Validating exacerbations of asthma in electronic health records: a systematic review
File(s)
Published version
Author(s)
Moore, Elizabeth
Gassasse, Zakariah
Sinha, Ian
Hawcutt, Daniel B
Quint, Jennifer K
Type
Journal Article
Abstract
Background
Previous studies have shown that the algorithms and code lists used to define asthma exacerbations vary across different sources of data, if reported at all. Defining and validating asthma exacerbations in electronic health records (EHR) would help to improve future research on asthma using EHR by leading to more consistent and comparable evidence.
Methods
We systematically reviewed the literature to evaluate studies that define exacerbations of asthma in EHR and report which algorithms have the highest validity. An adapted version of the QUADAS-2 designed for this review was used to assess risk of bias.
Results
Of the studies yielded by the search, only five met the inclusion criteria. Eligible studies used algorithms that contained codes from versions or modifications of either the 9th or 10th revisions of the International Statistical Classification of Diseases and Related Health (ICD-9 or ICD-10), and validity scores varied. Using the ICD-9 code 493 within algorithms to detect asthma exacerbations, sensitivity scores varied from 44.8% to 91.28% and specificity was >85%. Using the ICD-9 code 493.xx as the principal and secondary diagnosis in claims data, validity measures were all >85%. Using the ICD-10 code J45, scores for sensitivity, specificity and negative predictive value were also all >85%.
Conclusions
Algorithms have been used to identify asthma exacerbations in EHR with varying degrees of validity. Algorithms including the ICD-9 code 493.xx or the ICD-10 code J45 to detect asthma exacerbations had high validity scores. However, there was a risk of bias in these studies and urgent work is needed using robust methods to validate definitions for future research using EHR.
Previous studies have shown that the algorithms and code lists used to define asthma exacerbations vary across different sources of data, if reported at all. Defining and validating asthma exacerbations in electronic health records (EHR) would help to improve future research on asthma using EHR by leading to more consistent and comparable evidence.
Methods
We systematically reviewed the literature to evaluate studies that define exacerbations of asthma in EHR and report which algorithms have the highest validity. An adapted version of the QUADAS-2 designed for this review was used to assess risk of bias.
Results
Of the studies yielded by the search, only five met the inclusion criteria. Eligible studies used algorithms that contained codes from versions or modifications of either the 9th or 10th revisions of the International Statistical Classification of Diseases and Related Health (ICD-9 or ICD-10), and validity scores varied. Using the ICD-9 code 493 within algorithms to detect asthma exacerbations, sensitivity scores varied from 44.8% to 91.28% and specificity was >85%. Using the ICD-9 code 493.xx as the principal and secondary diagnosis in claims data, validity measures were all >85%. Using the ICD-10 code J45, scores for sensitivity, specificity and negative predictive value were also all >85%.
Conclusions
Algorithms have been used to identify asthma exacerbations in EHR with varying degrees of validity. Algorithms including the ICD-9 code 493.xx or the ICD-10 code J45 to detect asthma exacerbations had high validity scores. However, there was a risk of bias in these studies and urgent work is needed using robust methods to validate definitions for future research using EHR.
Date Issued
2026-04-01
Date Acceptance
2026-03-20
Citation
European Respiratory Review, 2026, 35 (180)
ISSN
0905-9180
Publisher
European Respiratory Society (ERS)
Journal / Book Title
European Respiratory Review
Volume
35
Issue
180
Copyright Statement
© The authors 2026 This version is distributed under the terms of the Creative Commons Attribution Licence 4.0.
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/42203235
PII: 35/180/260004
Subjects
Humans
Electronic Health Records
Asthma
Reproducibility of Results
Predictive Value of Tests
International Classification of Diseases
Algorithms
Disease Progression
Publication Status
Published
Coverage Spatial
England
Article Number
260004
Date Publish Online
2026-05-27