Prevalence of and factors associated with renal dysfunction in rheumatoid arthritis patients: a cross-sectional study in community hospitals

This study was designed to determine the prevalence of renal dysfunction in rheumatoid arthritis (RA) patients and to identify factors associated with this complication. Between October 2014 and May 2015, we consecutively recruited RA patients at rheumatology sections of community hospitals in Japan. Each patient's absolute and body surface area (BSA)-indexed estimated glomerular filtration rate (eGFR) values were measured twice over a 3-month interval. Renal dysfunction was defined as absolute eGFR or BSA-indexed eGFR < 60. Albuminuria and hematuria were also recorded. Associations between renal dysfunction and possible risk factors were examined by multivariate logistic regression analyses. A total of 1908 outpatients with RA were included in this study. The prevalence of renal dysfunction based on absolute eGFR and BSA-indexed eGFR was 33.8 and 18.6%, respectively. Albuminuria was observed in 8.1% of this patient cohort, and the prevalence of hematuria was 7.5%. Advanced age (odds ratio [OR] 7.24, p < 0.001), female sex (OR 3.12, p < 0.001), hypertension (OR 2.22, p < 0.001), and obesity (OR 0.59, p < 0.001) were independently associated with the risk of absolute eGFR-based renal dysfunction. Advanced age (OR 5.19, p < 0.001) and hypertension (OR 3.05, p < 0.001) also had associations with BSA-indexed eGFR-based renal dysfunction. RA duration, stages, severity, and cumulative steroid dose were considered significant risk factors in univariate analyses, but their associations were less potent after adjustment for other covariates. Renal dysfunction is relatively common in RA patients and is mainly associated with advanced age and hypertension but not with RA-related factors.