Incidence, risk factors, and outcomes of neonatal renal vein thrombosis in Ontario: population-based cohort study

Background — There is limited data at a population level on the burden, risk factors, and long-term outcomes of neonatal renal vein thrombosis (nRVT).

Objectives — We conducted a population-based cohort study to understand the epidemiology and outcomes of nRVT over a 25-year period in Ontario.

Methods — Using linked administrative health databases, all hospitalized neonates ≤28 days born in Ontario between 1992 and 2016 with nRVT were identified. The primary outcome was to calculate the incidence of nRVT and trend over time in Ontario. We also determined the risk factors associated with nRVT as well as the risk of long-term outcomes following nRVT, including chronic kidney disease (CKD), end-stage kidney disease (ESKD), all-cause mortality, and hypertension (HTN) compared to the healthy neonatal population without nRVT.

Results — The annual incidence rate (IR) of nRVT was 2.6 per 100,000 live births (n=85). Presence of respiratory distress syndrome (OR 8.01, 95% CI 4.90-13.1), congenital heart disease (OR 9.1, 95% CI 5.05-16.4), central venous catheterization (OR 3.9, 95% CI 1.89-7.93), maternal preeclampsia (OR 2.8, 95% CI 1.6-4.79), and maternal diabetes (2.36, 95% 1.36-4.07) conferred the highest risk for nRVT. Over a median follow-up of 15 years and after adjusting for confounders, neonates with nRVT vs. the comparator cohort had a 15.5-fold risk of CKD, HTN or death [n=49 (57.6%) vs n=90,050 (3%), 95% CI: 11.7-20.6], 12.3-fold increased risk of CKD or death [n=39 (46%) vs. n=32,016 (1%), 95% CI: 8.9-16.8] and a 15.7-fold increased risk of HTN [n=33 (39%) vs. n=64,458 (2%), 95% CI: 11.1-21.1]. None of the nRVT cohort developed ESKD. The median time to composite outcome of CKD, HTN or death was 11.1 years.

Conclusions — Patients with a history of nRVT remain at higher risk than the general population for long-term morbidity or mortality, indicating the need for long-term follow-up.