Patients with obstructive sleep apnoea have a higher risk of developing gout, even beyond the first years after being diagnosed with the sleep disorder, according to researchers.
They noted that apnoea was associated with a range of serious comorbidities and it had previously been shown that people with it had a higher risk of developing gout in the first year after diagnosis.
“People with sleep apnoea are at an increased risk of gout in both the short and long term”
To investigate whether they may also be more likely to develop gout over a longer term, the team examined information on 15,879 patients with apnoea and 63,296 without over around six years.
During follow-up, the researchers from Keele University found 4.9% of obstructive sleep apnoea and 2.6% of non-apnoea patients developed gout.
Incidence rates per 1,000 person-years – a person-year represents the number of years of follow-up multiplied by the number of people in the analysis – were 7.83 and 4.03 among those with and without apnoea, respectively, giving a 42% increased risk among apnoea patients.
An elevated risk of developing gout was observed throughout follow-up for obstructive sleep apnoea patients, but it was highest one to two years after diagnosis of obstructive sleep apnoea.
This finding was seen in patients with normal body mass index as well as those who were overweight or obese, noted the researchers. However, the risk was greater in those with normal weight.
Study author Dr Edward Roddy said: “People with sleep apnoea are at an increased risk of gout in both the short and long term.
“Since this risk was highest in people with normal body mass index, doctors and other health professionals should consider the possibility of gout in patents with sleep apnoea regardless of body mass index,” he said.
The researchers noted that it was thought that intermittent oxygen deficiency due to obstructive sleep apnoea leads to over-production of uric acid, which causes gout.
Fellow study author Dr Milica Blagojevic-Bucknall said: “Sleep apnoea is commonly treated with continuous positive airways pressure – or CPAP – therapy.
“Since CPAP treatment corrects low oxygen levels it might also be expected to reduce uric acid levels, which could possibly reduce the risk of developing gout or treat existing gout,” she said.
“However, further research is needed to investigate the effect of treatment with CPAP in people with gout,” said Dr Blagojevic-Bucknall.
The Keele University findings are published in the American College of Rheumatology’s journal Arthritis and Rheumatology.