Cost-effectiveness of inpatient versus outpatient treatment for substance use disorder in Ethiopia: A societal perspective using a Markov model

Background: Substance use disorders are a growing burden in Ethiopia, contributing to 34% of the non-communicable disease (NCD) burden and accounting for 86% of indirect costs. Current treatment is largely facility based, with two main modalities: inpatient (ITC) and outpatient (OTC). However, the relative cost-effectiveness of these two approaches remains unclear. This study aims to evaluate the cost-effectiveness of ITC versus OTC treatment for SUD in Ethiopia. Methods: A cohort-based Markov model was used to compare the cost-effectiveness of inpatient versus outpatient treatment for SUDs. Costs were assessed from societal perspective, and reported in United States Dollar (US$), 2022. Effectiveness was measured in terms of disability adjusted life year (DALY) averted. Model input parameters were obtained from the literature review and local data. Both the average cost-effectiveness ratio (ACER) and incremental cost-effectiveness ratio (ICER) were calculated. One-way and probabilistic sensitivity analysis was performed to assess the robustness of the findings. The analysis was conducted using Microsoft Excel, with visual basic application (VBA) macros for sensitivity analysis. Results: The baseline cost of ITC was US$33,626 (range: US$26901-40351), while the baseline cost of OTC was US$27,036 (range: US$21629-32444) per patient treated, with comparable effectivenessin terms of DALY averted. The ACER of ITC was US$102, while that of OTC was US$82 per DALY averted. The ICER of ITC compared to OTC was US$3,710 per DALY averted and it exceeds the WHO-CHOICE cost-effectiveness threshold of one to three times Ethiopia’s GDP per capita (US$1027.59). The ICER results were sensitive to changes in treatment cost and effectiveness. Conclusions: The SUD treatment in Ethiopia is associated with a significant financial burden. While OTC is more cost-effective than ITC, it remains largely inaccessible and unaffordable. Integrating SUD services into primary health care could enhance access and reduce costs, with specialized OTC and ITC care reserved for severe cases. Moreover, the management of SUD should be included in the benefit packages of community-based health insurance (CBHI) scheme, to provide financial protection against health expenditures, particularly for the poor.