Impact of different hypertensive disorders of pregnancy on cardiovascular disease risk and all-cause mortality in women with type 1 diabetes

Objectives Our aim was to assess how pre-eclampsia, gestational hypertension, and chronic (pre-pregnancy) hypertension, compared to no hypertensive disorders during pregnancy, impact development of cardiovascular disease and all-cause mortality in type 1 diabetes (T1D). Methods We included 190 T1D women with median age of 29.4 (interquartile range 26.0–33.3) years at delivery between 1988 and 1994 at the Helsinki University Hospital, and who were later re-examined within the Finnish Diabetic Nephropathy Study. Of these, 43 (22.6%) had had pre-eclampsia, 32 (16.8%) gestational hypertension, 20 (10.5%) chronic hypertension, and 95 (50.0%) had remained normotensive during the index pregnancy. We retrieved follow-up data on cardiovascular events and mortality from national registries until the end of 2020. Results During a median 27.9 (25.4–30.7) years of follow-up, 46 (24.2%) experienced a composite cardiovascular event and 25 (13.2%) died from any cause. In Cox regression analysis, the risk of a cardiovascular event was increased for chronic hypertension [hazard ratio, HR 3.45 (95% CI 1.25–9.54)], gestational hypertension [HR 3.63 (1.55–8.51)], and pre-eclampsia [HR 5.07 (2.31–11.11)] compared with the non-hypertension group, after adjustment for delivery age and age at T1D onset. The corresponding risk of all-cause mortality was increased for chronic hypertension [HR 3.31 (1.06–10.35)] and pre-eclampsia [HR 2.92 (1.07–7.98)], but not for gestational hypertension [HR 1.26 (0.33–4.85)]. After further adjustment for diabetic kidney disease or diabetic retinopathy as a time-dependent covariate, the association with cardiovascular disease remained for pre-eclampsia and gestational hypertension, while for mortality, none of the associations were significant. Conclusion Hypertension during pregnancy is associated with increased risk of cardiovascular events during long-term follow-up in women with T1D, with pre-eclampsia conferring the highest risk. For all-cause mortality, chronic hypertension and pre-eclampsia, but not gestational hypertension, increases the risk of death, yet not independently of diabetic kidney disease. Graphical abstract Supplementary Information The online version contains supplementary material available at 10.1186/s12933-025-02804-7.