Combining GFR and Albuminuria to Classify CKD Improves Prediction of ESRD

Abstract

Despite the high prevalence of chronic kidney disease (CKD), relatively few individuals with CKD progress to ESRD. A better understanding of the risk factors for progression could improve the classification system of CKD and strategies for screening. We analyzed data from 65,589 adults who participated in the Nord-Trøndelag Health (HUNT 2) Study (1995 to 1997) and found 124 patients who progressed to ESRD after 10.3 yr of follow-up. In multivariable survival analysis, estimated GFR (eGFR) and albuminuria were independently and strongly associated with progression to ESRD: Hazard ratios for eGFR 45 to 59, 30 to 44, and 15 to 29 ml/min per 1.73 m 2 were 6.7, 18.8, and 65.7, respectively (P Ͻ 0.001 for all), and for micro-and macroalbuminuria were 13.0 and 47.2 (P Ͻ 0.001 for both). Hypertension, diabetes, male gender, smoking, depression, obesity, cardiovascular disease, dyslipidemia, physical activity and education did not add predictive information. Time-dependent receiver operating characteristic analyses showed that considering both the urinary albumin/creatinine ratio and eGFR substantially improved diagnostic accuracy. Referral based on current stages 3 to 4 CKD (eGFR 15 to 59 ml/min per 1.73 m 2 ) would include 4.7% of the general population and identify 69.4% of all individuals progressing to ESRD. Referral based on our classification system would include 1.4% of the general population without losing predictive power (i.e., it would detect 65.6% of all individuals progressing to ESRD). In conclusion, all levels of reduced eGFR should be complemented by quantification of urinary albumin to predict optimally progression to ESRD.

Impact of Age and Overt Proteinuria on Outcomes of Stage 3 to 5 Chronic Kidney Disease in a Referred Cohort

“…As shown in the present study, proteinuria and age contributed differently to CKD outcomes. Proteinuria and albuminuria are accepted markers of kidney damage, and are associated with lower eGFR and an increased risk of subsequent ESRD (31)(32)(33)(34)(35)(36)(37)(38)(39). On the other hand, age is inversely associated with ESRD and positively associated with death (7,40 -43).…”

Dipstick Proteinuria as a Screening Strategy to Identify Rapid Renal Decline

“…Importantly, Matsushita et al 5 observed an increased risk for CVD and all-cause mortality from RKFD in those with eGFR 60 to 90 ml/min per 1.73 m 2 at baseline, and other studies of the general population show an increased risk for adverse outcomes from RKFD or proteinuria independently of baseline eGFR. 4,6,13,14 Although albuminuria has greater sensitivity at low levels and is the recommended method for monitoring proteinuria in diabetics, [15][16][17] we show that dipstick urinalysis, an inexpensive test that is already a common feature of primary care, has better diagnostic utility for identifying RKFD.…”

“…In contrast, the meaning of RKFD at eGFR Ͼ90 ml/min per 1.73 m 2 is less clear because there is no body of evidence documenting adverse outcomes in this group. 19 Although previous research has established that proteinuria in the presence of eGFR Ͻ60 ml/min per 1.73 m 2 is a stronger risk factor for CVD and ESRD than either indicator alone, 13,20 serial eGFR assessment would provide additional information about a patient's risk trajectory. For example, in elderly patients with reduced but stable kidney function, a low eGFR (30 to 60 ml/min per 1.73 m 2 ) may be an indicator of age-related comorbidity rather than vascular pathology, the latter being responsive to treatment with angiotensin-receptor blockers if caused by proteinuria.…”

Lack of association between anemia and renal disease progression in Chinese patients with type 2 diabetes

“…Anemia is common in diabetes patients with nephropathy, and its severity worsens with more advanced stage of CKD and proteinuria2. At the same time, low estimated glomerular filtration rate (eGFR) and high urine albumin are two major risk factors for ESRD with strong predictive powers15. More proof is still awaited on the relationships among anemia, nephropathy and progression of renal disease.…”