Health impacts of new‐onset diabetes in women post‐gestational diabetes mellitus: Insights from Hong Kong's territory‐wide data

ABSTRACT Aims/Introduction To determine the population health burden attributable to the development of diabetes among women with a history of gestational diabetes mellitus (GDM). Materials and Methods We conducted a retrospective analysis of women with a history of GDM attending the Hong Kong Hospital Authority between 2000 and 2019. The time‐varying population attributable fraction was calculated. Results A total of 76,181 women with a history of gestational diabetes mellitus were included, 6,606 of them developed diabetes during a median follow‐up of 8.6 years. The respective hazard ratios (95% confidence interval) among women with GDM who developed diabetes vs those with GDM only were 2.8 (2.2, 3.7) for cardiovascular disease (CVD), 4.8 (3.0, 7.7) for end‐stage kidney disease (ESKD), 2.2 (1.9, 2.6) for infection‐related hospitalization, and 1.8 (1.3, 2.4) for all‐cause mortality. The development of diabetes was associated with 1.3 (0.8, 1.7), 0.6 (0.3, 0.8), 3.2 (2.4, 4.0), and 0.5 (0.2, 0.9) additional incident cases per 1,000 person‐years, accounting for 24.0% (13.2%, 35.9%), 42.0% (22.5%, 58.8%), 10.8% (7.1%, 14.9%), and 6.0% (−3.1%, 16.1%) of absolute number of CVD, ESKD, infection‐related hospitalization, and all‐cause mortality over 20 years after GDM, respectively. Conclusions Diabetes is a significant contributor to the population health burden of some clinical outcomes in women with a history of gestational diabetes mellitus, but other risk factors need to be considered. In this population‐based cohort of Chinese women with a history of gestational diabetes mellitus, we found that the subsequent development of diabetes in women with GDM increased the hazards of cardiovascular and kidney diseases by 3‐ to 5‐fold, infection‐related hospitalization and all‐cause mortality by 2‐fold, and cancer by 20%. By 20 years post‐GDM, diabetes accounted for close to one half of the new cases of end‐stage kidney disease and one quarter of cardiovascular disease. Our results indicate that diabetes is an important contributor to selected clinical events in women with a history of gestational diabetes mellitus although other risk factors need to be considered.