Economic methods for measuring the quality of life associated with HIV infection

The use of health utility in cost-utility analysis: A systematic review in substance use disorders

BACKGROUND AND AIM

We aim to identify within-trial and modelled Cost-Utility Analysis (CUA) in substance use disorders (SUD) and review the applicability assessment associated with health utility used in modelled CUA.

STUDY DESIGN AND METHODS

We searched Medline, Embase, EconLit and the Pharmaceutical Benefits Advisory Committee (PBAC) databases. A global systematic literature search was undertaken to determine the CUA of SUD interventions. Key characteristics of the studies and use of health utility were described. The applicability assessment associated with health utility used in modelled CUA was reviewed using The Health Utility Application Tool (HAT).

RESULTS

The final review retrieved 49 CUA (14 within-trial and 35 modelled CUA). Three major health utility measurements were used - standard gamble, EQ-5D-5L and SF-6D. EQ-5D-5L was mainly used in within-trial CUA, whereas standard gamble, EQ-5D-5L and SF-6D were equally cited in modelled CUA and within-trial CUA. Twenty-nine articles using modelled CUA citing health utilities from published literature were assessed. Only half and one-third of CUA studies described the type of quality-of-life measure and value sets used in health utility studies, respectively. Only two-thirds showed the authors addressed questions about the similarities in clinical conditions, and health state description between health utility studies and economic evaluation studies.

CONCLUSION

Justifications for chosen health utilities in modelled CUA studies were mostly absent in SUD. We suggested health economists use the HAT to make judgements when assessing health utility from published estimates. The use of this tool will increase the reliability of economic evaluation carried out to assist government and policymakers in making informed decisions around health topics.

Patient-Proxy and Societal Perspectives of Quality-of-Life Utilities in Children With Cleft Lip and Palate Managed With Surgical Repair vs No Repair in Ethiopia

IMPORTANCE

In Ethiopia, more than 70% of infants with cleft lip and/or palate (CL/P) lack access to surgery. Infants who are untreated can experience severe malnutrition and extreme social stigma resulting in abandonment. Utilities are standardized measures of health-related quality of life (HRQOL) that inform health care resource allocation. However, CL/P utilities are missing from low- and middle-income countries (LMICs).

OBJECTIVE

To elicit utilities for untreated and surgically treated children with CL/P with consideration for social determinants of health from patient-proxy and societal participants.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study used patient proxies and societal participants in Addis Ababa, Ethiopia, from July 1, 2019, to January 30, 2020. Eligible patient proxies were caregivers of children younger than 18 years with nonsyndromic CL/P who were untreated or received surgery. Proxies were necessary as most patients were 0 to 4 years old and cannot reliably self-report. Eligible societal participants were 18 years and older with no family history of CL/P.

EXPOSURES

Surgical treatment and social determinants of health.

MAIN OUTCOMES AND MEASURES

Participants measured utilities using the visual analog scale (VAS), time trade-off (TTO), and standard gamble (SG).

RESULTS

In this study, 312 patient proxies and 135 societal participants were recruited. Mean (SD) utilities for untreated CL/P ranged from 0.57 (0.23) to 0.70 (0.22) from patient proxies and from 0.35 (0.21) to 0.8 (0.23) from societal participants, depending on utility instrument and cleft type. Surgical treatment was associated with a better HRQOL from the patient-proxy perspective (VAS, 0.17; 95% CI, 0.09 to 0.26; TTO, 0.15; 95% CI, 0.05 to 0.25) from the societal perspective (VAS, 0.21; 95% CI, 0.16 to 0.26; TTO, 0.17; 95% CI, 0.13 to 0.22; SG, 0.11; 95% CI, 0.06 to 0.15). Social determinants of health that were associated with patient-proxy utilities were income above the national mean (VAS, 0.10; 95% CI, 0.02 to 0.17; TTO, 0.11; 95% CI, 0.02 to 0.20), and religion (Christian vs other: TTO, -0.10; 95% CI, -0.17 to -0.03). From the societal perspective, the association between treatment and utilities was smaller in females compared with males (TTO, -0.05; 95% CI, -0.10 to -0.01).

CONCLUSIONS AND RELEVANCE

The findings of this study suggest that CL/P disease severity and surgical impact in Ethiopia were undervalued by previous estimates from high-income countries and were associated with social determinants of health. Utility studies from participants from LMICs are feasible and necessary for representing HRQOL in LMICs and addressing health inequalities.

Risks associated with antiretroviral treatment for human immunodeficiency virus (HIV): qualitative analysis of social media data and health state utility valuation

Purpose

Despite benefits of antiretroviral therapies (ART), people with HIV infection have increased risk of cardiovascular disease, kidney disease, and low bone mineral density. Some ARTs increase risk of these events. The purpose of this study was to examine patients’ perspectives of these risks and estimate health state utilities associated with these risks for use in cost-utility models.

Methods

Qualitative thematic analysis was conducted to examine messages posted to the POZ/AIDSmeds Internet community forums, focusing on bone, kidney, and cardiovascular side effects and risks of HIV/AIDS medications. Then, health state vignettes were drafted based on this qualitative analysis, literature review, and clinician interviews. The health states (representing HIV, plus treatment-related risks) were valued in time trade-off interviews with general population participants in the UK.

