Indicators of quality of diabetes care in persons with type 2 diabetes with and without severe mental illness: a Danish nationwide register-based cohort study

BACKGROUND: This study aims to examine quality of diabetes care in persons with type 2 diabetes with and without severe mental illness (SMI). METHODS: In a nationwide prospective register-based study, we followed persons with type 2 diabetes in Denmark with and without SMI including schizophrenia, bipolar disorder, or major depression. Quality of care was measured as receipt of care (hemoglobin A1c, low-density lipoprotein-cholesterol and urine albumin creatinine ratio assessment and eye and foot screening) and achievement of treatment targets between 2015 and 2019. Quality of care was compared in persons with and without SMI using generalized linear mixed models adjusted for key confounders. FINDINGS: We included 216,537 persons with type 2 diabetes. At entry 16,874 (8%) had SMI. SMI was associated with lower odds of receiving care, with the most pronounced difference in urine albumin creatinine ratio assessment and eye screening (OR: 0.55, 95% CI: 0.53–0.58 and OR: 0.37 95% CI: 0.32–0.42, respectively). Among those with an assessment, we found that SMI was associated with higher achievement of recommended hemoglobin A1c levels and lower achievement of recommended low-density lipoprotein-cholesterol levels. Achievement of recommended low-density lipoprotein-cholesterol levels was similar in persons with versus without schizophrenia. INTERPRETATION: Compared to persons without SMI, persons with SMI were less likely to receive process of care, with the most pronounced differences in urine albumin creatinine ratio assessment and eye screening. FUNDING: This study was funded by 10.13039/100018562Steno Diabetes Center Copenhagen through an unrestricted grant from 10.13039/501100009708Novo Nordisk Foundation.