Improvement in eGFR in patients with chronic kidney disease attending a nephrology clinic

Abstract

The adverse effects arising from late referral to a nephrologist of patients with chronic kidney disease (CKD) are well known. Retrospectively we examined the initial characteristics of patients referred in various stages of CKD to our nephrology division and tried to identify potential baseline factors associated with subsequent changes in estimated glomerular filtration rate (eGFR). Between September 1997 and June 2006 1,443 patients (909 male, 534 female) with CKD, with eGFRs ranging from 15 to 89 ml/min, were referred to our nephrology division and categorized using the National Kidney Foundation classification for CKD based on eGFR. The slope of eGFR change (ml/min-1/1.73/m2-1/year-1) was determined by linear regression analysis and the patients were divided into five groups: (1) significantly progressive slope (deterioration) (more negative than -5 ml/min/year); (2) mildly progressive slope (>-5 to <or=-1); (3) stable slope (>-1 to <or=+1); (4) mildly improved slope (>+1 to <or=+5), and (5) significantly improved slope (>or=+5). At the first nephrology referral, 5.8% of the patients were on CKD stage 2 (eGFR: 90-60 ml/m), 46.7% on CKD stage 3 (eGFR: 59-30 ml/m), and 47.5% on CKD stage 4 (eGFR: 29-15 ml/m) CKD. Significantly improved slope was detected in 48.2% of CKD stage 2 patients, 29.3% of CKD stage 3 patients, and only 14.7% of CKD stage 4 patients (P<0.05). Being in stage 4 or stage 3 versus being in stage 2 significantly reduced the likelihood of an improved slope in logistic regression analysis whereas age, gender, presence of hypertension, and diabetes mellitus did not reach the level of significance. Referral to a nephrology clinic can lead not only to arrest of progression of CKD but also to regression/improvement. Early referral is a positive predictive factor for improvement in eGFR, which emphasizes the importance of such referral. The previously held idea that, once established, CKD progresses invariably is not valid anymore.