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 < .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.
Keywords: Costs; I; I1; I10; I19; hepatic encephalopathy; hospitalization; lactulose; rifaximin.