Results

Qualitative analysis of the Internet forums documented patient concerns about ART risks, as well as treatment decisions made because of these risks. A total of 208 participants completed utility interviews (51.4% female; mean age 44.6 years). The mean utility of the HIV health state (virologically suppressed, treated with ART) was 0.86. Adding a description of risk resulted in statistically significant disutility (i.e., utility decreases): renal risk (disutility = −0.02), bone risk (−0.03), and myocardial infarction risk (−0.05).

Conclusions

Patient concerns and treatment decisions were documented via qualitative analysis of Internet forum discussions, and the impact of these concerns was quantified in terms of health state utilities. The resulting disutilities may be useful for differentiating among ARTs in economic modeling of treatment for patients with HIV.

Utilities Derived from Visual Analog Scale Scores in Patients with HIV/AIDS

Background. Visual analog scale (VAS) scores are used as global quality-of-life indicators and, unlike true utilities (which assess the desirability of health states v. an external metric), are often collected in HIV-related clinical trials. The purpose of this study was to derive and evaluate transformations relating aggregate VAS scores to utilities for current health in patients with HIV/AIDS. Methods. HIV-specific transformations were developed using linear and nonlinear regression to attain models that best fit mean VAS and standard gamble (SG) utility values directly derived from 299 patients with HIV/AIDS participating in a multicenter study of health values. The authors evaluated the transformations using VAS and SG utility values derived directly from patients in other HIV/AIDS studies. Derived transformations were also compared with published transformations. Results. A simple linear transformation was derived (u = 0.44v + 0.49), as was the exponent for a curvilinear model (u = 1-[1- v ]1.6 ), where u = the sample mean utility and v the sample mean VAS score. The curvilinear transformation predicted values within 0.10 of the actual SG utility in 5 of 8 estimates and within 0.05 in 3 of 8 estimates (absolute error ranged from -0.01 to +0.21). The linear transformation performed some-what better, predicting within 0.10 of the actual SG value in 6 of 8 cases and within 0.05 in 5 of 8 estimates (absolute error ranged from -0.05 to +0.13). An alternative linear model (u =v + 0.018) derived from the literature performed similarly to our linear model (7 of 8 predictions within 0.10, 1 of 8 estimates within 0.05, and absolute error ranging from -0.15 to +0.10), whereas an alternative published curvilinear model (u = 1 - [1 - v ]2.3 ) performed the least well (2 of 8 estimates within 0.10 of the actual values and no estimates within 0.05). Conclusions. Predicted utilities are a reasonable alter-native for use in HIV/AIDS decision analyses and costeffectiveness analyses. Linear transformations performed better than curvilinear transformations in this context and can be used to convert aggregate VAS scores to aggregate SG values in large HIV/AIDS studies that collect VAS data but not utilities.

Prediction of health preference values from CD4 counts in individuals with HIV

BACKGROUND

A common measure of health benefit in technology assessments is the quality-adjusted life year, which incorporates health preference or utility scores.

OBJECTIVE

To build and test a predictive model using CD4 counts to derive health preference scores.

DESIGN

Predictive modeling. Setting. Ontario HIV Treatment Network Cohort Study. Measurement. The relationship between HUI3-derived health preference score and HIV health status measured by CD4 count was examined by a regression model. Additional independent variables considered included age, time since HIV diagnosis, AIDS-defining condition, sex, and education level. A polynomial regression model was fit to predict health preference scores. The final model was established using automated backwards stepwise variable elimination using the Akaike information criterion. Tenfold cross-validation was used to assess the model.

RESULTS

Data from 841 participants were available. Mean age and time since diagnosis were 46.78 and 11.03 years, respectively. CD4 counts ranged from 2 to 995 cells per mm(3) with 267 (31.75%) individuals having less than 350 cells per mm(3). Mean HUI3 utility score was 0.72 and ranged from -0.25 to 1. The final model retained squared terms for CD4 counts, age, and time since HIV diagnosis and eliminated history of AIDS-defining condition and the nonsquared time since HIV diagnosis. Prediction error was assessed in 14 subgroups using the validation set. Two subgroups had mean prediction errors greater than 0.02. Limitations. All statistical models are limited by the data used to develop and test the model. The model estimates health utility scores primarily through CD4 counts. Therefore, the model may be inappropriate if noninfectious diseases are a significant factor.

CONCLUSIONS

Results provide a model for predicting health preference values from CD4 counts.

Health related quality of life among patients with tuberculosis and HIV in Thailand

Introduction

Health utilities of tuberculosis (TB) patients may be diminished by side effects from medication, prolonged treatment duration, physical effects of the disease itself, and social stigma attached to the disease.

Methods

We collected health utility data from Thai patients who were on TB treatment or had been successfully treated for TB for the purpose of economic modeling. Structured questionnaire and EuroQol (EQ-5D) and EuroQol visual analog scale (EQ-VAS) instruments were used as data collection tools. We compared utility of patients with two co-morbidities calculated using multiplicative model (U_CAL) with the direct measures and fitted Tobit regression models to examine factors predictive of health utility and to assess difference in health utilities of patients in various medical conditions.

