Natural History of Older Adults with Impaired Kidney Function: The InCHIANTI Study

The aim of this study was to assess the kidney function of an older community-dwelling population at baseline and appraise its evolution after 3 years of follow-up in terms of chronic kidney disease (CKD) stage progression, magnitude of glomerular filtration rate (GFR) changes, and value of serum creatinine. This was a prospective population-based study of 676 Italian participants, aged 65 years and older. GFR was estimated using the Cockcroft-Gault equation and the Modification of Diet in Renal Disease Study equation. Using the Cockcroft-Gault equation. A total of 33% of participants had criteria of CKD (GFR < 60 mL/min) at baseline; among them, the majority remained stable, 10% improved, and 7% progressed to more severe CKD stages at follow-up. Loss of GFR in participants with GFR < 60 mL/min was significantly lower (1.4 mL/min per year) than in participants with GFR >= 60 mL/min (3.3 mL/min per year) at baseline. Most participants classified with CKD stage 2 (GFR 60-89 mL/min) or stage 3 (GFR 30-59 mL/min) at baseline did not change stage, whereas 55% of people with CKD stage 1 (GFR > 90 mL/min) at baseline worsened to stage 2 and 10% worsened to stage 3. An abnormal high level of serum creatinine at baseline did not help to predict who might worsen at follow-up. Older people with CKD displayed a low progression of renal disease and therefore are at higher risk for comorbidities related to CKD than for progression to end-stage renal disease.