P451 COST EFFECTIVENESS OF RIFAXIMIN-a IN THE REDUCTION OF RECURRENCE OF OVERT HEPATIC ENCEPHALOPATHY

Abstract

Introduction: Hepatic encephalopathy (HE) is associated with high morbidity and mortality. Rifaximin-α is effective in reducing the recurrence of episodes of overt HE. The aim was to characterise the cost effectiveness of rifaximin-α versus standard care (lactulose). Methods: This economic evaluation used a Markov state transition model. The outcome was the incremental cost effectiveness ratio (ICER), derived from estimates of the cost/quality adjusted life years. The payer perspective was that of UK National Health Service. Outcome data were from two trials of rifaximin-α. Population outcome data were from a complementary study of patients with liver cirrhosis treated within the NHS. Cost data (GBP£2012) were derived from published sources. Health-related utility was estimated indirectly from disease-specific trial QoL data. The time horizon was five years. Costs and benefits were discounted at 3.5%. Extensive sensitivity analysis was carried out. Results: The average cost of the included elements of care was £15,476 in the rifaximin-α arm and £4,486 in the lactulose arm, a difference of £10,990. The corresponding values for benefit was 2.36 QALYs, and 1.83 QALYs per person, respectively; a difference of 0.53 units. This translated into a base-case ICER of £20,852/QALY. Key parameters that impacted the ICER included the event-free survival pattern, ranging from an ICER of £13,919 using an exponential model, to £21,425/QALY using a log-logistic model. Evaluation to 10 years resulted in an ICER of £19,122/QALY. Conclusion: Rifaximin-α in patients with liver cirrhosis was cost effective compared to standard care, reducing episodes of overt hepatic encephalopathy.