Cost-Utility and Cost-Effectiveness Analysis of Spinal Cord Stimulation for Chronic Refractory Pain in the Context of Developing Country

Abstract

BACKGROUND: Spinal cord stimulation (SCS) is an effective treatment for chronic refractory pain. The evidence of pain reduction, improvement of function, quality of life, and cost-effectiveness are strong in developed countries. Nevertheless, there is still a lack of economic studies of SCS in the context of low- and middle-income countries. OBJECTIVES: To evaluate the cost-effectiveness and cost-utility of additional SCS to conventional management (CMM) in patients with chronic refractory pain in Thailand. STUDY DESIGN: Prospective observational study. SETTING: The pain clinic at Siriraj Hospital, a tertiary care center in Thailand. METHODS: This study recruited patients undergoing SCS implants due to refractory pain to CMM from varieties of conditions and followed up to 36 months. The clinical outcomes, quality of life, and costs of treatment were collected before and after SCS implantation. A decision tree and Markov model were developed to estimate the total lifetime costs and health benefits of SCS using a societal perspective. The results were presented as an incremental cost-utility ratio (ICUR) in 2021 Thai Baht (THB) per quality-adjusted life year (QALY) gained and an incremental cost-effective ratio (ICER) in 2021 THB per numeric rating pain score (NRS) reduction. RESULTS: Twenty-nine patients who underwent SCS implantation reported pain intensity and increased utility at every point in time. Compared to pre-implantation, the QALY gained in both rechargeable and non-rechargeable SCS was 2.13 QALYs. The economic analysis showed the ICUR in the rechargeable and non-rechargeable SCS + CMM group was 660,106.96, and 620,120.59 THB/QALY gained, respectively, which was higher than Thais’ willingness-to-pay (WTP) threshold at 160,000 THB/QALY gained. Pain score reduction was 2.49/10 at the 3-year point, and the ICER was 496,932.08 and 337,341.77 THB/NRS reduction for rechargeable and non-rechargeable SCS, respectively. LIMITATIONS: As this is a single-center prospective cohort study, the results might be subject to selection bias and may not truly represent all patients from a developing country. The cost-effectiveness results should also be carefully interpreted for generalizability. CONCLUSION: Spinal cord stimulation is effective in pain control and improves the quality of life for patients with chronic refractory pain. However, the ICUR of SCS is above the WTP, leading to the interpretation that SCS is still not a cost-effective treatment in the current context in Thailand. KEY WORDS: Spinal cord stimulation, effectiveness, quality-adjusted life year, incremental cost-utility ratios, cost-utility analysis, cost-effectiveness analysis, willingness to pay, developing country