Comparison of total hip and knee joint replacement in patients with rheumatoid arthritis and osteoarthritis: a nationwide, population-based study.

INTRODUCTION: Patients with rheumatoid arthritis (RA) and osteoarthritis (OA) may require total hip replacement (THR) or total knee replacement (TKR). The present study aimed to compare the demographic characteristics and medical costs of RA and OA patients from Taiwan who underwent either THR or TKR.
METHODS: The medical records of patients who had undergone THR or TKR from 1 January 1996 to 31 December 2010 were obtained from the Taiwan National Health Insurance Research Database (NHIRD). In all, we found 49 and 146 RA patients who received THR and TKR, respectively, and 1,191 and 6,574 OA patients who received THR and TKR, respectively. The gender, age, Charlson comorbidity index (CCI), hospital grade, age at registration in the catastrophic illness dataset, and medical utilisation costs of the different groups were compared.
RESULTS: There were statistically significant differences in age, CCI score, drug costs and surgery costs between RA and OA patients. Joint replacement incidence was lower in RA patients than in OA patients, and among patients who underwent THR, total medical costs incurred were higher for RA patients than OA patients. RA patients who underwent THR incurred a significantly greater total medical utilisation cost in the outpatient department (3 months before surgery and 12 months after surgery) than OA patients who underwent THR.
CONCLUSION: Analysis of Taiwan NHIRD with regard to patients who had undergone either THR or TKR indicated that RA patients were younger than OA patients, and that significantly more medical resources were used for RA patients before, during and after hospitalisation for these procedures.