Diabetes care among individuals with and without schizophrenia in three Canadian provinces: A retrospective cohort study.

Objective: Diabetes is present in approximately 10% of people living with schizophrenia and substantially contributes to early mortality, but some aspects of diabetes care among those with schizophrenia have been inadequately investigated to date. We assessed diabetes care and comorbidity management among people with and without schizophrenia.

Methods: We conducted a cohort study with data obtained from primary care electronic medical records stored in the Diabetes Action Canada (DAC) National Repository from Alberta, Ontario, and Quebec, Canada. The population studied included patients with diabetes, with and without schizophrenia, who had at least 3 primary care visits in a 2 year period between July 2017 and June 2019. Outcomes included glycemia; diabetes complication screening and monitoring; antihyperglycemic and cardioprotective medication prescription; health service use.

Results: We identified 69,512 patients with diabetes; 911 (1.3%) of whom also had schizophrenia. Prevalence of high HbA1C (>8.5%) (9083/68601; 13.2% vs. 137/911; 15.0%) and high blood pressure (>130/80 mmHg) (4248/68601; 6.2% vs. 73/911; 8.0%) was similar between the two groups. Half (50.0%) of patients with schizophrenia (n = 455) had 11 or more primary care visits in the past year, compared with 27.8% of people without schizophrenia. (p < 0.0001). Patients with schizophrenia had lower odds of ever having blood pressure recorded (OR = 0.81, 95% CI 0.71-0.94) and fewer of those with chronic kidney disease (CKD) were prescribed renin-angiotensin aldosterone system inhibitors, compared to patients without schizophrenia (10.3% vs 15.8%, p = 0.0005).

Conclusions: Patients with diabetes and schizophrenia achieved similar blood glucose and blood pressure levels to those without schizophrenia, and had more primary care visits. However, they had fewer blood pressure readings and lower prescription of recommended medications among those who also had CKD. These results are both encouraging and represent opportunities for improvement in care.