Results

Of 222 patients analyzed, 138 (62%) were male; median age at enrollment was 40 years (interquartile range [IQR], 35–47). Median monthly household income was 6,000 Baht (187 US$; IQR, 4,000–15,000 Baht [125–469 US$]). Concordance correlation coefficient between utilities measured using EQ-5D and EQ-VAS (U_EQ-5D and U_VAS, respectively) was 0.6. U_CAL for HIV-infected TB patients was statistically different from the measured U_EQ-5D (p-value<0.01) and U_VAS (p-value<0.01). In tobit regression analysis, factors independently predictive of U_EQ-5D included age and monthly household income. Patients aged ≥40 years old rated U_EQ-5D significantly lower than younger persons. Higher U_EQ-5D was significantly associated with higher monthly household income in a dose response fashion. The median U_EQ-5D was highest among patients who had been successfully treated for TB and lowest among multi-drug resistant TB (MDR-TB) patients who were on treatment.

Conclusions

U_CAL of patients with two co-morbidities overestimated the measured utilities, warranting further research of how best to estimate utilities of patients with such conditions. TB and MDR-TB treatments impacted on patients' self perceived health status. This effect diminished after successful treatment.

Quality of life of patients with advanced HIV/AIDS: measuring the impact of both AIDS-defining events and non-AIDS serious adverse events

OBJECTIVE

To investigate the relative magnitude and duration of impact of AIDS-defining events (ADEs) and non-AIDS serious adverse events (SAEs) on health-related quality of life (HRQoL) among patients with advanced HIV/AIDS.

METHODS

We use data from OPTIMA (OPTions In Management with Antiretrovirals), a multinational, randomized, open, control, clinical management trial of treatment strategies for patients with multidrug-resistant HIV and advanced immune disease. Longitudinal models were used to determine the effects of ADEs and SAEs on HRQoL across periods before, during, and after event onset. The Medical Outcomes Study HIV Health Survey (MOS-HIV) physical and mental health summary scores (MOS-PHS and MOS-MHS), EQ-5D, and the Health Utilities Index Mark 3 HRQoL measures were all assessed at regular follow-up intervals during the trial.

RESULTS

ADEs occurred much less frequently than SAEs (n = 147 vs. n = 821) in the study sample population of 368 patients, during median follow-up of 3.96 years. Although both ADEs and SAEs had significant negative impacts on HRQoL, SAEs had at least as large an impact upon HRQoL as ADEs when both were included in a multivariate linear regression model, controlling for other covariates. However, the effect of ADEs on HRQoL was more persistent, with larger magnitude of effect across all instruments in time intervals further from the onset of the event.

CONCLUSIONS

Non-AIDS SAEs occurring in patients with late-stage HIV/AIDS seem to have at least as important an immediate impact on patient HRQoL as ADEs; however, the impact of ADEs seems to be more persistent. Our findings call for a greater emphasis on the detection and active prevention of non-AIDS SAEs in patients with late-stage HIV/AIDS.

The concurrent validity and responsiveness of the health utilities index (HUI 3) among patients with advanced HIV/AIDS

OBJECTIVES

To assess the concurrent validity and responsiveness of the Health Utility Index 3 (HUI3) in patients with advanced HIV/AIDS, and to determine the responsiveness of this measure, the MOS-HIV and EQ-5D to HIV-related clinical events.

METHODS

Data from the OPTIMA (OPTions In Management with Antiretrovirals) trial was analyzed. Two aspects of the validity of the HUI3 were considered: concurrent validity was evaluated using Spearman correlations with MOS-HIV component and summary scores. Responsiveness to AIDS-defining events (ADE) and all adverse events (our external change criterion) was assessed using area under the receiver operating characteristic (AUROC) curves.

RESULTS

The study enrolled 368 patients (mean follow-up: 3.66 years); 82% had at least one severe adverse event and 27% had at least one ADE. The HUI3 scale and items showed good concurrent validity, with 85% of the expected relationships with the MOS-HIV subscales verified. The HUI3 was responsive to both adverse events (AUROC [95%CI]: 0.68 [0.57, 0.80]) and ADEs (0.62 [0.51, 0.74]). The EQ-5D was responsive to ADEs (0.66 [0.56, 0.76]), but not responsive to adverse events (0.56 [0.46, 0.68]).

CONCLUSION

The HUI3 is a valid and responsive measure of the change in HRQoL associated with clinical events in an advanced HIV/AIDS population.

Health-related quality of life in a randomized trial of antiretroviral therapy for advanced HIV disease

OBJECTIVE

To assess and compare alternative approaches of measuring preference-based health-related quality of life (HRQoL) in treatment-experienced HIV patients and evaluate their association with health status and clinical variables.

DESIGN

Cross-sectional study.

SETTING

Twenty-eight Veterans Affairs hospitals in the United States, 13 hospitals in Canada, and 8 hospitals in the United Kingdom.

PATIENTS

Three hundred sixty-eight treatment-experienced HIV-infected patients enrolled in the Options in Management with Antiretrovirals randomized trial.

MEASUREMENTS

Baseline sociodemographic and clinical indicators and baseline HRQoL using the Medical Outcome Study HIV Health Survey (MOS-HIV), the EQ-5D, the EQ-5D visual analog scale (EQ-5D VAS), the Health Utilities Index Mark 3 (HUI3), and standard gamble (SG) and time trade-off (TTO) techniques.

