Gout May Be More Common Among Patients With Ankylosing Spondylitis Than General Population

Gout may be more common in a patient population with ankylosing spondylitis (AS) than in the general population, according to study results published in Rheumatology International.¹

Gout and AS are both prevalent forms of inflammatory arthropathies, although previous studies have suggested that the coexistence of AS and gout in 1 individual is relatively rare.² The objective of this study was to determine whether gout is more common among patients with AS than in the general population, and to describe the association between the 2 conditions.

In this population-based, case-control study, researchers retrieved data from the Clalit Health Services in Israel for adult patients with AS who were aged between 20 and 80 years. Overall, 3763 patients with AS and 19,214 age- and sex-matched healthy controls were included in the study. The majority of patients with AS were men (64.1%) with a mean age of 52.7±14.8 years. Variables, including diagnosis of gout, body mass index (BMI), and smoking history, for both the AS and control groups were included in the study analyses. AS and gout were defined by the presence of at least 1 documented diagnosis by a general physician or rheumatologist, or diagnosis recorded in hospitalization documents. 

Results revealed that gout was more prevalent in the patient group than in the control group (1.94% vs 0.56%, respectively; odds ratio [OR], 3.53; 95% CI, 2.61-4.76; P <.001). Men with AS were more likely to have gout (OR, 3.70; 95% CI, 2.70-5.03; P <.001), and gout was more prominent in patients with AS aged between 40 and 60 years (OR, 5.13; 95% CI, 3.10-8.46; P <.001). Compared with healthy controls, patients with AS were also more likely to be smokers (OR, 4.09; 95% CI, 3.80-4.41; P =.000), and have hypertension (OR, 3.19; 95% CI, 2.95-3.46; P =.000) and hyperlipidemia (OR, 4.16; 95% CI, 3.87-4.48; P =.000). Gout was more prevalent in patients with a BMI lower than 25 (OR, 2.64; 95% CI, 1.13-6.34; P <.001) compared with patients with AS with high BMI. Logistic regression adjusting for possible confounding variables found that AS was independently associated with gout (OR, 1.41; 95% CI, 1.02-1.93; P =.037).

Study limitations included the researchers’ inability to verify diagnoses in the Clalit Health Services  database because of its large size, possible information bias as patients with AS are more likely to be diagnosed with other comorbidities compared with the general population, and the fact that the study design precluded establishment of a temporal relationship between gout and AS.

“[We] suggest that clinicians keep gout in mind as a possible diagnosis when evaluating peripheral and especially lower limb arthritis in patients [with AS], acknowledging that treatment with nonsteroidal anti-inflammatory drugs and other anti-inflammatory medications could alter the classic manifestation of this disease,” the researchers concluded.

Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

References

1. Gonen T, Tiosano S, Comaneshter D, Amital H, Cohen AD, Shovman O. The coexistence of gout in ankylosing spondylitis patients: a case control study [published online October 19, 2019]. Rheumatol Int. doi:10.1007/s00296-019-04462-x

2. Wong DM, Chalmers IM. Coexistent acute gouty arthritis and ankylosing spondylitis. A rare occurrence. J Rheumatol. 1994;21(4):773-774.