medwireNews: Study findings suggest that men with gout, particularly those with poor serum urate control, may have an elevated risk for lower extremity amputation (LEA).
Ted Mikuls (University of Nebraska Medical Center, Omaha, USA) and co-researchers drew on data from the US Department of Veterans Affairs Health System to compare LEA rates for 2000–2015 in 556,521 people with gout and 5,368,397 individuals without. Almost all (99%) of the cohort were men, with an average age of 67 years.
As reported in JAMA Network Open, 4970 LEAs were performed during 3.4 million person–years of follow-up in the gout group, compared with 24,583 procedures during 32.1 million person–years in the control group, giving incidence rates of 1.46 versus 0.77 per 1000 person–years.
Multivariable analysis demonstrated that people with gout had a significant 20% higher risk for LEA than those without after adjustment for factors including age, sex, race, BMI, and comorbidities associated with amputation risk such as diabetes, chronic kidney disease, and peripheral vascular disease.
These findings remained consistent when the different types of LEA were analyzed separately, with significant risk increases associated with gout ranging from 11% for transmetatarsal LEAs, 22% for above-knee LEAs, and 59% for below-knee amputations.
In the gout group, Mikuls et al found that serum urate levels, but not urate-lowering therapy (ULT), were associated with elevated ULT risk. Specifically, having suboptimal urate levels (average >7 mg/dL in each year of follow-up) was associated with a significant 26% increased LEA risk for people with suboptimal ULT (no receipt of allopurinol, febuxostat, or probenecid for at least 90 days per year), and a 37% increased risk for those with adequate or indeterminate ULT.
This association between serum urate control and LEA risk points to “the possibility that lower extremity amputation may be preventable in some patients,” say the researchers.
Taken together, the study findings have “prognostic implications for patients with gout,” as 5-year mortality rates following LEA are “approaching 70% in patients with diabetes,” with “only slightly lower rates among those without diabetes,” remark the authors.
They also note that extrapolation of the results to the US general population including 9.2 million adults with gout suggested a cumulative LEA incidence of approximately 2% during 15 years of follow-up, indicating “that as many as 184 000 patients with gout are at risk of undergoing LEA during the coming years in the US alone,” say Mikuls and team.
They conclude: “Further investigation is needed to understand the indications for LEA procedures conducted in gout in addition to identifying potential means of prevention as a way of ultimately improving long-term outcomes in this population.”
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JAMA Netw Open 2022; 5: e2142347