Risk Score Development to Predict Postpartum Cardiovascular Disease Incorporating Pregnancy and Nonpregnancy Factors

BACKGROUND: Pregnancy events including severe maternal morbidity are associated with future cardiovascular disease (CVD), yet no models exist to identify at-risk individuals postpartum. OBJECTIVES: The purpose of this study was to develop a risk score with likelihood ratios (LRs) predicting postpartum CVD based on pregnancy and nonpregnancy CVD risk factors. METHODS: Using national administrative hospitalization data from Canada 2008-2021, the authors randomly selected 1 delivery per individual aged 18-55 years without pre-existing CVD. Cox proportional hazards models were used to predict CVD hospitalization, following individuals from 43 days after delivery discharge until CVD, censoring at in-hospital noncardiovascular death, subsequent pregnancy, or end of study. Risk scores and LRs for CVD hospitalization were generated using model coefficients. Model performance was characterized using C-statistics with 95% CIs. RESULTS: In this cohort of 1,992,972 individuals (median follow-up 3.7 years [Q1-Q3: 1.6-7.9 years]), the LRs for CVD within 1 year of delivery were 0.55 (95% CI: 0.49-0.61), 1.42 (95% CI: 1.28-1.57), and 7.81 (95% CI: 6.69-9.11) for standardized risk scores of