15-year-change of phenotype and prognosis in non-dialysis CKD patients referred to a nephrology clinic

Abstract

Purpose: Changes over time of phenotype and prognosis in CKD patients starting nephrology care are undefined. This information is critical to correctly plan and optimize healthcare resources and clinical management in tertiary care.

Methods: We performed a long-term observational cohort study including 2,866 non-dialysis CKD patients newly referred to our nephrology clinic from 2004 to 2018. Three cohorts were constituted based on 5-year calendar intervals (2004-2008, 2009-2013, and 2014-2018). The changes over time of main demographic, clinical and laboratory characteristics were compared among the three cohorts. We also compared between cohorts the risk of renal death (combined endpoint of renal replacement therapy-RRT, or death before RRT) as well as of the single components (RRT or death).

Results: Across the three cohorts, we detected a significant increase in the prevalence of age ≥ 75 years (from 22.0 to 28.4%), male gender (from 53.1 to 62.1%), diabetes (from 32.6 to 39.5%), severe proteinuria ≥ 500 mg/24 h (from 46.9 to 52.4%). Mean eGFR at referral declined from 56.8 ± 27.0 to 49.6 ± 26.1 mL/min/1.73m². Incidence of renal death significantly declined over time (5.36, 3.22 and 4.54/100 pts-year in 2004-2008, 2009-2013 and 2014-2018 cohorts, respectively). As compared with patients referred in 2004-2008, adjusted risk of renal death was lower in patients referred in 2009-2013 (HR 0.49, 95%CI 0.34-0.69) and 2014-2018 (HR 0.61, 95%CI 0.45-0.84). Similar results were obtained for RRT, while mortality did not change over time.

Conclusions: In the last 15 years, phenotype of newly referred CKD patients has remarkably changed with increasing frequency of older patients and more severe disease; however, renal survival improved suggesting greater efficacy of nephrology care.

Keywords: CKD; Nephrology care; Nephrology referral; Proteinuria/albuminuria; eGFR.