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Abstract
Purpose
Claim data from Taiwan’s National Health Insurance (NHI) database have previously been utilized in the study of COPD. However, there are limited data on the positive predictive value of claim data for COPD diagnosis. Therefore, this study aimed to characterize and validate the COPD cohort identified from the NHI research database.
Methods
This cross-sectional study compared records from claim data with those from a medical center. From 2007 to 2014, a COPD cohort was constructed from claim data using ICD9-CM codes for COPD. The diagnostic positive predictive value of these data was assessed with reference to physician-verified COPD. In addition, a multivariate logistic regression model was built to identify independent factors associated with the positive predictive value of COPD diagnosis by claim data.
Results
During the 8-year study period, a total of 12,127 subjects met the criterion of having two or more outpatient codes in 1 year or one or more inpatient COPD codes in their claim data. Of this total, the diagnosis of COPD was verified by physicians in 7,701 (63.5%) subjects. Applying a more stringent criterion – three or more outpatient codes or two or more inpatient codes – improved the diagnostic positive predictive value to 72.2%. Age ≥65 years and a claim for spirometry were the two most important factors associated with the positive predictive value of claim-data-defined COPD. Adding spirometry testing to diagnostic ICD9-CM codes for COPD increased the positive predictive value to 84.6%.
Conclusion
This study emphasizes the importance of validation of disease-specific diagnosis prior to applying an administrative database in clinical studies. It also indicates the limitation of ICD9-CM codes alone in recognizing COPD patients within the NHI research database.
Supplementary materials
Table S1 Proportions of physician-verified COPD patients stratified by age, sex, and smoking status in the study cohort (n=12,127)
Table S2 Comparisons of clinical characteristics of spirometry-confirmed COPD and other patient cohorts (n=12,127)
Acknowledgments
We thank the staff of the Eighth Core Lab, Department of Medical Research, National Taiwan University Hospital for technical support during the study, and we also thank the staff of the Department of Medical Research, National Taiwan University Hospital for the Integrated Medical Database (NTUH-IMD). This study was supported in part by grants from the Ministry of Science and Technology, Taiwan (MOST 107-2634 F-002-015 and 106-2627-M-002-022). The funder had no role in study design, data collection/analysis, decision to publish, or preparation of the manuscript.
Disclosure
The authors report no conflicts of interest in this work.