(1013) The association between first trimester serum creatinine and pregnancy outcomes in patients with chronic hypertension

Pre-existing hypertension (HTN) and renal disease are known risk factors for adverse pregnancy outcomes, including pre-eclampsia (PreE). This study aimed to assess whether an elevated first trimester serum creatinine (sCr) in patients with chronic HTN, in the absence of pre-existing kidney disease, is associated with an increased risk of PreE.

Study Design:

This was a retrospective cohort study at a single tertiary center from 1/2018 to 12/2022. Inclusion criteria were patients with HTN with a first trimester sCr result. Exclusion criteria were pre-existing kidney disease, significant proteinuria in the first trimester, acute illness during sCr evaluation, and conditions known to increase the risk for adverse pregnancy outcomes including pregestational diabetes, autoimmune disease, multiple gestation, history of renal surgery, transplantation, donation, and isolated renal agenesis. An elevated sCr was defined as >0.7 mg/dL. The primary outcome was the diagnosis of PreE. Secondary outcomes included assessment of first trimester sCr in patients diagnosed with PreE, gestational age at PreE diagnosis and at delivery, small for gestational age (SGA), and gestational diabetes (GDM). Wilcoxon rank sum tests and Chi-squared tests were used.

Results:

226 patients with normal sCr and 76 with elevated sCr were identified. 82/226 (36%) in the normal sCr group developed PreE, compared to 36/76 (47%) in the elevated sCr group (p=0.11). First trimester sCr as a continuous variable was associated with an increased incidence of PreE diagnosis (p=0.03). Gestational age at PreE diagnosis (35.2±3.4 v 35.1±3.6w, p=0.845), gestational age at delivery (37.3±2.7 v 36.7±3.1w p=0.045), SGA (27 v 32% p=0.534), and GDM (15 v 20% p=0.494) were not different between groups.

Conclusion:

In the population studied, a first trimester sCr >0.7 mg/dL was not associated with an increased incidence of PreE, though this was associated with earlier gestational age at delivery. Patients who developed PreE had higher sCr in the first trimester on average than those who did not develop PreE.