Table 1.

Characteristics of included studies

Author (year)	Design	Study setting	No. of patients	Mean age, years	Country	Male, %	Depression prevalence, %	Depression assessment	Compared groups	Source of estimates	Adjusted factors
Katon et al 21	Cross-sectional	Community	4193	65	USA	51	20.5	PHQ-9	Insulin versus non-drug	Adjusted	Age, sex, education, marital status, employment, race, BMI and smoking, Rx Risk Score, HbA1c, duration of diabetes, treatment intensity, number of complications
Bell et al 20	Cross-sectional	Community	696	74	USA	50.7	15.8	CES-D	Insulin versus oral medication; insulin versus non-drug	Adjusted	Age, sex, ethnicity, education, marital status, income, diabetes duration, number of medications, BMI, HbA1c, chronic conditions, PCS Score
Noh et al 17	Hospital-based	Hospital	204	53	Korean	53	32.4	BDI	Insulin versus oral medication	Adjusted	Age, sex, BMI, duration of diabetes, HbA1c, occupation, education, marital status, family history of diabetes, hypertension, diabetic complications, cerebrovascular disease, IHD
Hermanns et al 40	Cross-sectional	Hospital	236	52.2	Germany	60.6	33	BDI; CES-D	Insulin versus non-insulin	Unadjusted	NA
Pawaskar et al 31	Prospective cohort	Medicare Health Maintenance Organisation	792	72	USA	44	17.3	CES	Insulin versus sulfonylurea	Adjusted	Age, sex, number of prescriptions, antidiabetic medication, perceived health status, health-related quality of life, number of hospitalisations, ER visits
Li et al 18	Cross-sectional	Surveillance Programme	16 651	≥18	USA	42	14.4	PHQ	Insulin versus non-insulin	Unadjusted	NA
Ali et al 33	Cross-sectional	Hospital	3845	NA	Mixed (South Asia and UK)	52.8	9.3	Medical records	Insulin versus non-insulin	Adjusted	Age, gender, comorbidities, complications, insulin and oral anti-diabetic medication use, BMI, HbA1c, duration of diabetes and deprivation
Raval et al 36	Cross-sectional	Hospital	300	54	India	49	41	PHQ-9	Insulin versus non-insulin	Adjusted	Age, gender, obesity, diabetic complications, blood pressure, duration of disease, income, education, BMI, HbA1c, diabetic complications, dyslipidaemia, number of medicines
Zuberi et al 42	Cross-sectional	Hospital	286	52	Pakistan	39.2	50	HADS	Insulin versus oral medication	Unadjusted	NA
Stanković et al 41	Cross-sectional	Hospital	90	55.5	Serbia	34.4	51.1	PHQ, BDI or interview	Insulin versus oral medication	Unadjusted	NA
Lynch et al 43	Cross-sectional	Hospital	201	NA	USA	27.4	19.9	CES-D	Insulin versus non-insulin	Unadjusted	NA
Osme et al 44	Cross-sectional	Outpatient clinic	138	≥30	Brazil	27.5	44.6	HAD	Insulin versus non-insulin	Unadjusted	NA
Trento et al 45	Cross-sectional	Outpatient clinic	498	67.6	Italy	52.6	14.2	ZSDS	Insulin versus non-insulin	Unadjusted	NA
Roy et al 37	Cross-sectional	Outpatient clinic	417	53.2	Bangladesh	50.6	34	PHQ-9	Insulin versus oral medication+diet; insulin+oral medication versus oral medication+diet	Adjusted	Age, gender, education, income, region, CVD, hypertension, diabetic complications, BMI, HbA1c
Joseph et al 46	Cross-sectional	Hospital	230	53.6	India	51.7	45.2	PHQ-9	Insulin versus oral medication	Unadjusted	NA
Hayashino et al 47	Cross-sectional	Hospital	3573	66	Japan	61.1	3.4	PHQ-9	Insulin versus oral medication or diet	Unadjusted	NA
Gorska-Ciebiada et al 34	Cross-sectional	Outpatient clinic	276	74	Poland	46	29.7	GDS	Insulin versus oral medication	Adjusted	Age, sex, education, marital status, smoking, physical activity, duration of diabetes, BMI, HbA1c, lipid levels, diabetic complications, previous HA or use of HA drugs, hyperlipidaemia, number of comorbid conditions, hypoglycaemia
Sweileh et al 48	Cross-sectional	Hospital	294	60	Palestine	44.2	40.2	BDI	Insulin versus non-insulin	Unadjusted	NA
YY Zhang et al 52	Cross-sectional	Hospital	2538	56.4	China	53	6.1	PHQ-9	Insulin versus oral drugs	Unadjusted	NA
Rodriguez Calvin et al 51	Cross-sectional	Hospital	275	64.5	Spain	56.4	32.7	BDI	Insulin versus oral medication	Unadjusted	NA
Camara et al 35	Cross-sectional	Outpatient clinic	491	58	Guinea	37	34.4	HADS	Insulin versus oral medication	Adjusted	Age, HbA1c, hypertension, BMI, residence zone, socioeconomic status
Sun et al 39	Cross-sectional	Community	229 047	57.4	China	34.4	5.9	PHQ-9	Insulin versus oral medication or diet	Adjusted	Age, sex, BMI, HbA1c, smoking, alcohol, physical activity, education, occupation, marital status, self-report cardiometabolic disorders, diabetes treatment, diabetes duration
WJ Zhang et al 32	Cross-sectional	Hospital	412	59.8	China	50.2	5.7	BDI	Insulin versus oral medication	Adjusted	Age, gender, education, marital status, occupation, insurance, HbA1c, BMI, DM history, diabetic complications, duration of DM, smoking, alcohol, exercise, sleeping hours
Luca et al 50	Cross-sectional	Hospital	128	64.7	Italy	58.6	50.8	HAM-D	Insulin versus oral medication or diet	Unadjusted	NA
Kikuchi et al 49	Cross-sectional	Community	4218	65.5	Japan	57.1	10.6	CES-D	Insulin versus non-insulin	Unadjusted	NA
Jacob et al 38	Cross-sectional	Community	90 412	65.5	Germany	50.2	30.3	Medical records	Insulin versus non-insulin	Adjusted	Age, gender, insurance, diabetic complications, CVD, HbA1c
Cols-Sagarra et al 53	Cross-sectional	Community	411	70.8	Spain	46.2	29.2	PHQ-9	Insulin versus oral medications or diet	Unadjusted	NA
Habtewold et al 54	Cross-sectional	Hospital	276	44	Ethiopia	47	44.7	PHQ-9	Insulin versus oral medication	Unadjusted	NA

BDI, Beck Depression Inventory; BMI, body mass index; CES-D, Centre for Epidemiologic Studies-Depression; CVD, cardiovascular disease; DM, diabetes mellitus; ER, emergency room; GDS, Geriatric Depression Scale; HADS, Hospital Anxiety and Depression Scale; HAM-D, Hamilton Rating Scale for Depression; IHD, ischaemic heart disease; PCS, Physical Component Summary Score; PHQ, Patient Health Questionnaire; ZSDS, Zung Self-Rating Depression Scale.