RESULTS

The mean (SD) baseline HRQoL scores were as follows: MOS-HIV physical health summary score 41.70 (11.16), MOS-HIV mental health summary score 44.76 (11.38), EQ-5D 0.77 (0.19), HUI3 0.59 (0.32), EQ-5D VAS 65.94 (21.71), SG 0.75 (0.29), and TTO 0.80 (0.31). Correlations between MOS-HIV summary scores and EQ-5D, EQ-5D VAS, and HUI3 ranged from 0.60 to 0.70; the correlation between EQ-5D and HUI3 was 0.73; and the correlation between SG and TTO was 0.43. Preference-based HRQoL scores were related to physical, mental, social, and overall health as measured by MOS-HIV. Concomitant medication use, CD4 cell count, and HIV viral load were related to some instruments' scores.

CONCLUSIONS

On average, preference-based HRQoL for treatment-experienced HIV patients was decreased relative to national norms but also highly variable. Health status and clinical variables were related to HRQoL.

Utility assessment of HIV/AIDS-related health states in HIV-infected Ugandans

OBJECTIVE

To assess the psychometric performance of using standard gamble (SG), time trade-off (TTO) and visual analogue scale (VAS) in the evaluation of three predetermined HIV/AIDS health states in HIV-infected Ugandans, for use in cost-effectiveness analyses.

METHODS

We recruited participants with CD4 cells <200/microl from the Development of AntiRetroviral Therapy in Africa (DART) trial cohort [randomized trial evaluating antiretroviral therapy (ART) management strategies] in Uganda, before they initiated ART (n = 276). A comparison group of ART-naive HIV-infected individuals was recruited from the Entebbe Cohort study (n = 159). Participants were interviewed and asked to rate his/her own health state using VAS; rank and evaluate HIV/AIDS predetermined health states using TTO and SG relative to an improved health state. Tools were tested for psychometrical properties.

RESULTS

Women constituted 64% and 76% of the DART and Entebbe Cohorts. Mean age was 36.5 and 36.7 years, respectively. Participants could discriminate between predetermined HIV/AIDS health states. Deterioration in health status was associated with a reduction in rating scores (VAS), increased willingness to give up time (TTO) and acceptance of increased risk (SG) to achieve a better health state, independent of the participant's actual health state, as measured by CD4 cell counts.

CONCLUSION

VAS, TTO and SG have good psychometric properties, making them good candidates for use in resource-constrained settings. Further research in a wider population is necessary to generate an evidence base with which to inform resource allocation decisions.

Can urban methadone patients complete health utility assessments?

OBJECTIVE

To assess the ability of methadone maintenance treatment (MMT) patients to use two standardized health assessment tools to value health states related to chronic hepatitis C virus (HCV) infection and HCV treatment-associated side effects. An estimated 65-90% of MMT patients are chronically infected with HCV.

METHODS

We employed qualitative methods to explore how patients completed computerized rating scale assessments and standard gamble utility assessments by (1) having them discuss their responses in a think-aloud interview immediately after each health state assessment, and (2) allowing them the opportunity to recalibrate prior responses after considering subsequent health states.

RESULTS

MMT patients used the rating scale boundaries appropriately and used the standard gamble to rank the health states in an a priori logical order. A guided assessment approach that allowed recalibration provided additional insight into values assigned to the health states presented.

CONCLUSION

MMT patients are able to perform the tasks associated with rating scale assessments and standard gamble utility assessments of HCV health states.

PRACTICE IMPLICATIONS

These assessment methods should be considered as a means to elicit MMT patients' values for HCV treatment, since the treatment outcome is uncertain but it is likely that side effects will adversely affect current health.

The cost-effectiveness of counseling strategies to improve adherence to highly active antiretroviral therapy among men who have sex with men

OBJECTIVE

Inadequate adherence to highly active antiretroviral therapy (HAART) may lead to poor health outcomes and the development of HIV strains that are resistant to HAART. The authors developed a model to evaluate the cost-effectiveness of counseling interventions to improve adherence to HAART among men who have sex with men (MSM).

METHODS

The authors developed a dynamic compartmental model that incorporates HIV treatment, adherence to treatment, and infection transmission and progression. All data estimates were obtained from secondary sources. The authors evaluated a counseling intervention given prior to initiation of HAART and before all changes in drug regimens, combined with phone-in support while on HAART. They considered a moderate-prevalence and a high-prevalence population of MSM.

RESULTS

If the impact of HIV transmission is ignored, the counseling intervention has a cost-effectiveness ratio of $25,500 per quality-adjusted life year (QALY) gained. When HIV transmission is included, the cost-effectiveness ratio is much lower: $7400 and $8700 per QALY gained in the moderate- and high-prevalence populations, respectively. When the intervention is twice as costly per counseling session and half as effective as estimated in the base case (in terms of the number of individuals who become highly adherent, and who remain highly adherent), then the intervention costs $17,100 and $19,600 per QALY gained in the 2 populations, respectively.

CONCLUSIONS

Counseling to improve adherence to HAART increased length of life, modestly reduced HIV transmission, and cost substantially less than $50,000 per QALY gained over a wide range of assumptions but did not reduce the proportion of drug-resistant strains. Such counseling provides only modest benefit as a tool for HIV prevention but can provide significant benefit for individual patients at an affordable cost.

