Quality-adjusted Life-year Scale Research Articles

Preference heterogeneity in health valuation: a latent class analysis of the Peru EQ-5D-5L values

BackgroundPreference heterogeneity in health valuation has become a topic of greater discussion among health technology assessment agencies. To better understand heterogeneity within a national population, valuation studies may identify latent groups that place different absolute and relative importance (i.e., scale and taste parameters) on the attributes of health profiles.ObjectiveUsing discrete choice responses from a Peruvian valuation study, we estimated EQ-5D-5L values on a quality-adjusted life-year (QALY) scale accounting for latent heterogeneity in scale and taste, as well as controlling heteroskedasticity at task level variation.MethodWe conducted a series of latent class analyses, each including the 20 main effects of the EQ-5D-5L and a power function that relaxes the constant proportionality assumption (i.e., discounting) between value and lifespan. Taste class membership was conditional on respondent-specific characteristics and their experience with the composite time trade-off (cTTO) tasks. Scale class membership was conditional on behavioral characteristics such as survey duration and self-stated difficulty level in understanding tasks. Each analysis allowed the scale factor to vary by task type and completion time (i.e., heteroskedasticity).ResultsThe results indicated three taste classes: a quality-of-life oriented class (33.35%) that placed the highest value on levels of severity, a length-of-life oriented class (26.72%) that placed the highest value on lifespan, and a middle class (39.71%) with health attribute effects lower than the quality class and lifespan effect lower than the length-of-life oriented class. The EQ-5D-5L values ranged from − 2.11 to 0.86 (quality-of-life oriented class), from − 0.38 to 1.02 (middle class), and from 0.36 to 1.01 (length-of-life oriented class). The likelihood of being a member of the quality-of-life class was highly dependent on whether the respondent completed the cTTO tasks (p-value < 0.001), which indicated that the cTTO tasks might cause the Peru respondents to inflate the burden of health problems on a QALY scale compared to those who did not complete the cTTO tasks. The results also showed two scale classes as well as heteroskedasticity within each scale class.ConclusionAccounting for taste and scale classes simultaneously improveds understanding of preference heterogeneity in health valuation. Future studies may confirm the differences in taste between classes in terms of the effect of quality of life and lifespan attributes. Furthermore, confirmatory evidence is needed on how behavioral variables captured within a study protocol may enhance analyses of preference heterogeneity.

Estimating an EQ-5D-Y-3L Value Set for Indonesia by Mapping the DCE onto TTO Values.

Methods for estimating health values in adult populations are well developed, but lag behind in children. The EuroQol standard protocol to arrive at value sets for the youth version of the EQ-5D-Y-3L combines discrete choice experiments with ten composite time trade-off values. Whether ten composite time trade-off values are sufficient remains to be seen and this is one of the reasons the protocol allows for experimental expansion. In this study, 23 health states were administered for the composite time trade-off. This methodological research is embedded in a study aimed at generating a representative value set for EQ-5D-Y-3L in Indonesia. A representative sample of 1072 Indonesian adults each completed 15 discrete choice experiment choice pairs via face-to-face interviews. The discrete choice experiment responses were analysed using a mixed-logit model. To anchor the discrete choice experiment values onto the full health-dead quality-adjusted life-year scale, composite time trade-off values were separately obtained from 222 adults living in Java for 23 EQ-5D-Y-3L states. The derived latent discrete choice experiment values were mapped onto the mean observed composite time trade-off values to create a value set for the EQ-5D-Y-3L. Linear and non-linear mapping models were explored to estimate the most efficient and valid model for the value set. Coefficients obtained from the choice model were consistent with the monotonic structure of the EQ-5D-Y-3L instrument. The composite time trade-off data showed non-linearity, as the values for the two worst states being evaluated were much lower than predicted by a standard linear model estimated over all composite time trade-off data. Thus, the non-linear mapping strategies with a power term outperformed the linear mapping in terms of mean absolute error. The final model gave a value range from 1.000 for full health (11111) to -0.086 for the worst health state (33333). Values were most affected by pain/discomfort and least by self-care. This article presents the first EQ-5D-Y-3L value set for Indonesia based on the stated preferences of adults asked to consider their views about a 10-year-old child. Mapping the mixed-logit discrete choice experiment model with the inclusion of a power term (without a constant) allowed us to generate a consistent value set for Indonesian youth. Our findings support the expansion of the composite time trade-off part of the EQ-5D-Y valuation study design and show that it would be wise to account for possible non-linearities in updates of the design.

