104 Oral Sodium Bicarbonate Therapy for Older Patients with Chronic Kidney Disease and Low-Grade Acidosis: The BiCARB Randomised Controlled Trial

Background Oral sodium bicarbonate is often used to treat metabolic acidosis in older people with advanced chronic kidney disease, but evidence is lacking on whether this provides a net gain in health or quality of life. Methods We conducted a multicentre, parallel group, double-blind, placebo-controlled randomised trial. Adults aged 60 years and over with category 4 or 5 chronic kidney disease, not on dialysis, with serum bicarbonate concentrations <22 mmol/L were recruited from 27 UK centres. Participants were randomised 1:1 to oral sodium bicarbonate or matching placebo. The primary outcome was the between-group difference in the Short Physical Performance Battery at 12 months, adjusted for baseline. Other key outcome measures included generic and disease-specific health-related quality of life, anthropometry, physical performance, renal function, adverse events including commencement of renal replacement therapy, and health economic analysis. Results We randomised 300 participants, mean age 74 years; 86 (29%) were female. Mean baseline estimated GFR was 19 ml/min/1.73m2. Study medication adherence was 73% in both groups. No significant treatment effect was evident for the primary outcome of the between-group difference in the Short Physical Performance Battery at 12 months (-0.4 points; 95% CI -0.9 to 0.1, p=0.15). No significant treatment benefit was seen for any of the secondary outcomes. Adverse events were more frequent in the bicarbonate arm (457 versus 400). Time to commencing renal replacement therapy was similar in both groups (HR 1.22, 95% CI 0.74 to 2.02, p=0.43). Health economic analysis showed lower quality of life and higher costs in the bicarbonate arm at one year (£1234 vs £807); placebo dominated bicarbonate under all sensitivity analyses for incremental cost-effectiveness. Conclusions Oral sodium bicarbonate did not improve a wide range of health measures in this trial, and is unlikely to be cost-effective for use in the UK NHS in this patient group.