SAT-200 INCREASED RISK OF LONG-TERM RENAL DISEASE IN WOMEN WHO DELIVER PRETERM INFANTS: A POPULATION-BASED COHORT STUDY

Abstract

Chronic kidney disease (CKD) is a major cause of global morbidity, with estimated prevalence of 7-12% among women. Preterm delivery is a common adverse pregnancy outcome, and an independent risk factor for maternal cardiovascular disease. Little is known about the association between preterm delivery and subsequent maternal renal function, and whether any association is independent of preeclampsia or intra-uterine growth restriction. We aimed to determine whether women who deliver preterm infants are at increased risk of CKD and end-stage renal disease (ESRD). Using data from the Swedish Medical Birth Register, singleton live births from 1973-2012 were identified and linked to data from the Swedish Renal Register and National Patient Register (up to 2013). Women with pre-pregnancy renal disease, cardiovascular disease, diabetes, hypertension, systemic lupus erythematosus were excluded. Preterm delivery was the main exposure, and treated as a time-dependent variable. Primary outcomes were maternal CKD or ESRD. Cox regression was used for analysis, adjusting for maternal age, year of delivery, country of origin, parity, inter-pregnancy interval, smoking, BMI, gestational diabetes. Adjusted hazard ratios (aHR) and 95% confidence intervals (CI) were estimated. Models were stratified by history of preeclampsia or small for gestational age (SGA) delivery. The sample comprised 1,943,716 women with 3,760,429 live-births. Overall, 162,918 women (8.4%) delivered preterm. The mean (±SD) follow-up was 20.3 (±11.6) years. 18,001 women (0.9%) developed CKD, and 1,268 (0.07%) developed ESRD. Women with history of preterm delivery were at increased risk of CKD (aHR 1.46, 95% CI 1.39-1.53) and ESRD (aHR 2.52, 95% CI 2.17-2.93) compared with women who delivered at term (≥37 weeks). Women with history of extremely preterm delivery (<28 weeks) were at particularly high risk of CKD (aHR 1.94, 95% CI 1.60-2.34) and ESRD (aHR 3.99, 95 %CI 2.25-7.06). The risk of renal disease was greatest in women who experienced preterm delivery complicated by preeclampsia (vs. normal term deliveries, for CKD, aHR 2.81, 95% CI 2.46-3.20; for ESRD, aHR 6.70, 95% CI 4.70-9.76). However, spontaneous preterm delivery was also associated with significantly increased risk of CKD and ESRD independent of all other factors. Women who deliver preterm infants are at higher risk of CKD and ESRD, particularly those with very/extremely preterm deliveries. This association persists independently of preeclampsia or SGA. Preterm delivery warrants consideration as part of overall CKD risk prediction models. Women and clinicians should be informed of this heightened risk to plan for appropriate preventive interventions.