The very elderly followed at a nephrology center: metabolic acidosis as a predictor of progressive chronic kidney disease

Abstract

Chronic kidney disease is an increasingly common diagnosis in the very elderly and identifying the patients who benefit from a nephrologist’s intervention and the ones who would not might avoid wasteful or harmful interventions. The aim of this study is to identify the risk factors for progressive versus non -progressive chronic kidney disease in a population aged over 80 years old. We performed a cohort single -center retrospective study including 101 patients over 80 years old with chronic kidney disease diagnosed for at least five years and followed regularly by a nephrologist. Progressive disease was defined as glomerular filtration rate declines greater than 5 mL/min/1.73 m2/year. Of the 101 patients, 33.7% had progressive chronic kidney disease. The median glomerular filtration progression rate was 3.0 [2.1 -6.0] mL/ min/1.73m2/year. Hypertension and diabetes mellitus prevalence was similar between groups. Nephrology follow -up time was longer in the progressive group (5.0 vs 2.0 years, p=0.01). Regarding chronic kidney disease complications, 37.6% had anemia and half of these needed erythropoiesis -stimulating agents. None of the patients had hyperphosphatemia. About 18.8% presented metabolic acidosis. In multivariable analysis, after adjusting for covariables such as age, hypertension, and diabetes mellitus only the presence of metabolic acidosis (OR 0.4, CI: 0.1 -0.8) was associated with the development of progressive chronic kidney disease. Progressive chronic kidney disease group presented higher mortality (log rank 4.5, p=0.03). Ischemic cardiomyopathy (OR: 0.5, CI: 0.2 -0.9) and progressive chronic kidney disease (OR: 0.6, CI:0.3 -0.8) were associated with all -cause mortality. Our results showed that most elderly patients have non -progressive chronic kidney disease. Patients with metabolic acidosis seem to be at an increased risk for developing progressive disease. Most elderly patients die before reaching end -stage kidney disease, so it is important to look at progressive kidney disease in those patients as an important marker of comorbidity and privilege cardioprotective measures.