Are elevated outpatient natriuretic peptide levels associated with severe maternal morbidity in pregnant patients?
Outpatient natriuretic peptide testing is rarely performed during pregnancy, and while elevated levels are associated with severe maternal morbidity, their independent predictive value appears limited after adjusting for comorbidities.
Objective: To describe patterns of outpatient natriuretic peptide (NP) testing and levels, including brain NP (BNP) and N-terminal pro-BNP (NT-proBNP), among pregnant patients with and without heart disease (HD) and the association between NP and severe maternal morbidity (SMM). Methods: A nationwide sample of pregnant patients delivering at ≥20 weeks in the Epic Cosmos dataset from 2017-2023 was extracted. Outpatient NP levels drawn between 24-34 weeks’ gestation were identified, categorized as normal or elevated (BNP ≥ 100 or NT-proBNP ≥ 300 pg/mL), and described according to the presence or absence of congenital or acquired HD based on ICD-10 codes. The primary outcomes were CDC-defined SMM and non-transfusion SMM. Among those with NP testing, the association between elevated levels and SMM was assessed using logistic regression after applying stabilized inverse probability treatment weights (SIPTW) that included demographic characteristics, HD, obesity, and other medical comorbidities. Results: Of 3,935,745 unique pregnancies, 3,920,088 (99.6%) had no NP testing, 14,180 (0.4%) had normal NP, and 1,477 (0.04%) had elevated NP. Of those with any HD, 1.6% underwent NP testing. A greater proportion of those with normal NP (N=1,287 9.1%) and elevated NP (N=406 27.5%) experienced SMM compared to those without NP testing (N=99,176 2.5%; p<0.001), with similar results for non-transfusion SMM. The odds of SMM and non-transfusion SMM were higher in patients with elevated NP levels; this association persisted, but was attenuated, in SIPTW-adjusted models (SMM crude OR 14.6, 95% CI 13.0, 16.4 and aOR 1.2, 95% CI 1.1, 1.2; non-transfusion SMM crude OR 25.4, 95% CI 22.6, 28.6 and aOR 1.2, 95% CI 1.2, 1.2). Conclusion: NP testing remains underutilized during pregnancy, even among patients with heart disease. Elevated levels are associated with higher SMM risk, although the attenuation in association after covariate adjustment suggests its additive value in predicting SMM may be limited.
Denoble et al. (Thu,) reported a other.