Table 1.

Characteristics of the selected articles.

	Author, year, country	Population	Study design; sampling strategies	Data source: data collection	Definition of multimorbidity	Number of chronic diseases	List of chronic diseases
1	Garin et al., 2015, China and India [17]	General population; 14794 individuals ≥ 18 years old	Cross-sectional; multistage clustered sampling	Study on Global AGEing and Adult Health (SAGE); structured interviews and physician's assessment	≥2 chronic diseases	12	Angina, arthritis, asthma, cataract, chronic obstructive pulmonary disease (COPD), depression, diabetes, edentulism, hypertension, cognitive impairment, obesity, and stroke
		General population; 11230 individuals ≥ 18 years old	Cross-sectional; multistage clustered sampling	Study on Global AGEing and Adult Health (SAGE); structured interviews and physician's assessment	≥2 chronic diseases	12	Angina, arthritis, asthma, cataract, chronic obstructive pulmonary disease (COPD), depression, diabetes, edentulism, hypertension, cognitive impairment, obesity, and stroke
2	Hussain et al., 2015, Indonesia [18]	General population; 9438 individuals ≥ 40 years old	Cross-sectional; multistage clustered sampling	Indonesian Family Life Survey (IFLS-4); self-reported questionnaire and trained nurse's assessment	≥2 chronic diseases	15	Hypertension, hypercholesterolaemia, cardiac diseases, obesity (body mass index ≥ 30), arthritis, vision abnormality, uric acid/gout, depression, chronic respiratory diseases, diabetes mellitus, hearing problem, stroke, liver disease, tuberculosis, and cancer
3	Wang et al., 2015, China [19]	General population; 1480 individuals ≥ 60 years old	Cross-sectional; cluster sampling	Confucius Hometown Aging Project (CHAP); structured interviews, clinical examinations, and laboratory tests	≥2 chronic diseases	16	Hypertension, diabetes, obesity, dyslipidemia, thyroid dysfunction, coronary heart disease, arrhythmia, eye problems, chronic obstructive pulmonary disease or asthma, depression, cognitive impairment, heart failure, stroke, hearing disorders, tumor, and arthritis
4	Wang et al., 2015, China [20]	General population; 21435 individuals 18–79 years old	Cross-sectional; multistage stratified cluster sampling	Jilin Provincial Chronic Disease Survey; structured interviews and clinical examination on BMI	≥2 chronic diseases in the past 12 months	18	Anemia, diabetes mellitus, severe vision reduction, hypertension, ischemic heart disease, cerebrovascular disease, chronic nasopharyngitis, chronic lower respiratory disease, chronic gastroenteritis/peptic ulcer, liver disease, cholecystitis/gallstones, arthritis, chronic low back pain, chronic nephritis, urolithiasis, prostatic hyperplasia (male), disorders of breast (female), and pelvic inflammatory disease (female)
5	Gu et al., 2017, China [21]	Primary care; 2452 individuals ≥ 60 years old	Cross-sectional; stratified cluster sampling	Community Health Service, Nanjing, Jiangsu province; structured interviews, self-reported questionnaire, and physician's assessment	≥2 chronic diseases	13	Hypertension, diabetes, joint disease, cataract, hearing disorder, dyslipidemia, coronary heart disease, stroke, kidney disease, gastrointestinal disease, lung disease, liver disease, and cancer
6	Gu et al., 2018, China [22]	Primary care; 411 individuals ≥ 60 years old	Cross-sectional; simple random sampling from Gu et al., 2016	Community Health Service, Nanjing, Jiangsu province; structured interviews, self-reported questionnaire, and physician's assessment	≥2 chronic diseases	13	Hypertension, diabetes, joint disease, cataract, hearing disorder, dyslipidemia, coronary heart disease, stroke, kidney disease, gastrointestinal disease, lung disease, liver disease, and cancer
7	Aoki et al., 2018, Japan [23]	General population; 3256 individuals 18-84 years old	Cross-sectional; quota sampling from residents' panel	Norm study; self-reported questionnaire	≥2 chronic diseases	17	Hypertension, diabetes, dyslipidemia, stroke, cardiac diseases, chronic respiratory diseases, digestive diseases, kidney diseases, urologic diseases, arthritis or rheumatism, lumbar diseases, neurologic diseases, mental disorders, endocrine diseases, malignancy, vision abnormalities, and skin diseases
8	Yao et al., 2019, China [24]	General population; 19841 individuals ≥ 50 years old	Cross-sectional; multistage sampling	China Health and Retirement Longitudinal Study (CHARLS); structured interviews and self-reported questionnaire	≥2 chronic diseases	15	Hypertension, dyslipidemia, diabetes or high blood sugar, cancer or malignant tumor, chronic lung disease, liver disease, heart problems, stroke, kidney disease, stomach or other digestive disease, emotional, nervous or psychiatric problems, memory-related disease, arthritis or rheumatism, hip fracture, and vision impairment