Table 7 Findings of included studies

Diabetes and depression

Risk of all-cause mortality

6 months: RD 0.00, 95%CI -0.02 to 0.02, 2/7 studies of relevance (Watson 2013)

12 months: RD 0.00, 95%CI -0.02 to 0.01, 2/7 studies of relevance (Watson 2013)

Depression

Depression scores

SMD −0.32, 95%CI -0.53 to −0.11, 7 studies (Atlantis 2014)

SMD − 0.41 95%CI -0.63 to − 0.20, 6 studies; 4 of relevance (Smith 2016)

Response rate

6 months: RR 1.64, 95%CI 1.28 to 2.10, 4 studies (Huang 2013)

12 months: RR 1.42, 95%CI 1.14 to 1.76, 4 studies (Huang 2013)

End of follow-up: RR 1.33, 95%CI 1.05 to 1.68, 4 studies (Huang 2013)

Remission

6 months: RR 1.33, 95%CI 1.01 to 1.75, 2 studies (Huang 2013)

RD 0.123, 95%CI 0.064 to 0.183, 3 studies (Watson 2013)

12 months: RR 1.20, 95%CI 0.93 to 1.55, 2 studies (Huang 2013)

RD 0.077, 95%CI 0.016 to 0.137, 3 studies (Watson 2013)

18 months: RD 0.075, 95%CI 0.013 to 0.136, 3 studies (Watson 2013)

24 months: RD 0.045, 95%CI -0.023 to 0.113, 3 studies (Watson 2013)

End of follow-up: RR 1.15, 95%CI 0.87 to 1.52, 2 studies (Huang 2013)

Reduction (of at least 50%) in Mental Health score

6 months: RD 0.20, 95%CI 0.14 to 0.26, 4/9 studies of relevance (Watson 2013)

12 months: RD 0.17, 95%CI 0.12 to 0.23, 3/7 studies of relevance (Watson 2013)

18 months: RD 0.12, 95%CI 0.02 to 0.22, 1/3 studies of relevance (Watson 2013)

Diabetes clinical outcome (HbA1c level)

6 months: MD − 0.06, 95%CI -0.24 to 0.12, 4 studies (Huang 2013)

MD 0.13, 95%CI -0.22 to 0.48, 3 studies (Watson 2013)

12 months: MD − 0.07, 95%CI -0.28 to 0.13, 4 studies (Huang 2013)

MD 0.24, 95%CI -0.14 to 0.62, 3 studies (Watson 2013)

End of follow-up:

WMD − 0.33, 95%CI -0.66 to 0.00%, 7 studies (Atlantis 2014)

MD − 0.13, 95%CI -0.46 to 0.19, 7 studies (Huang 2013)

WMD − 0.33, 95%CI -0.66 to 0.00%, 7 studies (Smith 2016)

Effect of depression remission on HbA1c

SMD for depression scores were unable to predict the WMD in HbA1c values; p − 0.828, coefficient 0.19, 95%CI -1.93 to 2.31, 7 studies (Atlantis 2014)

Symptom improvement

Watson et al. reported greater depression symptom improvement scores in intervention groups at

6 months: MD 0.38, 95%CI 0.24 to 0.51, 3/5 studies of relevance (Watson 2013)

12 months: MD 0.38, 95%CI 0.30 to 0.46, 3/5 studies of relevance (Watson 2013)

24 months: MD 0.18, 95%CI 0.10 to 0.26, 2/3 studies of relevance (Watson 2013)

Systolic blood pressure

MD −3.10, 95%CI -7.26 to 1.06, 5 studies (Smith 2016)

Access and utilisation of healthcare services

12 months: range: 42 to 84%; usual care range: 16 to 33%, 3/4 studies of relevance (Watson 2013)

Quality of care in terms of mental health treatment satisfaction

12 months: RD 0.205, 95%CI 0.112 to 0.299, 3/4 studies of relevance (Watson 2013)

24 months: RD 0.14, 95%CI 0.06 to 0.21, 1/3 studies of relevance (Watson 2013)