Psoriatic Arthritis Strongly Linked With Developing Diabetes Mellitus

The prevalence of diabetes mellitus (DM) is higher in patients with psoriatic arthritis (PsA), with greater PsA activity correlating with a higher risk of developing the disease, according to recent research published in The Journal of Rheumatology.

“Psoriatic arthritis is strongly associated with obesity and its related comorbidities, including DM. In this study, we have found that patients with PsA have 43% higher risk of developing DM compared with the general population,” Lihi Eder, MD, PhD, from the Women’s College Research Institute at Women’s College Hospital and the Department of Medicine at the University of Toronto, told Rheumatology Advisor in an interview.

Dr Eder and colleagues performed a cohort analysis of 1305 patients in a large PsA specialty clinic in Ontario between January 1978 and November 2014 in which they measured the prevalence of DM and calculated the age-standardized prevalence ratio (SPR) of DM compared with the general population. 

To determine the relationship between DM risk factors and PsA disease activity, the researchers measured time-weighted arithmetic mean (AM) tender joint counts, swollen joint counts, dactylitis count, Psoriasis Area Severity Index, and erythrocyte sedimentation rates.

“This risk was especially high in the younger age groups,” Dr Eder told Rheumatology Advisor. “Moreover, we found that having higher levels of disease activity predicted the development of DM in patients with PsA. 

This highlights the potential role of inflammation in development of comorbidities such as diabetes in these patients.”

Specifically, there was a 1.43 SPR for patients with PsA who had DM compared with the general population (P =.002); 73 patients developed DM in the subset of 1065 patients in the time-to-event analysis. 

The researchers noted factors that predicted DM when measuring PsA disease activity included AM erythrocyte sedimentation rate (HR = 1.21; 95% CI, 1.03-1.41; P =.02) and AM tender joint count (HR = 1.53; 95% CI, 1.08-2.18; P =.02).

The researchers said other studies have shown an increased likelihood of patients with rheumatoid arthritis developing DM, but the risk of developing DM appears to be higher in patients with PsA.

“Overall, the cluster of obesity, insulin resistance, and dyslipidemia, collectively termed the ‘metabolic syndrome,’ tends to be more prevalent in patients with PsA than in those with RA,” the researchers wrote in their study. “Therefore, despite similar characteristics of these 2 conditions that involve chronic inflammatory arthritis and systemic inflammation with Th1 response and elevated levels of TNF-α and additional proinflammatory cytokines that could promote insulin resistance, DM risk is higher in patients with PsA.”

Dr Eder and colleagues noted insulin resistance from PsA-specific immune mechanisms, topical corticosteroid preparation, concomitant skin and joint inflammation, and lack of healthy lifestyle could all affect increased DM development in patients with PsA.

Summary & Clinical Applicability

“This finding highlights the need to screen for DM in patients with PsA, especially in those with more active joint disease and elevated inflammatory markers,” the researchers wrote. “The control of inflammation may reduce the risk of developing DM in patients with PsA.”

Study Limitations

• The investigators could not adjust for potential confounding risk factor data (not available) in comparison to the general population of Ontario.
• The definition of DM in the general population was based on self-reported diagnosis, whereas the PsA study group diagnosis of DM was based on physician diagnosis, use of DM medications, or elevated blood glucose levels.
• The generalizability of results may be limited because patients with PsA in this study were seen at a specialty clinic and, therefore, may represent a more severely affected group of patients.

Disclosures

Dr Eder has received support from the Krembil Foundation and a fellowship award from the Canadian Institutes of Health Research.

Reference

Eder L, Chandran V, Cook R, Gladman DD. The risk of developing diabetes mellitus in patients with psoriatic arthritis: a cohort study [published online February 1, 2017]. J Rheumatol. doi:10.3899/jrheum.160861

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