Clinical and Economic Outcomes of Nonadherence to Highly Active Antiretroviral Therapy in Patients With Human Immunodeficiency Virus

BACKGROUND

Nonadherence with highly active antiretroviral therapy (HAART) is common in typical human immunodeficiency virus (HIV) patient care settings, but the consequences have not been well described. This study aimed to quantify the clinical and economic effects of nonadherence and estimate the cost-effectiveness of improving adherence in treatment-naive HIV patients.

METHODS

A Markov model was developed to project quality-adjusted life expectancy and direct medical costs for patients on an initial once-daily regimen of efavirenz, lamivudine, and stavudine XR. The model compared 2 adherence scenarios: "ideal" (based on clinical trials) and "typical" (based on observational studies in actual practice). Disease progression was a function of viral load, CD4 count, and adherence. Data on HIV natural history, treatment benefits, costs, and utilities were derived from the literature.

RESULTS

With typical adherence, patients lose 1.2 quality-adjusted life years (QALYs) that could be gained with ideal adherence. Improving adherence to ideal levels is cost-effective at 29,400 US dollars/QALY gained. As much as 1,600 US dollars/y per patient could be spent on an intervention to improve adherence to ideal levels, and the incremental cost-effectiveness would remain less than 50,000 US dollars/QALY gained. A cost-effectiveness ratio of 50,000 US dollars/QALY is a commonly accepted minimum standard for cost-effective medical interventions in the United States, although many experts believe this standard has drifted upwards over time.

CONCLUSIONS

Typical adherence with HAART reduces quality-adjusted life expectancy by 12% compared with ideal adherence. Interventions to improve adherence appear to be a highly cost-effective use of resources.

The effect of diagnosis with HIV infection on health-related quality of Life

We sought to understand how diagnosis with HIV affects health-related quality of life. We assessed health-related quality of life using utility-based measures in a Department of Veterans Affairs (VA) clinic and a University-based clinic. Respondents assessed health-related quality of life regarding their current health, and retrospectively assessed their health 1 month prior to and 2 months after diagnosis with HIV infection. Sixty-six patients completed the study. The overall mean utilities for health 1 month before and 2 months after diagnosis were 0.87 (standard error 0.037), and 0.80 (0.043) (p<0.005 by rank sign test), but the effect of diagnosis differed between the two clinics, with a substantial decrease in the university clinic and a small non-significant decrease in the VA clinic. The overall mean utility for current health was 0.85 (0.034), assessed on average 7.5 years after diagnosis. When asked directly whether diagnosis of HIV decreased health-related quality of life, 47% agreed, but 35% stated that HIV diagnosis positively affected health-related quality of life. Diagnosis with HIV decreased health-related quality of life at 2 months on average, but this effect diminished over time, and differed among patient populations. Years after diagnosis, although half of the patients believed that diagnosis reduced health-related quality of life, one-third reported improved health-related quality of life.

A comparative review of health-related quality-of-life measures for use in HIV/AIDS clinical trials

With the advent of highly active antiretroviral therapy (HAART), HIV-infected patients are living longer and are concerned not only with a treatment's ability to extend their life but also with the quality of the life they are able to lead. Regulatory authorities are also paying closer attention to the use of health-related quality-of-life (HR-QOL) measures in clinical trials and to the subsequent claims that are made based on the results. This paper reviews existing HR-QOL measures reported in the HIV/AIDS literature since 1990 and identifies those most worthy of consideration for use in future clinical trials.A comprehensive review following predefined selection criteria was conducted. Generic and HIV-targeted measures were assessed for content and practicality for the clinical trial setting. The generic measures were additionally reviewed for the ability to produce preference-based index scores and for the existence of normative general population data. Three generic and six HIV-targeted measures met these selection criteria and were then assessed more fully in terms of their development (HIV-targeted measures), psychometric properties and appropriateness for use in clinical trials.It was determined that each of the selected generic measures (i.e. Medical Outcomes Study [MOS] 36-Item Short Form Survey Instrument [SF-36], EQ-5D, Health Utilities Index [HUI]) could serve as a useful adjunct to an HIV-targeted measure in a trial. The Functional Assessment of HIV Infection (FAHI) and MOS-HIV health survey were deemed the two most appropriate HIV-targeted measures. Each of the measures can be self-administered in < or = 10 minutes and there was ample evidence of their excellent psychometric properties. However, they would not be optimal in all HIV-infected subgroups (e.g. treatment naive vs advanced; adolescents vs older adults) targeted for clinical trial interventions. Although there is no one best HR-QOL measure for use in HIV/AIDS clinical trials, based on our review criteria we identified three generic and two HIV-targeted candidate measures. However, these measures have their limitations and it is clear that greater consensus needs to develop regarding more effective and efficient approaches to HR-QOL measurement in HIV/AIDS clinical trials. Along with the increasingly complex HR-QOL measurement task resulting from changes in the HIV-infected population and shifts in the HR-QOL burden associated with HIV infection and its treatment over the past 25 years, it is increasingly important that HR-QOL outcomes become viable endpoints in HIV/AIDS clinical trials.

