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Study finds comorbidity does not affect physical function in patients with OA
Patients with hip or knee osteoarthritis with significant comorbidities reported osteoarthritis affected their activities of daily living, but clinical outcomes showed pain was the significant mediator, rather than osteoarthritis diagnosis, according to recent research.
Sabina Zambon, MD, from the Department of Medicine at the University of Padua in Padua, Italy, and colleagues evaluated the association between comorbidity and pain in 2,942 osteoarthritis (OA) patients in the European Project on Arthritis. Patients were located in Italy, Germany, the Netherlands, Sweden, Spain and the United States and were between 65 years and 85 years old, according to the abstract. The researchers measured outcomes using a 3-meter walking test and the WOMAC physical function subscale.
The comorbidities studied were obesity (≥ 30 kg/m2), anxiety, depression, cognitive impairment, lung disease and cardiovascular disease. Of the patients evaluated, 25% had three or more comorbidities and 22.7% had clinical hip or knee OA.
The researchers found a significant association between hip and knee OA and limitations in physical function; however, there were no significant associations between comorbidities and this limitation, and “pain reduced the effect of OA on self-reported physical function, and it cancelled the effect of OA on the walking test,” according to the abstract. Regarding scoring, patients with anxiety, depression, cardiovascular issues and obesity had the worst WOMAC scores, while cognitive impairment, obesity, peripheral artery disease, depression and stroke were associated with the worst walking times.
“We have demonstrated here that participants believe that more than through pain, OA affects their functional ability while they are performing their daily tasks. This belief was demonstrated by the independent effect of OA on self-reported physical function, even after adjusting for pain,” Zambon and colleagues wrote in their study. “When instead participants were asked to perform the walking test, the actual pain experienced, and not its expectation, affected performance. Pain alone seems then to explain the impairment in walking, mediating the effect of OA.” – by Jeff Craven
Disclosure: Dennison is on the speakers bureau for Eli Lilly.