Cost-effectiveness modeling for neuropathic pain treatments: investigating the relative importance of parameters using an open-source model.

AIMS: The study objective was to develop an open-source replicate of a cost-effectiveness model developed by National Institute for Health and Care (NICE), in order to explore uncertainties in health economic modeling of novel pharmacological neuropathic pain treatments.

MATERIALS AND METHODS: The NICE model, consisting of a decision tree with branches for discrete levels of pain relief and adverse event (AE) severities, was replicated using R, and used to compare a hypothetical neuropathic pain drug to pregabalin. Model parameters were sourced from NICE's clinical guidelines and associated with probability distributions to account for underlying uncertainty. A simulation-based scenario analysis was conducted to assess how uncertainty in efficacy and AEs affected the net monetary benefit (NMB) for the hypothetical treatment at a cost-effectiveness threshold of £20,000 per QALY.

RESULTS: Relative to pregabalin, an increase in efficacy was associated with greater NMB than an improvement in tolerability. A greater NMB was observed when efficacy was marginally higher than that of pregabalin, while maintaining the same level of AEs than when efficacy was equivalent to pregabalin, but with a more substantial reduction in AEs. In the latter scenario, the NMB was only positive at a low cost-effectiveness threshold.

LIMITATIONS: The replicate model shares the limitations described in the NICE guidelines. There is a lack of support in scientific literature for the assumption that increased efficacy is associated with a greater reduction in tolerability. The replicate model also included a single comparator, unlike the NICE model.

CONCLUSIONS: Pain relief is a stronger driver of NMB than tolerability, at a cost-effectiveness threshold of £20,000 per QALY. Health technology assessment decisions which are influenced by NICE's model may reward efficacy gains, even if they are associated with more severe AEs. This contrasts with recommendations from clinical guidelines for neuropathic pain, which place more equal weighting on improvements in efficacy and tolerability as value drivers.