Aims/hypothesis: The association between a history of hypertensive disorders of pregnancy (HDP) and subsequent type 2 diabetes (referred to throughout as diabetes) remains inconclusive. We reviewed the most recent evidence to quantify the association of previous HDP with incident diabetes.
Methods: A systematic search of MEDLINE, Embase and CINAHL was performed up to 17 February 2020 to identify observational studies of the association between HDP (pre-eclampsia or gestational hypertension) and incident diabetes. Studies of women with pre-pregnancy diabetes were excluded. Two independent reviewers screened citations and abstracted results. Study quality was assessed in duplicate using the Newcastle-Ottawa Scale. Random-effects models were used to pool effect estimates. Heterogeneity was assessed using the I2 statistic.
Results: After screening 4617 citations, 16 cohort studies with a total of 3,095,457 participants were included (unspecified HDP n = 5, pre-eclampsia only n = 4, gestational hypertension and pre-eclampsia n = 7). Risks of subsequent diabetes were significantly higher in women with a history of any HDP (HDP: adjusted hazard ratio [aHR] 2.24, 95% CI 1.95, 2.58; gestational hypertension: aHR 2.19 [95% CI 1.69, 2.84]; pre-eclampsia: aHR 2.56 [95% CI 2.02, 3.24]; preterm pre-eclampsia: aHR 3.05 [95% CI 2.05, 4.56]). The association between HDP and diabetes persisted in studies that adjusted for gestational diabetes mellitus (aHR 2.01 [95% CI 1.77, 2.28]).
Conclusions/interpretation: HDP are independently associated with a higher risk of diabetes. Further study is needed to determine how HDP contribute to diabetes risk prediction to develop evidence-based screening and prevention strategies. Graphical abstract.
Keywords: Diabetes; Gestational hypertension; Hypertensive disorders of pregnancy; Meta-analysis; Pre-eclampsia; Systematic review.