PDF herunterladen
Am J Perinatol 2021; 38(09): 889-996
DOI: 10.1055/s-0041-1729160
SMFM Fellowship Series Article

From Pruritus to Cholestasis: Building a Statistical Model and Online Application to Predict a Diagnosis Prior to Bile Acid Determination

Authors

  • Andres F. Ramirez Zamudio 

    1   Department of Obstetrics, Gynecology, and Reproductive Science, Icahn School of Medicine at Mount Sinai, New York, New York

  • Erica Monrose

    2   Icahn School of Medicine at Mount Sinai, New York, New York

  • Stephanie Pan

    3   Department of Population Health Science and Policy, The Blavatnik Family Women's Health Research Institute, Icahn School of Medicine at Mount Sinai, New York, New York

  • Lauren Ferrara

    4   Division of Maternal Fetal Medicine, Department of Obstetrics, Gynecology, and Reproductive Science, Icahn School of Medicine at Mount Sinai, New York, New York
Weitere Informationen
Auch verfügbar auf
   Lizenzen und Reprints
Preview

Abstract

Objective This study aimed to create a statistical model using clinical and laboratory parameters to predict which patients presenting with pruritus in pregnancy will have elevated total bile acids (TBA) and thus, have a high risk of intrahepatic cholestasis of pregnancy (ICP).

Study Design Retrospective cohort study of patients presenting with pruritus in pregnancy and had TBA sent from a single public hospital from January 1, 2017, to December 31, 2017. Primary outcome is TBA ≥ 10 µmol/L. Multivariate logistic regression with stepwise and backward variable selection were used to create predictive models. Four models were compared using Akaike information criterion (AIC), C-statistic, and the DeLong nonparametric approach to test for differences between area under the curve (AUC) of receiver operating characteristic (ROC) curves. Internal validation was performed via fivefold cross-validation technique on the best-fitting, most parsimonious model.

Results Of the 320 patients with pruritus, 153 (47.8%) had elevated bile acid levels ≥10 µmol/L. Sixty-nine variables were assessed for association with the primary outcome. Five variables were significantly associated with elevated TBA: pruritus of palms and soles (adjusted odds ratio [aOR]: 2.35 [95% confidence interval, CI: 1.22, 4.54]), gestational hypertension (aOR: 0.10 [95% CI: 0.02, 0.60]), log of total bilirubin (aOR: 4.71 [95% CI: 2.28, 9.75]), systolic blood pressure (aOR: 0.97 [95% CI: 0.94, 0.99]), and alanine aminotransferase (aOR: 1.05 [95% CI: 1.02, 1.07]). The final model was chosen for being parsimonious while having the lowest AIC with highest AUC (0.85; 95% CI: 0.81, 0.89). Internal validation using a probability threshold of 50% demonstrated a sensitivity of 65.5%, specificity of 83.5%, and accuracy of 75.1%.

Conclusion We provide a predictive model using five simple variables to determine the probability that a patient presenting with pruritus in pregnancy carries the diagnosis of ICP. This tool, available via a web app, is designed to aid providers and enhance clinical judgment in difficult triage situations.

Key Points

  • Currently, no standard method to triage pruritus in pregnancy exists.

  • We present a predictive statistical model using five readily available clinical variables.

  • Final calculator yields probability of having intrahepatic cholestasis of pregnancy.

Keywords

calculator - cholestasis - pruritus - pregnancy - transaminitis


Publikationsverlauf

Eingereicht: 06. Juli 2020

Angenommen: 02. März 2021

Artikel online veröffentlicht:
02. Mai 2021

© 2021. Thieme. All rights reserved.

Thieme Medical Publishers, Inc.
333 Seventh Avenue, 18th Floor, New York, NY 10001, USA