Health related quality of life in genital herpes: a pilot comparison of measures

BACKGROUND

Genital herpes (GH) is a common sexually transmitted infection. Novel tools for the control of GH (for example, tests and vaccines) are emerging, but optimal assessment of the cost effectiveness of such interventions requires scaled, preference based estimates of the impact of GH on health related quality of life.

METHODS

We provided self administered interviews to 39 individuals with recurrent GH recruited from an STD clinic and a GH support group in southern Ontario, Canada. Health preference estimates were generated using visual analogue scales (VAS), a time-tradeoff approach (TTO) and the Health Utilities Index Mark-II (HUI-II). Quality of life was also assessed with the Recurrent Genital Herpes Quality of Life scale (RGHQoL).

RESULTS

Average (SD) health values for asymptomatic and symptomatic genital herpes were 0.89 (0.21) and 0.89 (0.22) using TTO, and 0.76 (0.30) and 0.71 (0.30) using VAS. Health utility estimates generated with HUI-II for transient symptomatic and asymptomatic health states were 0.93 (0.08) and 0.80 (0.16). Log transformed health value estimates exhibited convergent validity when compared to RGHQoL, as did health utility estimates for symptomatic GH. Utility scores for symptomatic GH increased (improved) with increasing age; no other subject characteristic was predictive of preference weights.

CONCLUSIONS

Preference based measures of health related quality of life can be elicited with relative ease in the context of genital herpes, and preference weights are correlated with quality of life scores generated using the RGHQoL. Generation of preference weights will permit direct comparison of the economic attractiveness of herpes prevention interventions with that of other commonly available health interventions.

Potential cost-effectiveness of a preventive hepatitis C vaccine in high risk and average risk populations in Canada

Hepatitis C virus (HCV) vaccine development remains at an early stage. We explored the economic and health consequences of potential HCV vaccines by comparing universal vaccination with a hepatitis C vaccine to no vaccination in two groups: (1) injecting drug users (IDU); (2) all 12 year olds, using a Markov cohort simulation. Among IDUs, vaccination would avert 248 cases of HCV infection and 89 HCV-related deaths per 1000 individuals, and reduce costs. In average risk cohorts, vaccination did not reduce costs but was reasonably cost effective. These results provide encouragement to vaccine developers that a vaccine that is moderately effective and reasonably priced should not face economic barriers to implementation and will be attractive to third party payers.

A catalog of dermatology utilities: a measure of the burden of skin diseases

Utilities are measures of quality of life that reflect the strength of individuals' preferences or values for a particular health outcome. As such, utilities represent a measure of disease burden. The aim of this article is to introduce the concept of utilities to the dermatology community and to present a catalog of dermatology utilities obtained from direct patient interviews. Our data are based on 236 total subjects from Grady Hospital (Atlanta, GA), Stanford Medical Center (Palo Alto, CA), and Parkland Hospital (Dallas, TX). The mean time trade-off utilities ranged from 0.640 for blistering disorders to 1.000 for alopecia, cosmetic, and urticaria. The mean utility across all diagnoses was 0.943. We present utilities for 17 diagnostic categories and discuss the underlying reasons for the significant disease burden that these utilities represent. We also present these dermatology categories relative to noncutaneous diseases to place the cutaneous utilities in perspective and to compare the burden of disease. We have demonstrated that skin diseases have considerable burden of disease and provided a preliminary repository of utility data for future researchers and policy makers.

Cost-effectiveness of transfusion of platelet components prepared with pathogen inactivation treatment in the United States

BACKGROUND

The Intercept Blood System (IBS) for platelets has been developed to reduce pathogen transmission risks during transfusions.

OBJECTIVE

This study was a comprehensive economic analysis of the cost-effectiveness of using the IBS for single-donor apheresis platelets (AP) and random-donor pooled platelet concentrates (PC) versus AP and PC without the IBS in the United States in patient populations in which platelets are commonly transfused.

METHODS

All data used in this analysis were summarized from existing published sources (primarily indexed in MEDLINE) and data on file at Baxter Healthcare Corporation (Chicago, Illinois) and Cerus Corporation (Concord, California). A literature-based decision-analytic model was developed to assess the economic costs and clinical outcomes associated with the use of AP and PC treated with the IBS for several conditions and procedures that account for a considerable proportion of the platelet usage in the United States: acute lymphocytic leukemia, non-Hodgkin's lymphoma, coronary artery bypass graft, and hip arthroplasty Risks of infection with HIV, hepatitis C virus (HCV), hepatitis B virus, human T-cell lymphotropic virus type 1, or bacterial agents were incorporated into the model. Possible benefits of reduction of the risk of emerging HCV like pathogens and elimination of the need for gamma irradiation were explored in sensitivity analyses.

RESULTS

The incremental cost per quality-adjusted life-year gained by using AP + IBS versus untreated AP ranged from 1,308,833 dollars to 4,451,650 dollars (without bacterial testing) and 4,759,401 dollars to 22,968,066 dollars (with bacterial testing). Corresponding figures for PC + IBS versus untreated PC ranged from 457,586 dollars to 1,816,060 dollars. Inclusion of emerging HCV like virus and the elimination of the need for gamma irradiation improved the cost-effectiveness to a range of 177,695 dollars to 1,058,127 dollars for AP without bacterial testing, 176,572 dollars to 1,330,703 dollars for AP with bacterial testing, and 22,888 dollars to 153,564 dollars for PC. The model was most likely to be affected by mortality from bacterial contamination, IBS effect on platelet utilization, and the inclusion of potential benefits (ie, gamma irradiation and/or emergent HCV-like virus). The model was relatively insensitive to changes in the IBS price and viral transmission risks.

