Factors Affecting the Accuracy of Clinical Coding in the Casemix System in a Teaching Hospital: Cross-Sectional Study

Abstract Background Accurate clinical coding is critical in the casemix system to ensure proper resource allocation, health care policy planning, and data reliability. Inaccurate coding can result in significant financial losses to the hospital. To date, the implications of inaccurate coding in casemix implementations in Malaysia have rarely been explored. Objective This study aimed to evaluate the accuracy of clinical coding and identify factors associated with accurate coding practices in a major teaching hospital in Malaysia. Methods A cross-sectional study was conducted using 445 inpatient discharge records from Hospital Canselor Tuanku Muhriz from January 2023 to December 2023. Stratified random sampling was applied across 4 departments. Coding accuracy was determined by comparing electronic medical record entries to a gold-standard set by trained coders and specialists. Descriptive and bivariate analyses were performed accordingly. Results This study found that the overall clinical coding accuracy was 76.4% (340/445). Documentation completeness ( P <.001) and coding turnaround time ( P =.02) were significantly associated with coding accuracy. Other variables such as patients’ sex, patient age, department, and coder experience were not significantly associated. Clinical coding accuracy in this setting was suboptimal. Conclusions Continuous training and regular audits are recommended to improve coding quality and ensure reliable casemix data for policy and funding decisions.