Gout affects approximately 1 in 40 people and causes sudden and severe joint pain and swelling. These ‘flares’ most commonly affect the big toe. Flares are usually treated with medicines that reduce pain and swelling such as “anti-inflammatories”, colchicine, or steroid tablets. People with gout are also more likely to have kidney problems.
It is recommended that doctors weigh up the risks and benefits before deciding which drug to use in people with kidney problems who are having a gout flare. However, the guidelines don’t rule out any of the treatment options.
We want to design a study looking at whether giving people with kidney problems anti-inflammatories to treat a gout flare makes their kidney problems worse. If we found they did not, patients would benefit as more treatment choices would be available to them.
How well a person’s kidneys are working is measured using kidney function test. To plan our new study, we need to know how often this test is recorded in the medical notes of people with and without gout and with and without pre-existing kidney problems.
This study will use CPRD to look at the number of times kidney function is recorded in people:
- with gout but without kidney problems
- without gout but with kidney problems
- with both gout and kidney problems
- without either gout or kidney problems
We will look at this over all the time in their medical record and immediately before and after gout flares diagnosed in primary care.
Background
Gout is the most common inflammatory arthritis affecting 2.5% of UK adults. Acute flares cause significant pain and impaired quality of life.
Flares require rapid treatment with nonsteroidal anti-inflammatory drugs (NSAIDs), colchicine or corticosteroids. NSAIDs cause significant potential adverse events, accounting for 30% of adverse drug reaction-related hospital admissions.
Gout is associated with comorbid conditions, including chronic kidney disease (CKD). CKD is categorised using estimated glomerular filtration rates (eGFR), calculated from the creatinine value. Gout guidelines highlight potential nephrotoxicity of NSAIDs and advise taking CKD into account before prescribing NSAIDs, but do not explicitly contra-indicate their use.
Aim
To perform a feasibility study into rates of recording of eGFR (or creatinine) in people with and without gout and with and without CKD in preparation for a larger study about NSAIDs in people with gout.
Objectives
Assess the rate of eGFR (or creatinine) measurements per year in four patient groups:
with gout and no history of CKD
without gout, but with a history of CKD
with gout and a history of CKD
without either gout or a history of CKD
Assess whether this rate increases in the 3 months before/after a gout flare.
Methods
Four cohorts in CPRD Aurum, aged 18+ years with gout and/or CKD and a random sample of people with neither condition. Proportions and rates of individuals with recorded eGFR/creatinine measurements will be calculated in each of the 4 cohorts overall, in sociodemographic subgroups and in the periods immediately before/after a gout flare.
Primary care data will be linked to indices of multiple deprivation to allow investigation of differential eGFR/creatine recording by deprivation.
This study will inform a larger study that aims to inform better guidance for the treatment of gout, in relation to kidney health.
eGFR (recorded or calculated from creatinine)
Richard Partington - Chief Investigator - Keele University
Sara Muller - Corresponding Applicant - Keele University
Abhishek Abhishek - Collaborator - University of Nottingham
Christian Mallen - Collaborator - Keele University
Edward Roddy - Collaborator - Keele University
James Bailey - Collaborator - Keele University
Mark Lambie - Collaborator - Keele University
Patient Level Index of Multiple Deprivation