WASHINGTON — High temperature and humidity appear to increase the risk of recurrent gout attacks independently of other known risk factors, Yuqing Q. Zhang, D.Sc., reported at the annual meeting of the American College of Rheumatology.
“Although the pathophysiology of gout is well understood and efficacious clinical therapies are available, many patients with gout still suffer from recurrent gout attacks” that are brought on by certain risk factors, said Dr. Zhang of Boston University.
Decreases in intravascular volume as a result of perspiration in hot and humid weather can result in high serum uric acid levels because of a reduction in uric acid excretion, Dr. Zhang said.
Only a handful of studies have examined the relationship between risk factors for dehydration and the risk of gout attack recurrence.
Dr. Zhang and his colleagues enrolled 197 patients with a median 5-year history of gout through an online advertisement.
The patients answered a “hazard period” questionnaire on a Web site that asked about risk factors for gout attacks during the 2-day period prior to their report of an attack.
They also filled out a control period questionnaire every 3 months for 1 year to provide data about time intervals during which gout attacks did not occur.
The questionnaires asked about use of dehydrating medication (such as diuretics), alcohol use, food intake (especially foods rich in purine or with little purine), and details of gout attacks when they occurred.
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As temperature during the 2 days prior to a gout attack increased from the lowest quintile (0–53°F) to the highest quintile (87–105°F), the relative risk of a gout attack doubled.
The dose-response relationship between temperature and recurrent gout attacks seemed to suggest a threshold effect such that when the temperature reached 85°F, the risk of recurrent gout attacks increased dramatically, according to Dr. Zhang.
The relationship between the level of humidity during the 2 days prior to a gout attack and the risk of recurrent attacks followed the pattern for temperature very closely.
High humidity appeared to be the strongest predictor for recurrent gout attacks, but very cold and dry weather also slightly increased the risk of recurrent attacks.
The findings remained significant after controlling for medication use (especially diuretics), alcohol consumption, and purine-rich food intake.
Recurrent gout attacks were not associated with barometric pressure or precipitation.
“In hot and humid weather, subjects with gout may need to increase fluid intake to counteract volume depletion and to prevent a recurrent gout attack,” Dr. Zhang concluded.