Sensitivity analysis
SE, chronic neck pain, NDI, NRS
SENSITIVITY
The results of the sensitivity analysis are presented in Table 
Results of uncertainty analysisFor the base case analysis, QALY was calculated with EQ-5D in societal perspectives. The distribution of cost and QALY was calculated by non-parametric bootstrap. The incremental net benefit (INB) was calculated using the 1xWTP threshold ($26,375) and 1xGDP per capita ($31,838)In the main analysis, patients assigned to each group were followed-up up to 12 weeks, and missing values were imputed with multiple imputation. The costs from the healthcare system perspective include the costs of formal and informal healthcare involved in chronic neck pain treatment and the transportation and time costs. For the costs in the societal perspective, productivity costs from chronic neck pain are included.Sensitivity analysis. 1 was a per-protocol analysis, which included patients who received at least six treatment sessions (47 in the pharmacopuncture group and 45 in the physical therapy group). Sensitivity analysis 2. Assuming that only employed patients suffered income loss due to time and productivity losses. Sensitivity analysis 3. We applied $26 by multiplying 1.5 with the pharmacopuncture cost in the base case analysis. Sensitivity analysis 4. We applied $35 by multiplying 2 with the pharmacopuncture cost in the base-case analysis. Sensitivity analysis 5. Cost effectiveness analysis based on NRS and NDI.
First, a cost-effectiveness analysis was performed on patients who had received at least six treatment sessions. The difference in costs was $1,149 from a societal perspective and $36 from a healthcare perspective. On the CE plane, CE pairs showed the highest distribution of 81.3% in the SE quadrant; thus, the probability of pharmacopuncture being more cost-effective from a societal perspective was 100% based on QALY.