Research Artcle Journal of Communicable Diseases (P-ISSN: 0019-5138 & E-ISSN: 2581-351X) Copyright (c) 2019: Advanced Research Publicatons Journal of Communicable Diseases Volume 51, Issue 3 - 2019, Pg. No. 1-9 Peer Reviewed & Open Access Journal Corresponding Author: Vishal Deo, Department of Statstcs, Ramjas College, University of Delhi, Delhi, India. E-mail Id: vishaaldeo@gmail.com Orcid Id: htps://orcid.org/0000-0003-3629-0962 How to cite this artcle: Deo V, Grover G. A New Approach to Evaluate Quality Adjusted Life Years using Proxy Utlity Functon - An Applicaton to HIV/ AIDS Data. J Commun Dis 2019; 51(3): 1-9. Date of Submission: 2019-08-01 Date of Acceptance: 2019-10-19 I N F O A B S T R A C T A New Approach to Evaluate Quality Adjusted Life Years using Proxy Utility Function - An Application to HIV/ AIDS Data Vishal Deo 1,2 , Gurprit Grover 2 1 Department of Statstcs, Ramjas College, University of Delhi, Delhi, India. 2 Department of Statstcs, Faculty of Mathematcal Sciences, University of Delhi, Delhi, India. DOI: htps://doi.org/10.24321/0019.5138.201919 Estmaton of Quality Adjusted Life Years (QALYs) is pivotal towards economic evaluation and cost-effectiveness analysis of medical interventons. Most of the methods developed tll date for calculatng QALYs are based on mult-state structures where fxed utlity values are assigned to each disease state and total QALYs are calculated on the basis of total lengths of stay in each state. In this artcle, we have presented a new proxy approach to defne utlity as a functon of risk factors, which can be used to calculate QALY without defning discrete disease states. Retrospectve survival data of HIV/ AIDS patents undergoing treatment at the Antretroviral Therapy (ART) center of Ram Manohar Lohia hospital in New Delhi has been used to demonstrate implementaton of the proposed methodology. Joint modelling, with a mixed efect longitudinal sub-model for CD4 count and a Cox proportonal hazard survival sub-model with tme dependent covariates, has been used to estmate risks associated with diferent factors and covariates. Using the proxy utlites, QALYs have been calculated for each individual for their lifetme tme horizon, defned as the tme since their registraton in the ART tll death or tll their age reach average life expectancy of HIV/ AIDS patents in India. QALY results are consistent with fndings of conventonal cost-efectveness studies on ART for HIV/ AIDS patents in India. Keywords: Cost-Efectveness Analysis, Health Economics, Joint Modelling, HIV/ AIDS, Utlity Functon Introduction Cost-Efectveness Analysis (CEA) is an important health economic technique to evaluate economic feasibility of treatment regimens for desired medical outcomes. CEA is hugely dependent on the calculaton of gain in Quality Adjusted Life Years (QALYs) in patents afer administraton of the treatment regime under review. Quality adjustment is achieved by assigning different utility values to diferent states of the disease on the basis of physical and psychological appraisal of the patents. Most of the research works done on CEA tll date have used either markov models or mult-state models to map disease progression in terms of transitons between pre-defned states. Survival models are used to ft the survival data and