Z Wang1,2, J Zhang1,2, O Adegbija1,2, R Abeysekera1,3, HG Healy1,3, KS Tan1,2,4, A Cameron1,2,3, WE Hoy1,2
1 NHMRC CKD.CRE and CKD.QLD, Brisbane, Queensland; 2UQCCR, University of Queensland (UQ), Brisbane, Queensland; 3Kidney Health Service (RBWH); Metro North Hospital and Health Service, Brisbane, Queensland; 4Renal Services (Logan), Metro South Hospital and Health Service, Brisbane, Queensland
Aim: To determine predictors associated with kidney disease progression.
Background: The CKD.QLD registry commenced incremental patient recruitment mid-2011 with CKD patients followed for disease progression and endpoints of death and/or initiation of renal replacement therapy (RRT).
Methods: In this observational longitudinal cohort study, subjects were patients with CKD, enrolled in the registry, and attending renal clinics in two major public hospitals in Queensland, Australia. Primary endpoints were the first of either an absolute 30% decline in eGFR (CKD-EPI) at 2 years, death or starting RRT. Proteinuria/albuminuria was defined by three categories using protein-to-creatinine ratio (PCR)/ albumin-to-creatinine ratio (ACR), or protein dipstick. Cox regression models were applied to test associations of significance.
Results: 1,052 patients of those with eGFR at consent<60 ml/min/1.73m2 were eligible (females 47.5%). Age at consent ranged 18 to 99 years, mean 68 (median 71) years. At two years, eGFR was reduced by>30% in 11% (n=106) of 937 patients who had that repeat measurement. 4.2% (n=49) and 6.3% (n=66) of 1,052 had died or commenced RRT respectively. A total of 221 (21%) reached the composite primary endpoint. Associations of independent significance (HR, 95%CI) were: age<70 years 1.4 (1.02-1.93), diabetic nephropathy (DN) 2.49 (1.19-5.22) and genetic renal disease (GRD) 3.35 (1.44-7.79), with glomerular nephritis (GN) a reference group, micro-proteinuria/albuminuria, 1.76 (1.03-3.0) ,and macro- proteinuria/albuminuria, 4.69 (2.9-7.59), with “normal” PCR or ACR or negative dipstick as the reference group.
Conclusions: The majority of patients with CKD did not progress by this definition. Of those who did, age<70 years, the presence of DN, GRD and proteinuria/albuminuria, both micro- and macro-, were powerful independent predictors of progression of kidney disease.