group. Mean age 71 in intervention group and 70,7 in the usual care group	At least three types of chronic conditions	Patient-centred strategies for management of multi-morbidity, 3D intervention	General practices	EQ-5D-5L
Schwarze et al, 202031	USA	Randomised controlled trial	223 patients in the intervention group, and 223 patients in the usual care group. Mean age 71 in intervention group and 72.6 in usual care group	At least one comorbidity and an oncologic or vascular problem	Question prompt list brochure targeting informational needs of patients considering major surgery	Surgeons’ clinics	No of questions asked by patients and family during the recorded visit, Perceived Efficacy in Patient-Physician Interactions-5, Measure Yourself Concerns and Well-being
Shively et al, 201321	USA	Randomised, 2-group, repeated-measures design	43 patients in the Intervention group, and 41 I the group with usually care. Mean age 66,1 years	Heart failure and comorbidities	Patient activation intervention compared with usual care in patients with Heart failure	Veterans Affairs San Diego Healthcare System	PAM, Self-Care of Hearth Failure Index, Medical Outcomes Study
Tay et al, 201824	Singapore	Prospective cohort study	170 in the intervention group and 60 in the control group. Mean age in the intervention group is 82 years and 84 years in control group	Dementia and comorbidities	Person-centred care in Care for Acute Mentally Infirm Elders	Hospital	Well-being Ill-being Pittsburg Agitation Scale Modified Barthel Index EQ-5D Index Score
Tinsel et al, 201320	Germany	Cluster randomised controlled trial	552 patients in the intervention group, and 568 in the control group. Mean age 63,8 in intervention group and 65 in control group	Hypertension and at least one relevant comorbid disorder (diabetes mellitus, coronary heart disease, heart attack, stroke, or peripheral arterial occlusive disease)	Shared decision-making (SDM) in General practice with patients with uncontrolled hypertension	General practice	SDM-Q-9, SBP
Ulin et al, 201626	Sweden	Controlled before-and-after design	125 patients in the intervention group, and 123 in control group. Mean age range: 77–80	CHF and comorbidities	Gothenburg Person-centred care in patients hospitalised	Department of Medicine at Sahlgrenska University Hospital/stra in Gothenburg	No of days from admission to First notice to the municipality Second notice to the municipality Notice to the municipality that the patient was ready for discharge from hospital
Wong et al, 201425	Hong Kong	Observational matched cohort study	1.141 in the intervention group and 1.141 in the control group. Mean age 64	Type 2 diabetes mellitus and hypertension	Patient Empowerment Programme in General Outpatient Clinics (GOPC)	GOPC	HbA1c, SBP, diastolic blood pressure, LDL-cholesterol
Willadsen et al, 201830	Denmark	Randomised controlled trial	970 patients in the intervention group and 539 in the group with usual care. Mean age 64,7 in intervention group and 64,5 I usual care group	Diabetes and multimorbidity	Structured personnel care in patients with diabetes	General practice	Self-rated health, diabetes symptoms

BMI, body mass index; 3D, Based on dimensions of health, depression, and drugs; EQ-5D-5L, Survey instrument produced by the EuroQol Group; HbA1c, haemoglobin A1c; HRQOL, health-related quality of life; LDL, low-density lipoprotein; PAM, Patient Activations Measurements; PHQ-9, Patient Health Questionnaire 9; SBP, systolic blood pressure.