Sex, ethnicity, comorbidity tied to poor gout control prevalence in SG

In Singapore, poorly controlled gout appears to be common among men, Malays, and individuals with congestive cardiac failure, as reported in a study.

Data from 7,970 patients (mean age 61.7 years, 83.6 percent men, 76.8 percent Chinese) and 24,624 clinic visits showed that poorly controlled gout was prevalent in 2,244 (28.2 percent). More than half of those with poorly controlled gout (n=1,205, 53.6 percent) and about two-thirds of patients with well-controlled gout (n=3,589, 62.7 percent) were not prescribed allopurinol. [Front Med 2023;10:1253839]

Younger people, men, those of Malay ethnicity, and those with higher serum uric acid (SUA) were more likely to have poorly controlled gout. The same was true for individuals prescribed allopurinol, nonsteroidal anti-inflammatory drugs (NSAIDs), and corticosteroids, as well as those with comorbidities such as diabetes, hyperlipidaemia, and hypertension.

In multivariable logistic regression models, poor gout control was associated with male gender (adjusted odds ratio [aOR], 1.66; p<0.001), Malay ethnicity (aOR, 1.27; p=0.007), congestive heart failure (aOR, 1.64; p=0.037), as well as use of allopurinol (aOR, 1.52; p<0.001), NSAIDs (aOR, 2.76; p<0.001), and corticosteroids (aOR, 2.83; p<0.001).

Low allopurinol prescription

Poorly controlled gout was characterized as two or more gout attacks within 12 months, with attacks defined as a clinic visit with a diagnosis of “gout” and colchicine not prescribed as prophylaxis or standby.

“Patients on allopurinol were one and a half times more likely to have poorly controlled gout. The definition of poorly controlled gout adopted can explain this finding as patients suffering two or more flares a year should be started on allopurinol,” according to the investigators.

“Concerningly, allopurinol was only prescribed in approximately half of patients with poorly controlled gout, placing these patients at increased morbidity and mortality risks,” they added. [Circulation 2007;116:894-900]

The investigators pointed out that this low allopurinol prescription may be attributed to therapeutic inertia among physicians. For the most part, physicians are concerned about the risk of allopurinol-induced severe cutaneous adverse reactions (SCAR). It also doesn’t help that the risk of SCAR is further heightened in the local population where the majority ethnic group is Chinese, owing to HLA-B*5801 allele. [Ann Rheum Dis 2012;71:1490-1495; Ann Rheum Dis 2007;66:1685-1686; Clin Pharmacol Ther 2016;99:36-37]

Although available, testing for the allele can be expensive, with a local study showing that HLA-B*5801-guided urate-lowering therapy (ULT) selection was not cost-effective based on a threshold of USD 50,000 per quality-adjusted life year. Consequently, health authorities released an advisory that recommends against routine HLA-B*1501 testing prior to initiating a patient on allopurinol. HLA-B*5801 testing may only be considered for individuals with an elevated risk for SCAR, such as those with renal impairment or advanced age. [Pharmacogenomics 2015;16:1781-1793; https://www.hsa.gov.sg/announcements/safety-alert/allopurinol-induced-severe-cutaneous-adverse-reactions-and-the-role-of-hla-b-5801-genotyping-a-reminder]

“Nonetheless, the worry about iatrogenic SCAR remains, probably due to the severity of its consequences, even though only approximately three out of a thousand individuals are at risk of developing SCAR,” the investigators noted.

Ultimately, the findings of the present study highlight a need to overcome therapeutic inertia among primary care physicians. “Primary care physicians need to optimize ULT for their patients to regain and sustain gout control,” the investigators said.