A Value Set for the EQ-5D-Y-3L in the Netherlands.

Background and ObjectiveThere is increasing interest in preference-accompanied measures of health for paediatric populations. The child-friendly EQ-5D version, EQ-5D-Y-3L, is one such instrument, but the lack of a Dutch value set prevents its use in economic evaluations of healthcare interventions in the Netherlands. This study aims at covering this gap by collecting preferences using a standardised protocol for deriving EQ-5D-Y-3L value sets.MethodsComposite time trade-off data were collected using videoconferencing interviews, with each respondent completing ten composite time trade-off tasks. Discrete choice experiment data were collected using an online survey, with respondents each completing 15 paired comparisons. Respondents completed these tasks considering what they prefer for a hypothetical 10-year-old child. Discrete choice experiment data were analysed using a ten-parameter mixed-logit model and anchored to the quality-adjusted life-year scale using the mean observed composite time trade-off values.ResultsThe study collected preferences for 197 respondents using composite time trade-off and for 959 respondents using a discrete choice experiment. The discrete choice experiment sample was representative for the Dutch population in terms of age and sex. The level 3 weight for pain/discomfort was the largest, followed by feeling worried, sad or unhappy, usual activities, mobility and self-care. Health state values ranged between −0.218 and 1.ConclusionsThis study generated a Dutch value set for the EQ-5D-Y-3L, which can be used for the computation of quality-adjusted life-years for economic evaluations of healthcare interventions in paediatric populations.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40273-022-01192-0.

Adolescent valuation of CARIES-QC-U: a child-centred preference-based measure of dental caries

ObjectivesThis study develops an adolescent value set for a child-centred dental caries-specific measure of oral health-related quality of life (OHRQoL) based upon CARIES-QC (Caries Impacts and Experiences Questionnaire for Children). This study develops a new approach to valuing child health by eliciting adolescent preferences and anchoring these onto the 1–0 full health-dead QALY (quality adjusted life year) scale using ordinal adult preferences.MethodsTwo online surveys were created to elicit preferences for the CARIES-QC classification system. The first comprised best–worst scaling (BWS) tasks for completion by adolescents aged 11–16 years. The second comprised discrete choice experiment tasks with a duration attribute (DCETTO) for completion by adults aged over 18 years. Preferences were modelled using the conditional logit model. Mapping regressions anchored the adolescent BWS data onto the QALY scale using adult DCETTO values, since the BWS survey data alone cannot generate anchored values.Results723 adolescents completed the BWS survey and 626 adults completed the DCETTO survey. The samples were representative of UK adolescent and adult populations. Fully consistent and robust models were produced for both BWS and DCETTO data. BWS preferences were mapped onto DCETTO values, resulting utility estimates for each health state defined by the classification system.ConclusionThis is the first measure with predetermined scoring based on preferences to be developed specifically for use in child oral health research, and uses a novel technique to generate a value set using adolescent preferences. The estimates can be used to generate QALYs in economic evaluations of interventions to improve children’s oral health.

Incorporating Mortality in Health Utility Measures.

The creation of multiattribute health utility systems requires design choices that have profound effects on the utility model, many of which have been documented and studied in the literature. Here we describe one design choice that has, to the best of our knowledge, been unrecognized and therefore ignored. It can emerge in any multiattribute decision analysis in which one or more essential outcomes cannot be described in terms of the multiattribute space. In health applications, the state of being dead is such an outcome. When the remaining health is conceptualized as a multidimensional space, determining the utility of the state of being dead requires using the interval-scale properties of cardinal utility, combined with elicited utilities for the state of being dead and the all-worst state, to produce a utility function in which the state of being dead has a utility of 0 and full health has a utility of 1 (i.e., the quality-adjusted life-year scale). Although previously unrecognized, there are two approaches to accomplish that step, and they produce different results in almost all cases. As a corollary, the choice of approach determines the proportion of states rated as worse than dead by the system. For example, in the Health Utility Index 3 (HUI3), the method used classifies 78% of the 972,000 unique health states in the classification system as worse than dead, and that proportion increases to 85% when the HUI3 is recalculated using the alternative approach. Studies of populations with significant morbidity are the most likely to be sensitive to the design choice. Those who design utility measures should be aware that they are using a researcher degree of freedom when they decide how to scale the state of being dead.

