PARIS – Patients with knee osteoarthritis are significantly more likely to experience a flare if they report a higher negative mood in the previous 10 days.
Passive coping strategies such as "I restrict my social activities" or "I focus on the location and intensity of pain" were also significantly associated with an increased risk of flares, while more active coping strategies were protective in a Web-based, case-crossover study.
"We really need to elaborate on this, replicate it, and elucidate this connection because psychosocial factors of mood and pain coping are modifiable and ultimately may improve our patients experience of this disease, osteoarthritis," Dr. David J. Hunter said at the World Congress on Osteoarthritis.
The investigators recruited 298 patients with symptomatic knee osteoarthritis (OA) and asked them to log on to the study website if they experienced a knee pain exacerbation over 3 months of follow-up.
Daily mood (negative/positive) in the previous 10 days was assessed using the Profile of Mood States (POMS) questionnaire. The Pain Coping Inventory (PCI) was used to assess daily pain coping in the previous 30 days.
Pain exacerbation during follow-up was defined as a 2-unit increase in the patient’s visual analog knee pain score (10-point scale) from his or her mildest pain score reported at the baseline visit, said Dr. Hunter, the Florance and Cope Chair of Rheumatology, Northern Clinical School, University of Sydney, Australia.
Most of the patients were female (61%) and white (92%), and their average body mass index was 29.4 kg/m2. Their average baseline Knee injury and Osteoarthritis Outcome Score (KOOS) symptoms subscale score was 44.5 and KOOS pain subscale score 55.6.
The average POMS positive mood score was 33.9 and average negative mood (for example, distressed, irritable, nervous) score 16.5, both on a 50-point scale. The average PCI passive coping score was 8.1 on a 24-point scale, and average PCI active coping score 12.2 on a 20-point scale.
In conditional logistic regression analyses, increasing negative affect scores were significantly associated with having a pain exacerbation (P less than .001) such that patients with a score of 13-17 were nearly three times more likely to experience a flare (odds ratio, 2.77) and those with a score of 18 or more were 6.5 times more likely to do so (OR, 6.5), Dr. Hunter said.
Patients with higher PCI passive coping scores were also significantly more likely to have a pain exacerbation (OR, 1.26; P = .01), while those with more active coping strategies such as "I stay busy or active," or "I clear my mind of bothersome thoughts" were less likely to have a pain flare (OR, 0.81; P = .03).
During a discussion of the results, Dr. Hunter said they have yet to look at trajectories to see whether patients returned to their prior pain level.
Session comoderator Aileen Davis, Ph.D., senior scientist with the Toronto Western Research Institute, said the general literature recognizes there is a psychosocial component to OA pain, but that this is the first study to make the direct link with OA pain flares.
If the results can be replicated, "It means there’s a lot more we can do in terms of coping strategies and in recognizing this a lot more often," she said in an interview at the meeting, sponsored by the Osteoarthritis Research Society International.
Since many OA patients are cared for by primary care physicians, Dr. Davis suggested they may want to have a psychosocial profile of their OA patients and push management strategies or referrals to psychologists or social workers skilled in coping strategies to patients who are "fluctuators," so they can "proactively change how they’re doing things."
Dr. Hunter reported support from the Australian National Health and Medical Research Council.