Neck-Specific Exercises With Internet Support Versus Standard Neck-Specific Exercise for the Treatment of Chronic Whiplash-Associated Disorders: Cost-Effectiveness Analysis

BACKGROUND: There is currently scarce information about the cost-effectiveness of interventions for individuals with chronic whiplash-associated disorders (WAD) or of internet-based exercise programs for neck pain, including WAD. OBJECTIVE: This study aimed to investigate the cost-effectiveness of a 3-month neck-specific exercise program with internet support in combination with 4 physiotherapy visits (neck-specific exercise with internet support [NSEIT]) compared with the same exercises performed twice a week (24 times) at a physiotherapy clinic (neck-specific exercise [NSE]) for individuals with chronic WAD. METHODS: This was a prospective, multicenter, randomized controlled trial of the cost-effectiveness of the interventions among 140 individuals with chronic moderate to severe WAD with 3- and 15-month follow-up. The main outcome was the incremental cost-effectiveness ratio (ICER). RESULTS: At the 15-month follow-up, the total costs calculated for NSEIT and NSE were SEK 12,882 (95% CI 17,406.30-8358.42) and SEK 40,087 (95% CI 51,764.32-28,410.96), respectively (SEK 1=US $0.10 as of October 6, 2026). The health-related quality of life (HRQoL) score at 15 months was 0.662 (95% CI 0.73-0.59) and 0.711 (95% CI 0.77-0.65) for NSEIT and NSE, respectively. The ICER for HRQoL was SEK 555,209.80 per point when the NSEIT group was compared with NSE. The internet-based intervention was less costly and less effective than NSE at the 15-month follow-up. The cost-effectiveness acceptability curve showed that at a willingness to pay threshold of SEK 500,000 per point, there was a moderate probability (0.57) of the intervention being cost-effective with a loss of HRQoL. One-way sensitivity analysis showed that the health care costs of individuals receiving NSE and NSEIT affected the ICER. CONCLUSIONS: NSEIT intervention-an eHealth intervention for chronic WAD-was less costly and less effective compared with NSE. Health care costs associated with both interventions affected the ICER; therefore, patients' overall well-being should also be considered when treating chronic WAD. Even though the cost effectiveness acceptability curve showed that the cost savings from NSEIT outweighed the lost health outcomes, the reliability of the findings was limited by the exclusion of presenteeism costs, patients' self-reported health care use, and the small difference in health outcomes. TRIAL REGISTRATION: ClinicalTrials.gov NCT03022812; https://clinicaltrials.gov/study/NCT03022812.