There was a significant between-group difference in effectiveness at 52 weeks: 79% (53 out of 67) of GP plus physical therapy care patients reported improved GPE compared to 56% of those with GP care only (relative risk 1.4, 95% CI 1.1-1.8). Mean utility values were 0.39 for GP plus physical therapy and 0.41 for GP care only at baseline; there was a statistically significant utility difference in favour of GP care only at the six-week time point.
Total cumulative (direct and indirect) mean costs (with standard deviation) were: €1,408.9 (1,616.8) for GP plus physical therapy care and €1249.8 (standard deviation 1,772.8) for GP care alone (p<0.0) at three weeks; €2,337.8 (2,616.9) for GP plus physical therapy care and €1,871.9 (2,846.5) for GP care alone at six weeks; €3,539.2 (4,320.9) for GP plus physical therapy care and €2,832.9 (5,179.8) for GP care alone (p<0.0) at 12 weeks; and €6,248.9 (9,602.5) for GP plus physical therapy care and €4,804.9 (9,803.2) for GP care alone (p<0.0) at 52 weeks.
Using direct costs only, the ICER was €837 per improved patient gained (95% CI -732 to 3,186). Using total costs, the ICER rose to €6,224 per improved patient gained (95% CI -10,419 to 27,551).
Using direct costs only, the intervention had a probability of being cost-effective compared with the control group of 35% at a willingness-to-pay threshold of €600 per patient improved and 69% at a threshold of €1,200. Using total costs a threshold of €4,000 was required for a cost-effectiveness probability of 37% and a threshold of €12,000 was required for a probability of 68%.