Evidence Hub

Targeted use of large language models for EHR-based computable phenotyping

Owens D, Cao J, Gupta M, Nguyen D, Peterson E, Navar AM

Journal of the American Medical Informatics Association : JAMIA, 2026

Abstract

OBJECTIVE: Computable phenotypes derived from electronic health records (EHRs) are central to clinical research and quality reporting. Although large language models (LLMs) can extract clinically rich information from unstructured notes, routine application to all patients is computationally expensive. We evaluated whether uncertainty-guided selective use of LLMs can improve phenotyping accuracy while preserving scalability.

MATERIALS AND METHODS: We developed a selective augmentation framework integrating structured and unstructured EHR data using uncertainty-guided triage. An ensemble of heterogeneous classifiers trained on structured data generated probabilistic phenotype predictions and uncertainty measures to identify patients at elevated risk of misclassification. Only flagged patients underwent LLM-based analysis of unstructured clinical notes using retrieval-augmented generation. LLM-derived outputs were incorporated as additional predictors in a final probabilistic model. Performance was evaluated for two registry-based phenotypes: diabetes mellitus and peripheral arterial disease (PAD), using internal cross-registry and external validation cohorts.

RESULTS: For diabetes mellitus, selective augmentation improved sensitivity in the internal validation cohort from 0.81 to 0.90 without loss of specificity (0.92). More than 70% of triage-flagged patients represented misclassifications by structured data alone. For PAD, selective augmentation markedly increased…

How strong is the evidence?

Evidence Hub reads this as a cohort study, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

Read the paper

Related studies

Go deeper in Evidence Hub

Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.

Open this study Sign up free