Anemia identified as risk factor for gout
Anemia is a novel risk factor for gout, doubling the risk before adjusting for serum urate levels and kidney function, according to population-based study results.
Researchers investigated 10,791 people (mean age at cohort entry, 54 years; 43% men; 21% African-American) recruited between 1987 and 1989 as part of the Artherosclerosis Risk in the Communities study, with follow-up of 9 years. They defined anemia as baseline hemoglobin of less than or equal to 13.5 g/dL for men and less than or equal to 12 g/dL for women. HR and CI of incident gout by baseline anemia, adjusted for confounders (sex, race, estimated glomerular filtration rate, body mass index and alcohol intake), clinical factors (coronary heart disease, congestive heart failure, diabetes, hypertension and diuretic use) and serum urate level were determined by Cox proportional hazards model.
At baseline 10% of participants (66% women) had anemia, and there were 271 cases of incident gout (39% women, 38% African-American). During follow-up, patients with anemia had twice the risk for developing gout (HR=2.01; 95% CI, 1.46-2.76). With adjustment for confounders and clinical risk factors, anemia remained associated with gout (HR=1.73; 95% CI, 1.24-2.41), as well as when adjusted for serum urate level (HR=1.83; 95% CI, 1.30-2.57). There were no significant risk measures by race or kidney function. Women were more likely (HR=2.38; 95% CI, 1.47-3.84) than men (HR=1.43; 95% CI, 0.88-2.30) to develop gout if they were anemic.
The study was limited because participants had to wait until final follow-up to self-report gout, with incidence of gout based on reported age at onset, the researchers said.
“Our … study is the first to identify anemia as a novel risk factor in middle-aged men and women of both races,” the researchers concluded. “Future studies should … further elucidate the biological pathways of anemia and gout. In particular, the role of gout in women should be explored in greater detail, especially with a prospective ascertainment of fibroids.”