Socioeconomic disparities in glycaemic control in people living with type 2 diabetes in Finland

Abstract Background The aim was to assess the socioeconomic disparities in glycaemic control in before diagnosis and early stage of the disease in adult people living with type 2 diabetes (PwT2D) in Finland. Methods PwT2D were identified from several national healthcare registries using ICD-9, ICD-10 and ICPC-2 codes, reimbursement rights and medicine purchases. Indicators of socioeconomic status (SES) were obtained from Statistics Finland and laboratory measurements from National Patient Data Repository. SES was measured in highest education level (4 levels) and annual income quintiles. Ordinary least-squares regression was used to analyse SES differences HbA1c levels before and 2 years after diagnosis, separately for men and women, adjusted for age and year of diagnosis. The study period was from 2014 to 2021. Results Lowest income quintile had highest HbA1c at diagnosis; up to 2.2 mmol/mol (95% CI 1.5-2.9) higher than other income quintiles in men, and up to 1.6 mmol/mol higher (95% CI 0.97-2.1) in women. Two years after diagnosis, the lowest income quintile still had significantly higher HbA1c, but the level had slightly decreased; up to 1.3 mmol/mol (95% CI 0.92-1.7) in men and up to 0.77 mmol/mol (95% CI 0.44-1.1) in women. Before T2D diagnosis, primary level education was associated to higher HbA1c only in women, up to 1.9 mmol/mol (95% CI 0.92-2.8), while in men there were no significant differences between different education groups. After 2 years, primary level education group had higher HbA1c in both sexes, up to 1.7 mmol/mol (95% CI 1.2-2.3) higher in men and up to 1.3 mmol/mol (95% CI 0.72-1.8) higher in women. Conclusions Lower SES was associated with higher HbA1c before and 2 years after T2D diagnosis. The association of income and HbA1c level was slightly reduced within the first 2 years after diagnosis, but educational differences increased in men, while trending towards slight reduction in women. Key messages • There are significant socioeconomic differences in glycaemic control both before diagnosis and after 2 years of treatment of type 2 diabetes. • Early management of T2D in Finland may slightly reduce socioeconomic differences in glycemic control, but the differences remain significant.