The role of socioeconomic factors on discontinuation of insulin during pregnancy—methodological challenges from a Swedish register-based study

Abstract

Aim: Continuous use of antidiabetic medication, especially insulin, is crucial for diabetes management. In pregnancy, adherence to medication is generally low and may also be associated with lower socioeconomic status. However, little is known about discontinuation of insulin in pregnant women and the potential role of socioeconomic factors. Therefore, this study aims to measure the associations between socioeconomic factors and insulin discontinuation during pregnancy in women using insulin prior to the start of pregnancy in Sweden. Subjects and methods: This cohort study identified pregnancies recorded in the Swedish Medical Birth Register from 2006 to 2016 in women receiving insulin prior to the start of pregnancy (N = 6029). Discontinuation of insulin was defined as not receiving a refill within 120 days from the previous refill. Associations between discontinuation and socioeconomic factors were investigated via logistic regression. Sensitivity analyses were performed using different definitions of discontinuation. Results: Women discontinued insulin use in 34.2% of pregnancies. The odds ratios (ORs) of discontinuation of insulin were 1.17 [95% confidence interval (CI): 1.01–1.37] for women with lower household disposable incomes and 1.14 (95% CI: 1.01–1.29) for women with lower educational levels. When testing a change in the maximum refill gap from 91 days to 180 days, women with lower educational levels and those born in non-Nordic countries showed greater associations with discontinuation. Conclusion: The definition of discontinuation affects the level of association of socioeconomic factors with discontinuation. Nevertheless, discontinuation of insulin is common in Sweden, especially in the lower socioeconomic groups. The socioeconomic inequality in insulin use behavior is worth noting.