Effectiveness and cost-effectiveness of a health coaching intervention to improve the lifestyle of patients with knee osteoarthritis: cluster randomized clinical trial

Background: The prevalence of osteoarthritis and knee osteoarthritis in the Spanish population is estimated at 17% and 10.2%, respectively. The clinical guidelines concur that the first line treatment for knee osteoarthritis should be non-pharmacological and include weight loss, physical activity and self-management of pain. Health Coaching has been defined as an intervention that facilitates the achievement of health improvement goals, the reduction of unhealthy lifestyles, the improvement of self-management for chronic conditions and quality of life enhancement. The aim of this study is to analyze the effectiveness, cost-effectiveness and cost-utility of a health coaching intervention on quality of life, pain, overweight and physical activity in patients from 18 primary care centres of Barcelona with knee osteoarthritis. Methods/Design: Methodology from the Medical Research Council on developing complex interventions. Phase 1: Intervention modelling and operationalization through a qualitative, socioconstructivist study using theoretical sampling with 10 in-depth interviews to patients with knee osteoarthritis and 4 discussion groups of 8-12 primary care professionals, evaluated using a sociological discourse analysis. Phase 2: Effectiveness, cost-effectiveness and cost-utility study with a community-based randomized clinical trial. Participants: 360 patients with knee osteoarthritis ( 180 in each group). Randomization unit: Primary Care Centre. Intervention Group: will receive standard care plus 20-hour health coaching and follow-up sessions. Control Group: will receive standard care. Main Outcome Variable: quality of life as measured by the WOMAC index. Data Analyses: will include standardized response mean and multilevel analysis of repeated measures. Economic analysis: based on cost-effectiveness and cost-utility measures. Phase 3: Evaluation of the intervention programme with a qualitative study. Methodology as in Phase 1. Discussion: If the analyses show the cost-effectiveness and cost-utility of the intervention the results can be incorporated into the clinical guidelines for the management of knee osteoarthritis in primary care.