Cost-effectiveness analysis of initial HIV treatment under Italian guidelines

Giorgio L Colombo^1,2, Vincenzo Colangeli³, Antonio Di Biagio⁴, Sergio Di Matteo², Claudio Viscoli⁴, Pierluigi Viale^3
1School of Pharmacy, University of Pavia, Pavia, Italy; ²SAVE - Studi Analisi Valutazioni Economiche, Milan, Italy; ³Clinica Malattie Infettive, Azienda Ospedaliera Sant'Orsola Malpighi Bologna, Alma Mater Studiorum, University of Bologna, Bologna, Italy; ⁴Clinica Malattie Infettive dell'Ospedale San Martino di Genova, University of Genova, Genova, Italy

Introduction: Since the mid-1990s, highly active antiretroviral therapy (HAART) has modified the clinical course of human immunodeficiency virus (HIV) infection, reducing the rate of disease progression, the incidence of opportunistic infections, and mortality. The authors of this paper performed an economic analysis to estimate the cost-effectiveness of the HAART regimens in Italy for managing HIV-infected patients according to national guidelines.
Patients and methods: The incremental cost-effectiveness analysis was carried out by means of a Markov model, which through a decision-analytic approach, made it possible to compare the studied antiretroviral regimens. The population considered in the model consisted of adult subjects with HIV who received antiretroviral HAART treatment for the first time. The population considered in the analysis reflects the patients’ characteristics according to one of the regional surveillance systems HIV/AIDS infection report currently operating in Italy. The analysis was carried out from the point of view of the Italian health care system. The considered outcome measures were quality-adjusted life years (QALYs) and direct health costs calculated for the year 2010. Both the outcomes (QALYs) and the costs were discounted by 3.5%. The time horizon adopted in the model was 10 years.
Results: The model shows, in terms of cost per gained QALY, single tablet regimen (STR) appeared to be the most cost-effective therapeutic choice (€22,017), followed by tenofovir (TDF) + lamivudine + efavirenz (EFV) (€24,526), and TDF/emtricitabine (FTC) + nevirapine (€26,416), and TDF + FTC + EFV (€26,558); the remaining strategies have an incremental costeffectiveness ratio (ICER) value varying from €28,000 to €41,000 per QALY. The sensitivity analysis on the main variables confirmed the validity of the base case scenario.
Conclusion: STR is the most cost-effective treatment strategy, compared with the other therapeutic regimens recommended by the Italian guidelines. All the ICER values of the various regimens considered by the Italian guidelines were lower than the threshold value of €50,000 commonly accepted at the international level. The model developed represents a tool for policy makers and health care professionals to make short- and long-term cost projections and thus evaluate their impact on the available budgets for HIV patients.

Keywords: antiretroviral therapy regimens, single tablet regimens, STR, Markov model, quality-adjusted life years, QALYs, HAART