# Reason for hospitalization contrasting adjudication versus ICD-10-CM coding among persons with HIV, 2016–2019

## TL;DR

This study compares ICD-10-CM coding with expert review to determine hospitalization reasons in people with HIV, finding that coding is mostly accurate but needs improvement in certain cases.

## Contribution

The study evaluates the accuracy of ICD-10-CM coding versus adjudication for hospitalization reasons in HIV-positive individuals.

## Key findings

- ICD-10-CM coding agreed with adjudication in 73% of hospitalizations.
- Adjudication was needed for patients with complex hospitalization courses or poorly controlled HIV.
- Inadequate ICD coding occurred in 6% of cases.

## Abstract

People with HIV (PWH) have disproportionately high hospitalization rates, the reasons for which are incompletely understood. Hospitalization reasons based on International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) discharge codes may lead to misclassification. We evaluated the performance of ICD-based reason for hospitalization with adjudication in PWH.

We randomly sampled 302 of 1428 hospitalizations (21%) between 2016 and 2019 among PWH in the UNC CFAR Clinical Cohort Study (UCHCC). ICD-based reason was defined as first-listed ICD discharge diagnosis, or second if the principal diagnosis was HIV. We contrasted ICD-based reason and adjudication with four outcomes: complete agreement (same category and diagnosis), partial agreement (same category, different diagnosis), disagreement (different category and diagnosis), and inadequate ICD coding (no single ICD-10-CM code was appropriate).

Overall the 302 hospitalizations occurred among 204 PWH, 69% of whom were male, with median age 51 years (interquartile range [IQR], 40–58), and CD4 count 539 (IQR, 242–789), at time of hospitalization. Adjudication completely agreed with ICD-based reason in 73% hospitalizations, partially agreed in 14%, disagreed in 8%, and ICD codes were inadequate in 6%. Patient characteristics associated with lower proportion of complete or partial agreement were recent CD4 count < 200, nadir CD4 < 50, ≥ 15 discharge diagnoses, length of stay ≥ 4 days, and HIV as a principal diagnosis.

Overall ICD codes performed well in capturing reason for hospitalization in most cases. However, adjudications are needed among certain groups of patients, including those with poorly controlled HIV and complex hospitalization course.

The online version contains supplementary material available at 10.1186/s12981-026-00855-8.