CONCLUSIONS

The cost-effectiveness of pathogen inactivation via the IBS for platelets is comparable to that of other accepted blood safety interventions (eg, nucleic acid amplification technology). The IBS for platelets may be considered a desirable strategy to increase the safety of platelet transfusions and a potential insurance against the threat of emerging pathogens.

Commentary on using the SF-36 or MOS-HIV in studies of persons with HIV disease

The purpose was to compare and comment on use of the SF-36 and MOS-HIV instruments in studies of persons with HIV disease. Three medical information databases were searched to identify examples of HIV studies that included the MOS-HIV or SF-36. Thirty-nine and 14 published articles were identified for illustration in comparing the use of the MOS-HIV and SF-36 in HIV disease, respectively. Support for the reliability and construct validity of the MOS-HIV and SF-36 was found. Ceiling and floor effects were reported for both the MOS-HIV and SF-36; however, ceiling effects were more common for the MOS-HIV, in part due to fewer items in the physical, social, and role functioning domains. The MOS-HIV measures three domains hypothesized to be associated with the health deterioration of HIV disease not measured by the SF-36; however, these domains may not assess aspects of HIV disease that typify the majority of the persons with HIV disease today. National norms for the U.S. adult population (and other nations) are available for the SF-36. In addition, the SF-36 has been used in a wide variety of patient populations, enabling comparisons of HIV-infected persons with persons with other health conditions. No national norms for the MOS-HIV are available. We conclude that there is currently insufficient evidence in the literature to recommend the use of the MOS-HIV over the SF-36 in HIV-infected persons. Although the SF-36 is not targeted at HIV, it may be preferable to use the SF-36 over the MOS-HIV due to fewer ceiling effects, availability of national norms, and the vast amount of data for other populations in the U.S. and around the world. Head-to-head comparisons demonstrating the unique value of the MOS-HIV over the SF-36 are clearly needed. More importantly, additional work needs to be directed at comparing the MOS-HIV and other putatively HIV-targeted instruments to one another to help demarcate aspects of HRQOL that are truly generic versus specific to HIV disease. Using both a generic and targeted HRQOL measure is a good general strategy, but this has not been a typical practice in studies of HIV because the MOS-HIV is so similar in content to the SF-36.

A meta-analysis of utility estimates for HIV/AIDS

The authors performed a meta-analysis to derive pooled utilities for HIV/AIDS and to assess the relative importance of study design characteristics in predicting utilities. Twenty-five articles were identified reporting 74 unique utilities elicited from 1956 respondents. The authors used a hierarchical linear model to perform the meta-analysis, with disease stage, elicitation method, respondent type, and the upper-bound and lower-bound labels for the utility scale as the independent variables. Disease stage (P = 0.016) and respondent type (P = 0.014) were significant predictors of utility. Elicitation method was of marginal significance (P = 0. 052). Bounds were not significant. Pooling utilities, the authors estimate a utility of 0.70 for AIDS, 0.82 for symptomatic HIV and 0.94 for asymptomatic HIV when the time tradeoff method is used to elicit utilities from patients and the scale ranges from death to perfect health. The pooled utilities reported here should be of great use to researchers performing cost-utility analyses of interventions for HIV/AIDS.

iMPACT3: Internet-based development and administration of utility elicitation protocols

iMPACT3 (Internet Multimedia Preference Assessment Instrument Construction Tool, version 3) is a software development environment that helps researchers build Internet-capable multimedia utility elicitation software programs. The program is a free, openly accessible Web site (http.// preferences.ucsd.edu/impact3/asp). To develop a utility elicitation software program using iMPACT3, a researcher selects modular protocol components from a library and custom tailors the components to the details of his or her research protocol. iMPACT3 builds a Web site implementing the protocol and downloads it to the researcher's computer. In a study of 75 HIV-infected patients, an iMPACT3-generated protocol showed substantial evidence of construct validity and good internal consistency (logic error rates of 4% to 10% and procedural invariance error rates of 10% to 28%, depending on the elicitation method) but only fair 3- to 6-week test-retest reliability (intraclass correlation coefficient= 0.42 to 0.55). Further work may be needed on specific utility assessment procedures, but this study's results confirm iMPACT3's feasibility in facilitating the collection of health state utility data.

Associations of self-reported oral health with physical and mental health in a nationally representative sample of HIV persons receiving medical care

BACKGROUND

The impact of oral health on HIV patients has not been sufficiently documented.

OBJECTIVE

To estimate the associations between measures of oral and generic health-related quality of life in persons receiving medical care for HIV.

DESIGN

This is a longitudinal study of interview data collected in a probability sample of adults with HIV receiving health care in the US. The data were collected at three points in time.

PATIENTS

Two thousand eight hundred and sixty-four HIV-infected adults using medical care.

