Purpose: To assess sex differences in treatment patterns after metformin initiation among type 2 diabetes mellitus (T2D) patients.
Methods: A cohort study was conducted using the Groningen Initiative to ANalyze Type 2 diabetes Treatment (GIANTT) primary care database. Patients aged ≥18 years initiating metformin were followed 2-5 years. Markov modeling was conducted to estimate treatment transition rates and calculate adjusted hazard ratios (aHR) with 95% confidence intervals (CI) comparing men with women adjusted for age, HbA1c level at initiation, and cardiovascular disease history. Kaplan-Meier analyses and Cox proportional-hazards models were used to determine the time to and likelihood of getting treatment intensification. HbA1c levels at initiation and intensification were compared using Mann-Whitney U tests.
Results: In total, 11 508 metformin initiators were included (50.1% women). The most common transition after initiation was a dose increase (probability women 0.52, men 0.59, no significant difference). Women were more likely than men to switch to any other non-insulin hypoglycemic agent after initiation (aHR 1.66; 95% CI 1.31-2.12), after dose increase (aHR 1.48; 95% CI 1.10-1.98) and after dose decrease (aHR 2.64; 95% CI 1.28-5.46). Time to intensification was longer, time to switching was shorter, and HbA1c levels at initiation and intensification were lower for women than men.
Conclusions: Sex disparities were observed in treatment transitions after metformin initiation. Women more often switched treatment than men, which suggest that prescribers acknowledge more tolerance or other problems for metformin in women. Men intensified treatment earlier and at higher HbA1c levels, indicative of a higher need for treatment intensification.
Keywords: longitudinal cohort study; sex disparities; treatment pattern; treatment prescribing; type 2 diabetes mellitus.
© 2023 The Authors. Pharmacoepidemiology and Drug Safety published by John Wiley & Sons Ltd.