Background
Strong association was documented between human leukocyte antigen (HLA)-B*15:02 and carbamazepine-induced severe cutaneous adverse reactions (SCARs) in Asians. Beyond Asia, the HLA testing is potentially valuable in many countries with increasingly diverse communities of Asian ancestry, to facilitate an early recognition of patient susceptibility to SCARs.
Objective
To determine the cost-effectiveness of universal HLA-B*15:02 screening in preventing carbamazepine-induced Stevens-Johnson syndrome/ toxic epidermal necrolysis in an ethnically-diverse Malaysian population.
Methods
A hybrid model of a decision tree and Markov model was developed to evaluate three strategies for treating newly-diagnosed epilepsy among adults - (i) carbamazepine initiation without HLA-B*15:02 screening (current practice); (ii) universal HLA-B*15:02 screening prior to carbamazepine initiation; and (iii) alternative treatment [sodium valproate (VPA)] prescribing without HLA-B*15:02 screening. From a societal perspective, base-case analysis and sensitivity analyses were performed over lifetime time horizon. Incremental cost-effectiveness ratios were calculated.
Results
In the base-case analysis, both universal HLA-B*15:02 screening and VPA prescribing were dominated by current practice. Compared to current practice, universal HLA-B*15:02 screening resulted in 0.0255 quality-adjusted life years (QALYs) loss at an additional cost of USD707, while VPA prescribing resulted in 0.2622 QALYs loss at an additional cost of USD4,127, due to estimated differences in antiepileptic treatment efficacy.
Conclusions
This study suggests that universal HLA-B*15:02 screening is unlikely to be a cost-effective intervention in Malaysia compared to current practice. However, with the emergence of an ethnically-diverse population in many other countries, this may render HLA-B*15:02 screening a potentially viable intervention when an increasing proportion of the population is at risk and an equally effective yet safer antiepileptic drug is available.