|Equation||(Number of H.I.V. diagnosed participants) x (Q1: Reduced probability of adequate CD4 cell count due to the intervention) x (Q2: Additional years of life expectancy from improved H.I.V. biomarkers, CD4) x ($ QALY)|
|Explanation||This metric estimates the impact of stable housing on improved health for individuals living with H.I.V., estimated in terms of quality-adjusted life years (QALY).|
Number of H.I.V. diagnosed participants: Reported by program.
Q1: Reduced probability of adequate CD4 cell count due to the intervention: [28%], Galarraga, et al, (2018) this is the reduction in the probability of showing adequate CD4 markers for individuals with stable housing vs. those with unstable housing situations such as living in shelters.
Q2: # additional years of life expectancy from improved H.I.V. biomarkers, CD4: [1.1], based on the findings of Walenski, et al. (2010), we estimated that H.I.V. infected individuals with higher levels of CD4 live 1.1 more years than individuals with lower levels of the biomarker.
$ value per QALY: [$50,000].
Benefits are then discounted to present value based on the average age of participation to life expectancy.
|References||Galárraga, O., et al. (2018). The effect of unstable housing on HIV treatment biomarkers: An instrumental variables approach. Social Science & Medicine, 214, 70–82.|
Walensky, R., et al. (2010). Forecasting the Impact of a Comprehensive HIV Strategy in Washington DC. Clinical Infectious Diseases, 51(4), 392-400.