Parallel Studies Identify, Compare Risk Factors for Inflammatory Conditions

Investigators in the US and Iceland who conducted 4 parallel case-control studies to identify and compare factors that may contribute to the risk of developing psoriatic arthritis (PsA), psoriasis (PsO), rheumatoid arthritis (RA), and ankylosing spondylitis (AS) found that smoking was a shared risk factor among all the conditions and all were inversely associated with statin use.

Using the Health Improvement Network (THIN), a large European database of anonymized and nonextrapolated Electronic Health Records, the researchers investigated data for the period 1994 through 2015. Patients with PsA, PsO, RA, or AS were matched to controls based on age, sex, year, and practice. The team built multivariable logistic regression models for each condition and applied automated stepwise regression to test potential risk factors.

“Patients with incident PsA (n=7594), PsO (n=111,375), RA (n=28,341), and AS (n=3253) were identified and matched to 75,930, 1,113,345, 283,226, and 32,530 controls, respectively,” the authors wrote. “Median diagnosis age was 48 (IQR 38–59), 43 (IQR 28–60), 60 (IQR 48–71), and 41 (IQR 32–54) years, respectively.”

Multivariable models identified shared and differing risk factors across all 4 diseases, researchers reported. “PsA was associated with obesity, pharyngitis, and skin infections; PsA and PsO were associated with obesity and moderate alcohol intake; PsA and AS were associated with uveitis; and PsA and RA were associated with preceding gout. Both RA and AS were associated with current smoking, former moderate drinking, anemia, osteoporosis, and inflammatory bowel disease,” the investigators found.

—Rebecca Mashaw

Reference:
Meer E, Thrastardottir T, Wang X, et al. Risk factors for diagnosis of psoriatic arthritis, psoriasis, rheumatoid arthritis, and ankylosing spondylitis: A set of parallel case-control studies. J Rheumatol. 2022;49(1):53-59. DOI: https://doi.org/10.3899/jrheum.210006