Quality and Predictors of Diabetes Care Among Patients With Schizophrenia: A Danish Nationwide Study

OBJECTIVE: Patients with schizophrenia have a high prevalence of diabetes, but data on diabetes care quality for these patients are limited. This nationwide study compared the quality of diabetes care among individuals with and without schizophrenia and identified predictors of care quality.

METHODS: In a population-based cohort study, 83,813 individuals with diabetes seen at hospital outpatient clinics between 2005 and 2013, including 669 with comorbid schizophrenia, were identified from Danish registries. High-quality diabetes care was defined as having received ≥80% of guideline-recommended process performance measures. Variables assessed as predictors of diabetes care included patient-specific (sex, age, smoking, substance abuse, Global Assessment of Functioning score, and duration of schizophrenia), provider-specific (quality of schizophrenia care), and system-specific (annual patient contact volume of the diabetes clinic) factors.

RESULTS: Compared with individuals with diabetes only, those with diabetes and schizophrenia were less likely to receive high-quality diabetes care (relative risk [RR]=.91, 95% confidence interval [CI]=.88-.95) and less likely to receive several individual process performance measures of diabetes care, including blood pressure monitoring (RR=.98, CI=.96-.99), treatment with antihypertensive drugs (RR=.83, CI=.70-.97) and angiotensin-converting enzyme/angiotensin II receptor inhibitors (RR=.72, CI=.55-.93), screening for albuminuria (RR=.96, CI=.93-.99), eye examination at least once every second year (RR=.97, CI=.94-.99), and foot examination (RR=.96, CI=.93-.99). Predictors of poor diabetes care among individuals with schizophrenia included documented drug abuse and low contact volume of the diabetes clinic.

CONCLUSIONS: Individuals with schizophrenia received lower-quality diabetes care compared with those without schizophrenia. However, absolute differences in care were modest.