Serious mental illness and diabetes care among California adults

Background. Studies of medical care among diabetics with serious mental illness (SMI) have produced equivocal results, some show adequate and others show suboptimal treatment. This study examines the relationship of SMI to diabetes care among adults using a large survey, adjusting for sociodemographics, insurance, income, and physical health status.

Methods. The California Health Interview Survey, conducted biannually by UCLA since 2001, is a population-based, random digit dial telephone household survey. The 43,020 completed surveys obtained in 2005 are representative of 26.4 million adults. SMI was defined by a Kessler 6 scale score greater than or equal to 13. Stata S/E 9.2 was used for survey-adjusted multi-variable logistic regression analyses.

Results. Physicians had told 3,348 survey respondents (representing 1.8 million California adults) that they had diabetes. A total of 7.3% of diabetes patients had Kessler 6 scores above the SMI criterion. SMI predicted diabetes control medication nonadherence (OR = 0.57, 95% CI= 0.38 - 0.85); moreover SMI predicted lower likelihood of physicians checking their patients' feet for sores within the last year (OR = 0.50, 95% CI = 0.30 – 0.83). On the other hand, SMI was not significantly associated with physicians dilating patients' eyes for exams in the last 2 years or checking hemoglobin A or C levels in the last year.

Conclusions. SMI is associated with medication nonadherence and one aspect of suboptimal care. Those clinically responsible for the care of diabetic patients with SMI must understand patients' limits as well as other factors that may underlie less comprehensive care.