Clinical and cost-effectiveness of oral sodium bicarbonate therapy for older patients with chronic kidney disease and low-grade acidosis (BiCARB): a pragmatic randomised, double-blind, placebo-controlled trial

BiCARB Study Group

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)
8 Downloads (Pure)


BackgroundChronic kidney disease with metabolic acidosis is common in older people, but the effectiveness of oral sodium bicarbonate therapy in this group is unclear. We tested whether oral sodium bicarbonate provides net health benefit for older people with advanced chronic kidney disease and serum bicarbonate concentrations < 22 mmol/L.MethodsPragmatic multicentre, parallel group, double-blind, placebo-controlled randomised trial. We recruited adults aged ≥ 60 years with estimated glomerular filtration rate of < 30 mL/min/1.73 m2, not receiving dialysis, with serum bicarbonate concentration < 22 mmol/L, from 27 nephrology and geriatric medicine departments in the UK. Participants received oral sodium bicarbonate (up to 3 g/day) or matching placebo given for up to 2 years, randomised in a 1:1 ratio. The primary outcome was between-group difference in the Short Physical Performance Battery (SPPB) at 12 months, adjusted for baseline values, analysed by intention to treat. Secondary outcomes included generic and disease-specific quality of life (EQ-5D and KDQoL tools), anthropometry, renal function, walk distance, blood pressure, bone and vascular health markers, and incremental cost per quality-adjusted life year gained.ResultsWe randomised 300 participants between May 2013 and February 2017, mean age 74 years, 86 (29%) female. At 12 months, 116/152 (76%) participants allocated to bicarbonate and 104/148 (70%) allocated to placebo were assessed; primary outcome data were available for 187 participants. We found no significant treatment effect for the SPPB: bicarbonate arm 8.3 (SD 2.5) points, placebo arm 8.8 (SD 2.2) and adjusted treatment effect − 0.4 (95% CI − 0.9 to 0.1, p = 0.15). We found no significant treatment effect for glomerular filtration rate (0.6 mL/min/1.73 m2, 95% CI − 0.8 to 2.0, p = 0.39). The bicarbonate arm showed higher costs and lower quality of life as measured by the EQ-5D-3L tool over 1 year (£564 [95% CI £88 to £1154]); placebo dominated bicarbonate under all sensitivity analyses. Adverse events were more frequent in those randomised to bicarbonate (457 versus 400).ConclusionsOral sodium bicarbonate did not improve physical function or renal function, increased adverse events and is unlikely to be cost-effective for use by the UK NHS for this patient group.Trial registration European Clinical Trials Database (2011-005271-16) and ISRCTN09486651; registered 17 February 2012.
Original languageEnglish
Article number91
Number of pages16
JournalBMC medicine
Publication statusPublished - 9 Apr 2020

Bibliographical note

We acknowledge the support received via the NHS Scotland Support for
Science scheme; the NIHR Renal and Ageing Comprehensive Research
Networks; and the work of all of the research nurses, local investigators and
study teams at sites; Tayside Clinical Trials Unit staff; and most importantly all
those with kidney disease who participated in the trial. Professor Witham
acknowledges support from the NIHR Newcastle Biomedical Research Centre.
In addition, we acknowledge the support and advice we received from the
independent Trial Steering Committee members (Professor David Stott,
Professor Patrick Mark, Professor Tahir Masud and Mr. Alex Stephen) and the
independent Data Monitoring Committee (Professor Alex McConnachie,
Professor David Wheeler, Dr. Nicosha de Souza, Professor Andrew Clegg). We
also acknowledge the efforts of all the investigators, site research nurses and
support teams.

The BiCARB trial was funded by the National Institute for Health Research
Health Technology Assessment programme (project reference 10/71/01). The
views expressed are those of the authors and not necessarily those of the
NIHR or the Department of Health and Social Care.
The funder of the study had input into the study design via the original
commissioning call specification. The funder had no other role in the study
design, data collection, data analysis, data interpretation, or writing of the
report. The corresponding author had full access to all the data in the study
and had final responsibility for the decision to submit.
Disclaimer: The Health Services Research Unit and Health Economics
Research Unit are core funded by the Chief Scientist Office of the Scottish
Government Health and Social Care Directorate.


  • sodium bicarbonate
  • renal insufficiency
  • chronic
  • Acidosis
  • randomised controlled trial


Dive into the research topics of 'Clinical and cost-effectiveness of oral sodium bicarbonate therapy for older patients with chronic kidney disease and low-grade acidosis (BiCARB): a pragmatic randomised, double-blind, placebo-controlled trial'. Together they form a unique fingerprint.

Cite this