Assessing Validity of ICD‐9‐CM and ICD‐10 Administrative Data in Recording Clinical Conditions in a Unique Dually Coded Database

Abstract

Objective. The goal of this study was to assess the validity of the International Classification of Disease, 10th Version (ICD‐10) administrative hospital discharge data and to determine whether there were improvements in the validity of coding for clinical conditions compared with ICD‐9 Clinical Modification (ICD‐9‐CM) data. Methods. We reviewed 4,008 randomly selected charts for patients admitted from January 1 to June 30, 2003 at four teaching hospitals in Alberta, Canada to determine the presence or absence of 32 clinical conditions and to assess the agreement between ICD‐10 data and chart data. We then recoded the same charts using ICD‐9‐CM and determined the agreement between the ICD‐9‐CM data and chart data for recording those same conditions. The accuracy of ICD‐10 data relative to chart data was compared with the accuracy of ICD‐9‐CM data relative to chart data. Results. Sensitivity values ranged from 9.3 to 83.1 percent for ICD‐9‐CM and from 12.7 to 80.8 percent for ICD‐10 data. Positive predictive values ranged from 23.1 to 100 percent for ICD‐9‐CM and from 32.0 to 100 percent for ICD‐10 data. Specificity and negative predictive values were consistently high for both ICD‐9‐CM and ICD‐10 databases. Of the 32 conditions assessed, ICD‐10 data had significantly higher sensitivity for one condition and lower sensitivity for seven conditions relative to ICD‐9‐CM data. The two databases had similar sensitivity values for the remaining 24 conditions. Conclusions. The validity of ICD‐9‐CM and ICD‐10 administrative data in recording clinical conditions was generally similar though validity differed between coding versions for some conditions. The implementation of ICD‐10 coding has not significantly improved the quality of administrative data relative to ICD‐9‐CM. Future assessments like this one are needed because the validity of ICD‐10 data may get better as coders gain experience with the new coding system.