Risk factors for progression in KDOQI stage 3 Chronic Kidney Disease (PROGRESER study)

Introduction: The PROGRESER study is a multicentre, prospective, observational, 3-year follow-up study of a cohort of patients with stage 3 chronic kidney disease (CKD) from different nephrology departments of hospitals in the Spanish healthcare system. The primary study objective was to analyse risk factors for CKD progression, identifying possible differences between patients with and without diabetes mellitus (DM). The secondary objective was to analyse the factors associated with hospitalizations and mortality. Patients and methods: A total of 462 patients (342 men and 120 women; mean age 66.5 +/- 11.5 years) were recruited from 25 participating sites in Spain. Clinical, epidemiological and analytical data were recorder in an electronic register each six months. Biological samples were obtained and frozen for a biobank record at baseline and at 18 and 36 months. Results: The initial mean glomerular filtration rate estimated by MDRD and after that reestimated by CKD-EPI was 43.9 +/- 7.9 mL/min/1.73 m(2); and 29 +/- 6,8 mL/min/1,73 m(2) at 3 years. 27.3% of patients had microalbuminuria and 22.5% had macroalbuminuria. Two-thirds of the patients (66.2%) presented renal damage progression according to the study criteria (decrease of more than 15% in eGFR over the baseline value). 38.7% presented a reduction in eGFR >= 30%; 20.3% had a reduction in eGFR >= 40%; 10.4% had a reduction >= 50% and 6.9% had a reduction >= 57%. Of the 199 diabetics, 134 (67.3%) suffered renal damage progression. Of the 263 non-diabetics, 172 (65.3%) presented progression (P = .456). 27.3% of patients had microalbuminuria and 22.5% proteinuria. The study found that CKD progression to a higher stage was not greater in diabetic compared to non-diabetic patients. Multivariate analysis revealed that the presence of arterial hypertension bordered on significance as a progression factor in non-diabetic patients (P = .07), and that, in diabetic patients, lower calcium levels and elevated intact parathyroid hormone levels at baseline were associated with progression. Conclusion: In our study we have not found new factors for progression of renal damage, different from the yet well known traditional factors. DM per se was not a differential factor for progression in relation with non DM patients. Progression of renal damage in patients with CKD-3 KDOQI may be interpreted in a multifactorial context. The search for new biomarkers, different from traditional ones, is necessary to establish new therapeutic strategies to prevent the progression of CKD.