Prevalence, incidence and prognosis of chronic kidney disease classified according to current guidelines: A large retrospective cohort study of rheumatoid arthritis patients

Abstract

Background. The prevalence, incidence and prognosis of chronic kidney disease (CKD) have not been fully understood in rheumatoid arthritis (RA) patients. Methods. A retrospective cohort study was performed in 1077 RA patients from July 2004 to June 2014. CKD was defined as either proteinuria -1 or estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 or both, according to the current CKD classification with risk categories for future death, endstage renal disease and cardiovascular disease. The cumulative incidence of mortality and CKD was analyzed using the Kaplan-Meier method. The association of each outcome with known risk factors was analyzed usingmultivariate Cox proportional hazards regressionmodels. Hazard ratios (HRs) with 95% confidence intervals (CIs) for mortality and incidence of CKD were calculated for estimation. Results. The mean follow-up period was 51.5 6 39.6 months, and the cumulative mortality was 20.6% over 10 years. The prevalence of any CKD was 24.5% at enrollment. Preexisting CKD was significantly associated with future death [HR 1.64 (95% CI 1.05-2.57)]. This association was the most robust in very-highrisk CKD [HR 4.76 (95% CI 2.24-9.51)]. The cumulative incidence of CKD over time was 59.5% in 813 patients who did not have prior CKD. Aside from the commonly known risk factors, the use of prednisolone and nonsteroidal anti-inflammatory drugs increased the likelihood of death [HR 1.75 (95% CI 1.11-2.79)] and incident CKD [HR 1.44 (95% CI 1.13-1.86)]. Conclusions. The incidence of CKD increases over time among RA patients and prevalent CKD may be an insidious risk factor linked to increasedmortality in RA patients.