Uric acid is not associated with decline in renal function or time to renal replacement therapy initiation in a referred cohort of patients with Stage III, IV and V chronic kidney disease.
Although many studies have suggested an association between higher uric acid (UA) and both development of chronic kidney disease (CKD) and faster decline in renal function in Stage I and II CKD, it is not clear whether this effect is consistent throughout higher CKD stages. The aim of this study was to investigate the association between baseline UA and renal outcomes in patients with established CKD (Stages III-V).
We analysed data in the Swedish Renal Registry-Chronic Kidney Disease (SRR-CKD), which is a nationwide registry of referred CKD patients. Patients with a visit between January 1(st), 2005 and December 31(st), 2011 were followed until initiation of renal replacement therapy (RRT), death, referral to primary care or end of follow-up. Decline in renal function was assessed with a linear mixed model using all estimated glomerular filtration rate (eGFR) assessments recorded during median 28 months of follow-up, adjusting for important confounders such as demographic factors, primary renal disease, age, sex, relevant medication, diet, blood pressure and body mass index.
There were 2466 patients with a baseline UA measurement {mean [standard deviation (SD)] of 7.81 [1.98] mg/dL}. The mean decline in renal function was -1.48 (95% CI -1.65; -1.31) mL/min/1.73 m(2) per year. The overall adjusted change in decline in renal function per unit increase in baseline UA was 0.08 (95% CI -0.01; 0.17) mL/min/1.73 m(2) per year indicating no association between higher UA levels and decline in renal function. In Stage III, IV and V CKD patients, the mean decline in renal function was -1.52 (95% CI -1.96; -1.08), -1.52 (95% CI -1.72; -1.32) and -1.19 (95% CI -1.75; -0.64) mL/min/1.73 m(2) per year, respectively. The adjusted change in the decline in renal function per unit increase in baseline UA was -0.09 (95% CI -0.30; 0.13) in Stage III CKD, 0.16 (95% CI 0.04; 0.28) in Stage IV CKD and 0.18 (95% CI -0.09; 0.45) in Stage V CKD. The overall adjusted hazard ratio for start of RRT was 0.97 (95% CI 0.93-1.02). For Stage III, IV and V CKD, it was 0.99 (95% CI 0.73-1.34), 0.97 (95% CI 0.91-1.03) and 0.99 (95% CI 0.91-1.07), respectively.
UA is not associated with the rate of decline in renal function or time to start of RRT in Stage III, IV and/or V CKD patients.
Nacak H
,van Diepen M
,Qureshi AR
,Carrero JJ
,Stijnen T
,Dekker FW
,Evans M
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Factors associated with kidney disease progression and mortality in a referred CKD population.
Knowing how kidney disease progresses is important for decision making in patients with chronic kidney disease (CKD) and for designing clinical services.
Prospective cohort study.
We examined renal function trajectories in CRISIS (Chronic Renal Insufficiency Standards Implementation Study), in which 1,325 patients with CKD stages 3-5 and mean age of 65.1 years were followed up prospectively for a median of 26 months after referral to a regional nephrology center in the United Kingdom. By protocol, estimated glomerular filtration rate was determined every 12 months.
CKD stage defined as estimated glomerular filtration rate ≥ 45 (stage 3a), 30-44 (3b), 15-29 (4), and < 15 (5) mL/min/1.73 m².
Onset of renal replacement therapy (RRT), death, the composite end point of RRT or death, or decreasing CKD stage.
During a median follow-up of 26 months, 13% reached the end point of RRT (5.1 events/100 patient-years), 20% died (9.6 deaths/100 patient-years), and 33% reached the combined end point of RRT or death (14.7 events/100 patient-years). For stage 3a, baseline prevalence and annual probabilities of decreasing CKD stage, RRT, and death were 18.0%, 0.41, 0.01, and 0.02, respectively. Corresponding values for stage 3b were 32.5%, 0.22, < 0.01, and 0.06; for stage 4, 36.5%, 0.17, 0.03, and 0.10; and for stage 5, 13.2%, zero (by definition), 0.31, and 0.08, respectively. Markov model projections suggested a steady decrease for proportions with stages 3a, 3b, and 4; a steady increase for death and RRT; and a biphasic pattern for (non-RRT) stage 5, with a plateau in the first 2 years followed by a steady decrease.
Single-center observational study.
This study suggests that death and RRT are the dominant outcomes in patients referred for management of CKD and that most patients spend comparatively little time in late stages without RRT.
Hoefield RA
,Kalra PA
,Baker P
,Lane B
,New JP
,O'Donoghue DJ
,Foley RN
,Middleton RJ
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