Risk of ESRD and death in patients with CKD not referred to a nephrologist: a 7-year prospective study

Abstract

Background and objectives: Rising prevalence of CKD requires active involvement of general practitioners to limit ESRD and mortality risk. However, the outcomes of patients with CKD exclusively managed by general practitioners are ill defined.

Design, setting, participants, & measurements: We prospectively evaluated 30,326 adult patients with nondialysis CKD stages 1-5 who had never received consultation in tertiary nephrology care recruited from 700 general practitioner offices in Italy during 2002 and 2003. CKD stages were classified as stages 1 and 2 (GFR ≥ 60 ml/min per 1.73 m(2) and either albuminuria or an International Classification of Diseases, Ninth Revision, Clinical Modification code for kidney disease), stage 3a (GFR=59-45), stage 3b (GFR=44-30), stage 4 (GFR=29-15), and stage 5 (GFR<15). Primary outcome was the risk of ESRD (dialysis or transplantation) or all-cause death.

Results: Overall 64% of patients were in stage 3a, and 4.5% of patients were in stages 3b-5. Patients with stages 1 and 2 were younger, were predominantly men, more frequently had diabetes, and had lower prevalence of previous cardiovascular disease than patients with stages 3a-5. Hypertension was frequent in all CKD stages (80%-94%), whereas there was a lower prevalence of dyslipidemia, albuminuria, and obesity associated with more advanced CKD. During the follow-up (median=7.2 years; interquartile range=4.7-7.7), 6592 patients died and 295 started ESRD. Compared with stages 1 and 2 (reference), mortality risk (hazard ratio, 95% confidence interval) was higher in stages 3b-5 (1.66, 1.49-1.86, 2.75, 2.41-3.13 and 2.54, 2.01-3.22, respectively) but not stage 3a (1.11, 0.99-1.23). Similarly, ESRD risk (hazard ratio, 95% confidence interval) was not higher at stage 3a (1.44, 0.79-2.64) but was greater in stages 3b-5 (11.0, 6.3-19.5, 91.2, 53.2-156.2 and, 122.8, 67.9-222.0, respectively). Among modifiable risk factors, anemia and albuminuria significantly predicted either outcome, whereas hypertension only predicted mortality.

Conclusions: In patients with CKD not referred to nephrology, risks of ESRD and mortality were higher in those with CKD stages 3b-5.

Keywords: CKD; ICD-9-CM; codes; epidemiology and outcomes; mortality risk; risk factors.