Integration of Chinese Herbal Medicine into Routine Care Was Related to Lower Risk of Chronic Kidney Disease in Patients with Rheumatoid Arthritis: A Population-Based Nested Case–Control Study in Taiwan

OBJECTIVE: Non-steroidal anti-inflammatory drugs (NSAIDs) are frequently used as the first-line agents for the symptomatic relief of rheumatoid arthritis (RA), but it may insidiously provoke the onset of renal diseases, especially chronic kidney disease (CKD). While Chinese herbal medicine (CHM) has become an increasingly popular adjunctive therapy among RA groups, there are currently no available data on the effect of CHM use towards risk of CKD. This study aimed to explore on a population-level whether CHM use decreases sequent CKD risk among them. METHODS: In this nested case–control study retrieved from the nationwide insurance database of Taiwan from 2000 to 2012, we looked at the association between CHM use and the likelihood of developing CKD, with a focus on usage intensity. Cases with CKD claims were defined and matched to one randomly selected control case. Conditional logistic regression was then applied to estimate odds ratio (OR) of CKD from CHM treatment measured before the index date. For each OR, we calculated a 95% confidence interval for CHM use relative to the matched control. RESULTS: This nested case–control study included 5464 patients with RA, where after matching comprised 2712 cases and 2712 controls. Among them, there were 706 and 1199 cases that ever received CHM treatment, respectively. After the adjustment, CHM use in RA individuals was related to a lower likelihood of CKD, with an adjusted OR of 0.49 (95% CI: 0.44–0.56). Additionally, a dose-dependent, reverse association was found between the cumulative duration of CHM use and risk of CKD. CONCLUSION: Integrating CHM into conventional therapy may reduce the likelihood of developing CKD, which could be a reference in instituting novel preventive strategies to improve treatment outcomes and reduce related fatalities for RA subjects.