Association of Traditional Chinese Medicine Therapy with Risk of Total Hip Replacement in Patients with Nontraumatic Osteonecrosis of the Femoral Head: A Population-Based Cohort Study

Background. Osteonecrosis of the femoral head (ONFH) contributes to 45% of total hip replacements (THRs) annually in Taiwan. Nontraumatic ONFH (NONFH) is multifactorial; no effective Western medicine is available to delay the disease process. This population-based cohort study investigated the association of traditional Chinese medicine (TCM) therapy with risk of THR in patients with NONFH. Methods. This retrospective study was conducted using claims data from all insured residents covered by the National Health Insurance from 2000 to 2010. We enrolled 1,680 newly diagnosed ONFH patients who had not undergone THR, before or within 6 months after diagnosis of ONFH; these patients did not exhibit hip fracture or dislocation before the endpoint. In total, 595 propensity score-matched pairs were selected from among 1,028 TCM users and 652 non-TCM users. The association between TCM use and risk of THR was analyzed using a Cox proportional hazard model. Kaplan-Meier and log rank tests were performed to plot the cumulative incidence of THR. Results. The mean follow-up periods were 5.00 years and 3.57 years for TCM and non-TCM cohorts, respectively. Compared to the non-TCM cohort, the TCM cohort had fewer patients undergoing THR surgery (25.4% vs. 18.2%, adjusted hazard ratio: 0.60, p<0.0001). The risk of reduction was noted in the group aged 30-59 years (adjusted hazard ratio: 0.56, p<0.0001), but there was no association with gender nor socioeconomic status. There was a significantly lower cumulative incidence of THR in TCM users (p<0.0001). Shu-Jing-Huo-Xue-Tang and Yan Hu Suo were the most frequently prescribed formula and single herb, respectively. Conclusions. NONFH patients using TCM had a lower risk of THR; the risk of reduction was noted in the group aged 30-59 years but was not associated with gender nor socioeconomic status. TCM might be useful in conservative treatment for NONFH.