Postpartum haemorrhage and risk of long-term hypertension and cardiovascular disease : an English population-based longitudinal study using linked primary and secondary care databases

Objective To investigate the long-term risk of developing hypertension and cardiovascular disease (CVD) among those women who suffered a postpartum haemorrhage (PPH) compared with those women who did not. Design Population-based longitudinal open cohort study. Setting English primary care (The Health Improvement Network (THIN)) and secondary care (Hospital Episode Statistics (HES)) databases. Population Women exposed to PPH during the study period matched for age and date of delivery, and unexposed. Methods We conducted an open cohort study using linked primary care THIN and HES Databases, from 1 January 1997 to 31 January 2018. A total of 42 327 women were included: 14 109 of them exposed to PPH during the study period and 28 218 matched for age and date of delivery, and unexposed to PPH. HRs for cardiovascular outcomes among women who had and did not have PPH were estimated after controlling for covariates using multivariate Cox regression models. Outcome measures Risk of hypertensive disease, ischaemic heart disease, heart failure, stroke or transient ischaemic attack. Results During a median follow-up of over 4 years, there was no significant difference in the risk of hypertensive disease after adjustment for covariates (adjusted HR (aHR): 1.03 (95% CI: 0.87 to 1.22); p=0.71). We also did not observe a statistically significant difference in the risk of composite CVD (ischaemic heart disease, heart failure, stroke or transient ischaemic attack) between the exposed and the unexposed cohort (aHR: 0.86 (95% CI: 0.52 to 1.43; p=0.57). Conclusion Over a median follow-up of 4 years, we did not observe an association between PPH and hypertension or CVD