Using the comorbidity index to evaluate the medical utilization and outcomes of total hip replacement through analyzing National Insurance claimed data

Objective: To evaluate the correlation between the pre-operative Charlson comorbidity index (CCI) and post-operative medical utilization and quality for patients who underwent a total hip replacement (THR). Methods: The claimed data from the National Health Insurance for patients who underwent elective primary THR in 2000 was used in this study. The correlation between CCI and the parameters including length of stay, medical fee, rate of mortality, and readmission within thirty days and one year were analyzed after adjustment of patients' characters (age, gender, major diagnosis), characters of hospitals (area, owner and size), times of in-hospital rehabilitations and complications. Result: The THR patients with a present pre-operative CCI score of more than 2 had a higher medical fee (NT $14,900 versus NT $12,500), thirty-day mortality (2.8% versus 0.4%), thirty-day readmission rate (31.4% versus 7.2%), one-year mortality (15.3% versus 1.8%), one-year readmission rate (147.5% versus 40.0%) and longer length of stay (11.9 days versus 9.4days) than those with a zero score. After adjustment of the confounding factors, the preoperative CCI score was still significantly positively related to the above parameters. Even the CCI score within one year was also positively related to the above parameters. The present score CCI was more efficient than the CCI score within one year for the response to the medical utilization and quality. Conclusion: The CCI score was highly correlated with the utilization of medical care during hospitalization and medical quality after discharge. The present CCI was more efficient than the CCI within one year, except for in respect to the one-year readmission rate. The CCI score could be used for the correction of severity of THR patients. NHI could use CCI to evaluate the rationality of reimbursements. The CCI score could also be applied to the hospital for prediction of the prognosis of THR.