LAUSR

AIMS To assess healthcare costs and hospitalization rates associated with rifaximin therapy versus lactulose alone among patients at risk for hepatic encephalopathy (HE). METHODS AND MATERIALS IBM Marketscan® Commercial and Optum's de-identified Clinformatics® Data Mart databases were used separately to identify commercially insured HE patients treated with rifaximin or lactulose alone, using an algorithm developed with clinical experts. HE-related hospitalizations were defined based on an algorithm using diagnosis codes and diagnosis-related group codes. HE-related/all-cause hospital admissions/days and healthcare costs were compared between rifaximin and lactulose episodes using incidence rate ratios and adjusted cost differences. RESULTS In Marketscan, there were 13,515 [Optum: 5,217] rifaximin episodes and 9,946 [4,897] lactulose alone episodes included. Yearly rates of HE-related hospital admissions decreased by 33% [34%] when treated with rifaximin versus lactulose alone, and rates of HE-related hospital days similarly decreased by 43% [57%]. Yearly rates of all-cause hospital admissions decreased by 27% [27%]; rates of all-cause hospital days decreased by 33% [37%] during rifaximin episodes versus lactulose alone. This translated to $2,417 [$2,301] and $173 [$397] lower total mean medical costs and HE-related hospital costs per-patient-per-month, respectively (p < 0.05). Despite increased pharmacy costs associated with rifaximin, there was no change in total healthcare costs. Patients adherent to rifaximin incurred $2,891 [$2,340] lower total healthcare costs than non-adherent patients. In a simulated plan of 1 million lives, if 50% of HE patients treated with lactulose alone had rifaximin added on and were adherent to rifaximin therapy, the total cost savings would be $7.5 [$6.1] million per year ($0.62 [$0.50] per-member-per-month). CONCLUSIONS Patients incurred significantly lower rates of HE-related and all-cause hospitalizations during rifaximin versus lactulose episodes, resulting in lower facility and professional costs. Cost savings may be possible if rifaximin adherence is improved in HE patients. LIMITATIONS The study is subject to limitations common to claims-based analyses.