medwireNews: A large cohort study from the UK has confirmed that the risk for gout is increased in people with obstructive sleep apnea (OSA), and shows that the risk peaks 1–2 years after diagnosis.
The study included 15,879 individuals with OSA and 63,296 without OSA from the UK Clinical Practice Research Datalink, matched for age, sex, and the primary care clinic they attended.
Over a median follow-up of 5.8 years, 782 (4.9%) of those with OSA developed gout, compared with 1651 (2.6%) of those without OSA. The incidence per 1000 person–years was 7.83 and 4.03, respectively, with OSA patients having a significant 1.42-fold increased risk for gout after adjustment for potentially confounding factors including age, sex, and BMI.
And the increased risk for gout among people with OSA was seen in all body mass index (BMI) categories. In fact, the risk was highest in those with a normal BMI (<25 kg/m2), with a significant hazard ratio of 1.76, relative to people without OSA of a similar BMI. This compared with 1.27 and 1.40, respectively, for those who were overweight (BMI=25 to <30 kg/m2) or obese (BMI≥30 kg/m2).
“This suggests that the contribution of OSA to the risk of hyperuricaemia and gout is independent of BMI and clinicians should consider the possibility of gout in patients with sleep apnea regardless of obesity,” write Milica Blagojevic-Bucknall (Keele University, UK) and colleagues in Arthritis & Rheumatology.
The team notes that people with OSA have previously been shown to have a higher risk for developing gout in the first year after OSA diagnosis, but they found that the increased risk persists beyond this point, with the highest risk for incident gout – a 1.64-fold increase – seen at 1–2 years after diagnosis.
Among the different BMI categories, the increased risk among individuals with OSA remained highest at 1–2 years after diagnosis in those who were overweight and obese, with significant hazard ratios of 1.73 and 1.70, respectively, compared with non-OSA controls in the same BMI categories. Individuals with OSA and a normal BMI, however, had the highest risk for gout at 2–5 years after diagnosis, with a 2.02-fold increased risk versus those without OSA.
The question has been raised as to whether treating hypoxia in OSA with continuous positive airway pressure could lower serum uric acid levels and hence reduce the risk for and treat existing gout, say the researchers, noting that randomized controlled trials are now required to provide an answer.
By Catherine Booth
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