Natural history of CKD stage 4 and 5 patients following referral to renal management clinic.

BACKGROUND: CKD patients referred to a renal management clinic are looked after by a multidisciplinary team whose care may improve outcome and delay the progression of kidney disease. This paper describes our experience and the results obtained in 940 patients with CKD stage 4 and 5 patients from two renal management clinics (RMC).

SUBJECTS AND METHODS: We collected and analyzed the data from 940 patients with CKD stage 4 and 5 at the RMCs of the Toronto General Hospital (TGH), University Health Network and The Scarborough General Hospital (TSH) from January 2000 to November 2007. Inclusion criteria for the study required at least three measurements of serum creatinine over a minimum follow-up of 6 months. We calculated the change of slope of the estimated GFR by linear regression analysis. The slopes were further subdivided into five groups: improved eGFR (eGFR slope >or=+5 ml/min/year); mild improvement (slope >+1 to <+5 ml/min/year); stable (slope <+1 to >-1 ml/min/year); slow progression (i.e., deterioration; slope <-1 to >-5 ml/min/year) and rapid progression (slope >-5 ml/min/year).

RESULTS: During a median follow-up of 1.57 year (range 0.5-8.7 year) of stage 4 patients, eGFR improved in 10.6%, showed mild improvement in 24.2%, was stable in 27.5%, showed slow progression in 28.8% and rapid progression in 8.9% of patients. During a median follow-up of 1.4 year (range 0.5-8 year) of CKD stage 5 patients, eGFR improved in only 1.3%, showed mild improvement in 4.3%, remained stable in 35.6%; showed slow progression in 19.7% and rapid progression in 39.1%. Between the two hospitals (TGH and TSH) there was a statistically significant difference in the number of visits per year for CKD stage 4 patients during the first, second and third year. However, the number of visits per year had no effect on the rate of decline. On univariate analysis, factors predicting non-progression in eGFR slope were eGFR at referral, the use of ACE inhibitors-ARBs and absence of cardiovascular disease. However, in logistic multivariate regression analysis, after adjusting for confounding factors only the eGFR at referral and ACE inhibitors-ARBs were independent factors for non-progression in eGFR. A significant percentage of CKD stage 4 patients attending a renal management clinic (RMC) showed non-progression or improvement in their kidney function. Although only few stage 5 CKD patients had improvement in their eGFR, 32% of them maintained their eGFR on conservative treatment for over 2 years delaying the initiation of dialysis.