medwireNews: Study findings confirm suspicions that patients with diabetes have an increased risk for adhesive capsulitis of the shoulder (ACS).
Using insurance claims data for 96% of the Taiwanese population between 2000 and 2003, the researchers compared the incidence of ACS in 78,827 patients with at least ambulatory visits for diabetes and 236,481 age- and gender-matched individuals without diabetes.
After a median of 31.87 months of follow-up, 1.20% of diabetes patients and 0.95% of controls were diagnosed with ACS, at rates of 4.92 and 3.67 cases per 1000 person-years, respectively, say Shin-Liang Pan (National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei) and co-workers.
Patients with diabetes were a significant 1.32 times more likely to develop ACS than individuals without diabetes, after adjusting for age, gender, and dyslipidemia, the team reports in Arthritis Care and Research.
The increased risk in diabetes patients did not significantly alter when the researchers strictly defined ACS to be diagnosis by two doctors, one of which should be a rheumatologist, orthopedist, or physiatrist (hazard ratio [HR]=1.32).
Indeed, the risk for ACS remained significant for patients with diabetes (HR=1.25) even after accounting for confounding through medical surveillance, due to the increased number of doctor visits per month by diabetes patients compared with controls (2.0 vs 1.4).
Pan et al hypothesize that chronic inflammation associated with diabetes may lead to joint synovitis and capsular fibrosis, resulting in ACS. They cite research demonstrating elevated vascular endothelia growth factor and pro-inflammatory cytokines, such as interleukin 1, in the capsule and synovial fluid of ACS patients compared with controls.
The team concludes: "Further studies are required to investigate the underlying pathophysiological mechanism for this positive association between [diabetes mellitus] and ACS."
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