# Promoting algorithmic equity in in-hospital mortality prediction

> **NIH NIH R01** · UNIVERSITY OF PENNSYLVANIA · 2024 · $763,883

## Abstract

Project Summary/Abstract
In-hospital mortality prediction models (MPMs) are widely used in clinical research and practice; but existing
MPMs suffer from algorithmic bias, or systematic differences in performance by group. We and others showed
that MPMs for hospitalized patients – the Sequential Organ Failure Assessment score (SOFA) and Laboratory-
based Acute Physiology Score, version 2 (LAPS2) – overestimate mortality for Black patients with acute
respiratory failure (ARF) or sepsis, and underestimate mortality for white patients. Biased MPMs may thus
produce healthcare inequities and flawed inferences about contributions of sociodemographics to clinical
outcomes. Therefore, we seek to develop, validate, and demonstrate the impact of a novel MPM that optimizes
fairness (i.e., defined by ‘groupwise optimality,’ optimizing subgroup performance without sacrificing predictive
accuracy) across key subgroups defined by race, ethnicity, sex, age, primary language, insurance status, and
social vulnerability without sacrificing accuracy. We will address key causes of bias in model development:
differential missing data and calibration biases. We will study hospitalized ARF and sepsis patients because
they face high risks of biased predictions due to diagnostic uncertainty and high mortality risk, and these
syndromes pose increased mortality risks for racial and ethnic minorities. In Aim 1, we will develop a fairness-
informed, in-hospital MPM. We will identify predictive features using those in common MPMs and structured
data within 24 hours of presentation. We will assess missing data bias by comparing feature proportions by
subgroup, excluding biased features, using a 2018-2023 cohort of ~220,000 encounters across 28 hospitals in
the University of Pennsylvania and Kaiser Permanente Northern California health systems. We will select
features using elastic net regression, and develop and internally validate a set of novel MPMs for use at
admission, building logistic and elastic net regression, and machine learning models. We will implement model
bias audits and mitigation strategies (i.e., multicalibration, optimizing calibration across subgroups without
sacrificing predictive accuracy) to develop a set of optimized MPMs. We will evaluate performance overall and
by subgroup, and compare performance to SOFA, LAPS2, and the Epic Deterioration Index. In Aim 2, we will
conduct focus groups among key stakeholders to present blinded results of the novel MPMs, varying subgroup
performance tradeoffs and decision thresholds, to select the model and thresholds that best promote equity
and accuracy. In Aim 3, we will test the external validity of this MPM among patients admitted to MedStar
Health, a health system serving primarily racial and ethnic minority patients, using a different electronic health
record. In Aim 4, we will quantify the impact of the novel MPM on key use cases, by (1) re-analyzing our team’s
pragmatic trials to assess the impact of risk adjustm...

## Key facts

- **NIH application ID:** 10978755
- **Project number:** 1R01HL171311-01A1
- **Recipient organization:** UNIVERSITY OF PENNSYLVANIA
- **Principal Investigator:** Rachel Kohn
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $763,883
- **Award type:** 1
- **Project period:** 2024-09-09 → 2029-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10978755

## Citation

> US National Institutes of Health, RePORTER application 10978755, Promoting algorithmic equity in in-hospital mortality prediction (1R01HL171311-01A1). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10978755. Licensed CC0.

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