Does oral sodium bicarbonate therapy improve function and quality of life in
older patients with chronic kidney disease and low-grade acidosis (the BiCARB
trial)? Study protocol for a randomized controlled trial.
Author(s): Witham MD(1), Band MM(2), Littleford RC(3), Avenell A(4), Soiza RL(5), McMurdo
ME(6), Sumukadas D(7), Ogston SA(8), Lamb EJ(9), Hampson G(10), McNamee P(11);
BiCARB study group.
Affiliation(s): Author information:
(1)Medical Research Institute, University of Dundee, Ninewells Hospital, Dundee,
DD1 9SY, UK. m.witham@dundee.ac.uk. (2)Tayside Clinical Trials Unit, University
of Dundee / NHS Tayside, Dundee, UK. m.band@dundee.ac.uk. (3)Tayside Clinical
Trials Unit, University of Dundee / NHS Tayside, Dundee, UK.
r.littleford@dundee.ac.uk. (4)Health Services Research Unit, University of
Aberdeen, Aberdeen, UK. a.avenell@abdn.ac.uk. (5)Health Services Research Unit,
University of Aberdeen, Aberdeen, UK. r.l.soiza@abdn.ac.uk. (6)Medical Research
Institute, University of Dundee, Ninewells Hospital, Dundee, DD1 9SY, UK.
m.e.t.mcmurdo@dundee.ac.uk. (7)Medical Research Institute, University of Dundee,
Ninewells Hospital, Dundee, DD1 9SY, UK. d.sumukadas@dundee.ac.uk.
(8)Epidemiology and Biostatistics Unit, University of Dundee, Dundee, UK.
s.a.ogston@dundee.ac.uk. (9)Department of Clinical Biochemistry, East Kent NHS
Trust, Canterbury, UK. elamb@nhs.net. (10)Department of Chemical Pathology, Guy's
and St Thomas' Hospitals, London, UK. geeta.hampson@kcl.ac.uk. (11)Health
Economics Research Unit, University of Aberdeen, Aberdeen, UK.
p.mcnamee@abdn.ac.uk.
Publication date & source: 2015, Trials. , 16:326
BACKGROUND: Metabolic acidosis is more common with advancing chronic kidney
disease, and has been associated with impaired physical function, impaired bone
health, accelerated decline in kidney function and increased vascular risk.
Although oral sodium bicarbonate is widely used to correct metabolic acidosis,
there exist potential risks of therapy including worsening hypertension and fluid
overload. Little trial evidence exists to decide whether oral bicarbonate therapy
is of net benefit in advanced chronic kidney disease, particularly in older
people who are most commonly affected, and in whom physical function, quality of
life and vascular health are at least as important outcomes as decline in renal
function.
METHODS/DESIGN: BiCARB is a multi-centre, double-blind, placebo controlled,
randomised trial evaluating the clinical and cost-effectiveness of oral sodium
bicarbonate in the management of older people with chronic kidney disease and
severely reduced glomerular filtration rate (GFR) who have a mild degree of
metabolic acidosis. The trial will recruit 380 patients from renal, Medicine for
the Elderly, and primary care services across centres in the United Kingdom. Male
and female patients aged 60 years and older with an estimated glomerular
filtration rate of <30 mL/min/1.73 m(2), not on dialysis, and with serum
bicarbonate concentrations <22 mmol/L will be eligible for participation. The
primary clinical outcome for the trial is the between-group difference in the
Short Physical Performance Battery score at 12 months. Secondary outcomes include
muscle strength, quality of life measured using the EQ-5D score and KDQoL tools,
cost effectiveness, renal function, presence of albuminuria and blood pressure.
Markers of bone turnover (25-hydroxyvitamin D, 1,25-hydroxyvitamin D,
tartrate-resistant acid phosphatase-5b and bone-specific alkaline phosphatase)
and vascular health (B-type natriuretic peptide) will be measured. Participants
will receive a total of 24 months of either bicarbonate or placebo. The results
will provide the first robust test of the overall clinical and cost-effectiveness
of this commonly used therapy in older patients with severely reduced kidney
function.
TRIAL REGISTRATION: www.isrctn.com ; ISRCTN09486651 , registered 17 February
2012.
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