Using the Choice Sequence in Time Trade-Off as Discrete Choices: Do the Two Stories Match?

ObjectivesThe EQ-5D-5L valuation protocol recommends combining time trade-off (TTO) and discrete choice experiments (DCEs). DCEs that include a duration attribute (DCETTO) allow modeling on the quality-adjusted life-year scale. Because the choice sequence in a TTO can be construed as a series of DCETTO, we used data from a single TTO study to investigate the extent to which DCE values match TTO values when based on identical preferences. MethodsIn a TTO design in which a fixed set of choices were administered without termination at preference indifference, 202 individuals each valued 10 EQ-5D health states. From identified indifference points, we estimated three sets of TTO values: (i) plotting means and (ii) applying censored regressions at −1 and 1. Using all strict preferences, we (iii) estimated DCETTO values with a logit model and a bootstrap procedure. ResultsEstimated DCETTO and TTO values agreed well at the severe end of the quality-adjusted life-year scale, but with decreasing severity, DCETTO values were higher than TTO-values, with the difference peaking at 0.37 for the mildest health state. Left-censoring TTO values at −1 worsen the agreement for the worst health states and did not affect health states. Right censoring at 1 improved the agreement for mild states. ConclusionsTTO and the DCETTO values estimated from the same preference data diverged, with increasing difference for milder health states. Although the values converged when applying censored regression at +1, we question the validity of this adjustment.

Scoring the Child Health Utility 9D instrument: estimation of a Chinese child and adolescent-specific tariff.

To derive children and adolescents' preferences for health states defined by the Chinese version of Child Health Utility 9D (CHU9D-CHN) instrument in China that can be used to estimate quality-adjusted life years (QALYs) for economic evaluation. A profile case best-worst scaling (BWS) and a time trade-off (TTO) method were combined to derive a Chinese-specific tariff for the CHU9D-CHN. The BWS survey recruited students from primary and high schools using a multi-stage random sampling method and was administered in a classroom setting, whilst the TTO survey adopted an interviewer-administrated conventional TTO task and was administered to a convenience sample of undergraduate students. A latent class modelling framework was adopted for analysing the BWS data. Two independent surveys were conducted in Nanjing, China, including a valid sample of 902 students (mean age 13years) from the BWS survey and a valid sample of 38 students (mean age 18years) from the TTO survey. The poolability of the best and the worst responses was rejected and the optimal result based on the best responses only. The optimal model suggests the existence of two latent classes. The BWS estimates were further re-anchored onto the QALY scale using the TTO generated health state values via a mapping approach. This study provides further insights into the use of the BWS method to generate health state values with young people and highlights the potential different decision rules that young people may employ for determining best vs. worst choices in this context.

PP2 - Choice Defines Qalys: A US Valuation of the EQ-5D-5L

Background The 5-level version of the EQ-5D (EQ-5D-5L) was introduced as an improvement on the original 3-level version (EQ-5D-3L). To date, 6 country-specific value sets have been published for EQ-5D-5L and 9 US value sets have been published for other instruments. Our aims were to (1) produce EQ-5D-5L values on a quality-adjusted life year (QALY) scale from the perspective of US adults and (2) compare them with US EQ-5D-3L values and the other country-specific EQ-5D-5L values. Methods In 2016, 8222 US respondents from all 50 states and Washington, DC completed an online survey including a discrete choice experiment with 20 paired comparisons. Each comparison asked respondents, Which do you prefer? regarding a pair of alternatives described using EQ-5D-5L and lifespan attributes. On the basis of more than 50 choices on each of the 3160 pairs, we estimated EQ-5D-5L values on a QALY scale and compared them with the US EQ-5D-3L values and the other country-specific EQ-5D-5L values. Results Ranging from -0.287 (55555) to 0.992 (11121) on a QALY scale, the estimated EQ-5D-5L values were similar to the US EQ-5D-3L values. Compared with the US EQ-5D-3L values, the values exhibited greater sensitivity and specificity and higher correlation with the EQ-5D-5L values of other countries, particularly England. Conclusions Like previous US valuation studies, this study produced nationally representative EQ-5D-5L values on a QALY scale. The results further demonstrate the advantages of the EQ-5D-5L over its 3-level predecessor as a preference-based summary measure of health-related quality of life from the perspective of US adults.

