Measuring depressive symptoms using the Patient Health Questionnaire-9 in Hong Kong Chinese subjects with type 2 diabetes.

BACKGROUND

Depression is common in type 2 diabetes although the prevalence in Chinese patients remains unclear. We validated the Patient Health Questionnaire(PHQ-9), a popular depression screening tool, in Chinese with type 2 diabetes, and documented the prevalence, demographic,and clinical characteristics associated with depression.

METHODS

A consecutive cohort of 586 Hong Kong Chinese outpatients completed the PHQ-9 during comprehensive diabetes complication assessment. Within 2-4 weeks, 40 patients were retested via telephone survey. Ninety-nine randomly selected patients were interviewed by psychiatrists using the Mini International Neuropsychiatric Interview as a golden standard. Receiver operating characteristic curve was used to assess performance of the PHQ-9.

RESULTS

The internal consistency of the PHQ-9 was 0.86 and test-retest reliability was 0.70. The 3 somatic items explained 53.6% of the PHQ-9 score. The optimal cutoff value was 7 with 82.6% sensitivity and 73.7% specificity, giving a depression prevalence of 18.3% (n=107). Of these, 18.7% had been previously diagnosed with depression. Depression was more prevalent in women than men. After controlling for confounders, patients with depression had higher HbA1c (7.80 ± 1.86% versus 7.43 ± 1.29%, [61.7 ± 20.4 versus 57.8 ± 14.1 mmol/mol], P<0.05), reduced likelihood of achieving HbA1c target of <7.0% (33.6% versus 41.8%, P<0.05), and were more likely to have self-reported hypoglycemia in the previous 3 months (18.7% versus 6.7%, P<0.01).

LIMITATION

A small sample was used in the criterion validation and the cross-sectional design precludes causal inference.

CONCLUSIONS

PHQ-9 is a validated tool for screening for depression, which is common and frequently undiagnosed in Chinese type 2 diabetic patients and is associated with suboptimal glycemic control, hypoglycemia, and somatization.