MEASUREMENTS

Physical and mental health were assessed using 28 items and oral health was assessed using seven items on oral-related pain and discomfort, worry, appearance, and function. Clinical measures included CD4 count, oral symptoms, physical symptoms, and stage of HIV. Physical functioning and emotional well-being were measured on a 0-100 scale with higher scores indicating better health. Oral health was measured using seven items with a five point scale.

RESULTS

In multivariate analyses, oral symptoms had the strongest association with oral health-related quality of life. Each additional oral symptom was associated with an average decrease in oral health (0-100 possible range) of 3.97 points (p = 0.000). In addition, oral health was significantly associated with both physical and mental health. A one-point increase in oral health was associated with a 0.05 (p = 0.000) increase in mental health and 0.02 increase in physical health (p = 0.031).

CONCLUSIONS

Oral health is strongly associated with physical and mental health but provides noteworthy unique information in persons with HIV infection. Thus, physical and mental health measures of HIV patients should incorporate indicators of oral functioning and well-being.

Optimal investment in a portfolio of HIV prevention programs

OBJECTIVES

In this article, the authors determine the optimal allocation of HIV prevention funds and investigate the impact of different allocation methods on health outcomes.

METHODS

The authors present a resource allocation model that can be used to determine the allocation of HIV prevention funds that maximizes quality-adjusted life years (or life years) gained or HIV infections averted in a population over a specified time horizon. They apply the model to determine the allocation of a limited budget among 3 types of HIV prevention programs in a population of injection drug users and nonusers: needle exchange programs, methadone maintenance treatment, and condom availability programs. For each prevention program, the authors estimate a production function that relates the amount invested to the associated change in risky behavior.

RESULTS

The authors determine the optimal allocation of funds for both objective functions for a high-prevalence population and a low-prevalence population. They also consider the allocation of funds under several common rules of thumb that are used to allocate HIV prevention resources. It is shown that simpler allocation methods (e.g., allocation based on HIV incidence or notions of equity among population groups) may lead to alloctions that do not yield the maximum health benefit.

CONCLUSIONS

The optimal allocation of HIV prevention funds in a population depends on HIV prevalence and incidence, the objective function, the production functions for the prevention programs, and other factors. Consideration of cost, equity, and social and political norms may be important when allocating HIV prevention funds. The model presented in this article can help decision makers determine the health consequences of different allocations of funds.

Psychometric evaluation of four HIV disease-specific quality-of-life instruments

OBJECTIVE

To provide a comparative evaluation of psychometric properties for three or more HIV disease-specific quality-of-life (QoL) instruments.

METHODS

Four instruments were selected using the following criteria: multiple publiations of instrument, focus of instrument on QoL, psychometric validation publication or comparison with prevoiusly validated questionnaire, stages of HIV/AIDS used or evaluated in the study, and inclusion of sample items or the instrument in at least one publication. The four HIV-specific QoL instruments were: HIV/AIDS-Targeted Quality of Life Instrument, Medical Outcomes Study HIV questionnaire (MOS-HIV), Functional Assessment of Human Immunodeficiency Virus Infection, and HIV Overview of Problems -- Evaluation System. These instruments were evaluated using combined criteria derived from McHorney and Tarlov and Shumaker et al. The criteria include: administration, content, depth, reliability, validity, and responsiveness. A letter grade scale (A,B,C,D) was used in rating the criteria.

RESULTS

No instrument demonstrated ideal psychometric properties. The MOS-HIV questionnaire was the only instrument that published results for seven of the eight categories. Therefore, a decision cannot be made about the best instrument to use for measuring QoL in an HIV-positive patient.

CONCLUSIONS

Published data for these questionnaires had common limitations of sample size, study design, and population demograhpics, Hence, further testing of these questionnaires is recommended before use in any study to determine suitability, reliability and validity.

Decision analysis with cumulative prospect theory

BACKGROUND

Individuals sometimes express preferences that do not follow expected utility theory. Cumulative prospect theory adjusts for some phenomena by using decision weights rather than probabilities when analyzing a decision tree.

METHODS

The authors examined how probability transformations from cumulative prospect theory might alter a decision analysis of a prophylactic therapy in AIDS, eliciting utilities from patients with HIV infection (n = 75) and calculating expected outcomes using an established Markov model. They next focused on transformations of three sets of probabilities: 1) the probabilities used in calculating standard-gamble utility scores; 2) the probabilities of being in discrete Markov states; 3) the probabilities of transitioning between Markov states.

RESULTS

The same prophylaxis strategy yielded the highest quality-adjusted survival under all transformations. For the average patient, prophylaxis appeared relatively less advantageous when standard-gamble utilities were transformed. Prophylaxis appeared relatively more advantageous when state probabilities were transformed and relatively less advantageous when transition probabilities were transformed. Transforming standard-gamble and transition probabilities simultaneously decreased the gain from prophylaxis by almost half. Sensitivity analysis indicated that even near-linear probability weighting transformations could substantially alter quality-adjusted survival estimates.

CONCLUSION

The magnitude of benefit estimated in a decision-analytic model can change significantly after using cumulative prospect theory. Incorporating cumulative prospect theory into decision analysis can provide a form of sensitivity analysis and may help describe when people deviate from expected utility theory.