title: 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, end-stage 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 using multivariate Cox proportional hazards regression models. 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 ± 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-high-risk 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 increased mortality in RA patients.
authors.affiliation: Department IV of Internal Medicine, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Tokoroyama
authors.affiliation: Department IV of Internal Medicine, Tokyo Women's Medical University, Tokyo, Japan.|Department of Medicine, Tokyo Metropolitan Fu-chu Medical and Welfare Center, 2-9-2, Musashidai, Fu-chu City, Tokyo 183-8553, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Ando
authors.affiliation: Division of Collagen Disease, Department of Medicine, Tokyo Metropolitan Komagome Hospital, Bunkyo, Tokyo 113-0021, Japan.
authors.forename: Kyogo
authors.initials: K
authors.lastname: Setoguchi
authors.affiliation: Department IV of Internal Medicine, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Tsuchiya
authors.affiliation: Department IV of Internal Medicine, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: Kosaku
authors.initials: K
authors.lastname: Nitta
mesh_terms: D000368:Aged; D001172:Arthritis, Rheumatoid / Q000150:complications*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D017410:Practice Guidelines as Topic / Q000592:standards*; D015995:Prevalence; D011379:Prognosis; D051436:Renal Insufficiency, Chronic / Q000145:classification / Q000453:epidemiology* / Q000209:etiology / Q000401:mortality*; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate
keywords: estimated glomerular filtration rate; mortality; proteinuria; risk category