BackgroundWe hypothesize that depression in type 2 diabetes might be associated with poor glycemic control, in part due to suboptimal self-care. We tested this hypothesis by examining the associations of depression with clinical and laboratory findings in a multicenter survey of Chinese type 2 diabetic patients. Method2538 patients aged 18-75 years attending hospital-based clinics in four cities in China underwent detailed clinical-psychological-behavioral assessment during a 12-month period between 2011 and 2012. Depression was diagnosed if Patient Health Questionnaire-9 (PHQ-9) score 10. Diabetes self-care and medication adherence were assessed using the Summary of Diabetes Self-care Activities and the 4-item Morisky medication adherence scale respectively. ResultsIn this cross-sectional study (mean age: 56.410.5[SD] years, 53% men), 6.1% (n=155) had depression. After controlling for study sites, patients with depression had higher HbA(1c) (7.92.0 vs. 7.72.0%, P=0.008) and were less likely to achieve HbA(1c) goal of <7.0% (36.2% vs 45.6%, P=0.004) than those without depression. They were more likely to report hypoglycemia and to have fewer days of being adherent to their recommended diet, exercise, foot care and medication. In logistic regression, apart from young age, poor education, long disease duration, tobacco use, high body mass index, use of insulin, depression was independently associated with failure to attain HbA(1c) target (Odds Ratio [OR]=1.56, 95%CI:1.05-2.32, P=0.028). The association between depression and glycemic control became non-significant after inclusion of adherence to diet, exercise and medication (OR=1.48, 95% CI 0.99-2.21, P=0.058). ConclusionDepression in type 2 diabetes was closely associated with hyperglycemia and hypoglycemia, which might be partly mediated through poor treatment adherence.