Diabetes not sole cause of depression in diabetic patients, study suggests

NEW YORK Increased risk of depression in diabetic patients could be the result of more frequent contacts with the medical system, rather than the disease itself, a new study suggested.

Previous research suggested that diabetic individuals faced a higher risk of depression, yet few studies accounted for the number of primary care visits that patients make, noted Patrick O'Connor of HealthPartners Research Foundation in Bloomington, Minn., and his colleagues.

To investigate, O'Connor and his colleagues analyzed records from a large medical group that treated about 225,000 patients between 1997 and 2003 and found that the likelihood of being newly diagnosed with depression fell as the number of times the patient visited the doctor increased.

Among the group of diabetic patients with few physician visits during the study period were 46% more likely to be newly diagnosed with depression during the course of the study. But for the diabetic patients who had more than 10 physician visits during the study period, the risk of a new depression diagnosis was similar to that of non-diabetic individuals who visited their physicians equally often.

The reason why people -- diabetic or not -- who visit the doctor less often are more likely to be depressed isn't clear, the researchers said. "These data might indicate that primary care clinicians are good at recognizing depression after only a few visits," they wrote. "Other explanations are possible, however; perhaps physician who do not recognize depression early are not likely to diagnose it later."

This study was published in Annals of Family Medicine, July/August 2009.