Obesity may attenuate efficacy of exercise-based motivational interviewing
Obesity appears to have a negative effect on the potential of exercise-based motivational interviewing (MI) to improve symptom severity and pain in patients with fibromyalgia (FM), according to study.
The current study is a secondary analysis of a trial that randomized 198 FM patients (age range, 18 to 65 years) to treatment with either MI or attention control (AC). Patients were divided according to their obesity status, obese (54 percent; body mass index [BMI], ≥30 kg/m2) and nonobese (46 percent; BMI, <30 kg/m2).
Both MI and AC groups received two supervised exercise sessions and a personalized exercise prescription that included the initial exercise frequency (2 to 3 days/week), intensity (40 to 50 percent of heart rate reserve [HRR]), duration (10 to 12 minute/session) and progression over the succeeding 36 weeks. After completing both exercise sessions, patients in the MI group received either six counselling sessions aimed at resolving an individual’s ambivalence about and improving adherence to the exercise intervention. On the other hand, patients in the AC group received six sessions of FM-related health education over 12 weeks. Assessments were conducted at week 12 (immediate post-intervention), week 24 (3-month follow-up) and week 36 (6-month follow-up).
The primary outcome was global FM symptom severity, as assessed using Fibromyalgia Impact Questionnaire (FIQ). Secondary outcome measures included pain intensity (Brief Pain Inventory, BPI), 6-minute walk test and self-reported physical activity (Community Health Activities Model Program for Seniors). Mixed linear models were used to evaluate the interaction between treatment arms and obesity status.
Results showed a significant interaction between treatment arms and obesity status with regard to the global FM symptom severity (p=0.02). Compared with AC, MI produced a greater improvement in FIQ among nonobese patients but less improvement among obese patients. The interaction was also observed for BPI pain intensity (p=0.01) but not for the walk test and self-reported physical activity.
A common chronic pain disorder, FM is characterized by symptoms including fatigue, anxiety, cognitive impairment and reduced physical functioning. Patients with worsening FM exhibit a progressive decline in physical activity, which possibly contributes to excessive weight gain and worsening pain symptoms. As a treatment intervention, MI is an attractive approach for improving treatment adherence in chronic pain conditions, having been shown to be effective at modifying several health risk behaviours (ie, physical inactivity). [Clin J Pain 2010;26:284–90; Phys Ther 2006;86:1479–88; Clin Rheumatol 2008;27:1543–7; J Pain 2010;11:1329–37]
Findings of the present analysis indicate that obesity may potentially hamper the ability of MI to improve physical activity and clinical outcomes in individuals with FM. Given this, researchers noted that exercise-based MI might be more effective if initiated after achievement of weight loss.
Although additional studies are needed to further examine the clinical effectiveness of behavioural interventions that combine physical activity and weight management counselling on clinical outcomes in FM, the current data should aid “clinician decision-making regarding the role of exercise-based MI in the treatment algorithm for patients with FM,” they added.