Quality-Adjusted Life-Years without Constant Proportionality

BackgroundA quality-adjusted life-year is a common unit of measurement in health valuation. Under its constant proportionality assumption, the value of a quality-adjusted life span is defined as the product of preference weight and life span. ObjectivesTo empirically identify an alternative functional relationship between life span and value by relaxing the constant proportionality assumption. MethodsUsing an online survey, 5367 respondents completed 30 to 40 paired comparisons where each involved a choice between two health outcomes: one with a longer life span and health problems (five-level EuroQol five-dimensional questionnaire) and the other with a shorter life span and no problems (time trade-off pair). Using 2670 pairs, a saturated model with indicator variables for 27 life spans and 90 health problems of varying duration and severity was estimated by maximum likelihood. Its coefficients empirically illustrate the relationship between life span and value on a quality-adjusted life-year scale. ResultsThe results reject constant proportionality (P < 0.01) and support the use of a power function to describe the relationship between life span and value, namely, value = preference weight × life spanβ. The estimate of power (β = 0.415; 95% confidence interval 0.41–0.42) appears to depend on whether life span was expressed in a temporal unit of days (0.403), weeks (0.509), months (0.541), or years (0.654). ConclusionsRaising life span to a power less than 1 implies decreasing marginal value of life span and greatly improved model fit, and confirms previous violations of proportionality. This power function may replace conventional assumptions in health valuation studies. Nevertheless, governmental agencies may favor a longer time horizon than that of the general population.

Examining the Value of Menopausal Symptom Relief Among US Women

BackgroundMenopausal symptoms can cause significant distress to women, yet little is known about the value women place on these symptoms. MethodsIn April 2013, 3397 US women, aged 40 to 69 years, completed an online survey that included 30 paired comparisons. Specifically, respondents were shown two menopausal symptoms described using the Patient-Reported Outcomes Version of the Common Terminology Criteria for Adverse Events and asked, “Which do you prefer?” From their choices, we estimated a generalized linear model to assess the values women place on symptom relief in terms of quality-adjusted life-years (QALYs). ResultsApproximately half the respondents (1753 of 3397 [52%]) always preferred a reduced lifespan (up to 90 days) instead of experiencing menopausal symptoms at their worst for 30 days. For most of the symptoms (248 of 263 [94%]), including low-grade events, QALYs were significantly reduced (P < 0.05). The value women placed on relief ranged widely by symptom domain: the relief from depression, problems with memory, headache, pain in abdomen, problems with anger, and vomiting were the most valuable. ConclusionsOverall, the value women place on menopausal symptom relief is surprisingly high. As the first national study to directly ask women about their preferences and to estimate the value of menopausal symptom relief on a QALY scale, this work provides critical evidence for health outcomes research in midlife women and can be applied in the evaluation of treatments that reduce or eliminate menopausal symptoms. This work also provides proof-of-concept for an approach to value Patient-Reported Outcomes Version of the Common Terminology Criteria for Adverse Events responses on a QALY scale.

Unchained melody: revisiting the estimation of SF-6D values

In the original SF-6D valuation study, the analytical design inherited conventions that detrimentally affected its ability to predict values on a quality-adjusted life year (QALY) scale. Our objective is to estimate UK values for SF-6D states using the original data and multi-attribute utility (MAU) regression after addressing its limitations and to compare the revised SF-6D and EQ-5D value predictions. Using the unaltered data (611 respondents, 3503 SG responses), the parameters of the original MAU model were re-estimated under three alternative error specifications, known as the instant, episodic, and angular random utility models. Value predictions on a QALY scale were compared to EQ-5D3L predictions using the 1996 Health Survey for England. Contrary to the original results, the revised SF-6D value predictions range below 0 QALYs (i.e., worse than death) and agree largely with EQ-5D predictions after adjusting for scale. Although a QALY is defined as a year in optimal health, the SF-6D sets a higher standard for optimal health than the EQ-5D-3L; therefore, it has larger units on a QALY scale by construction (20.9% more). Much of the debate in health valuation has focused on differences between preference elicitation tasks, sampling, and instruments. After correcting errant econometric practices and adjusting for differences in QALY scale between the EQ-5D and SF-6D values, the revised predictions demonstrate convergent validity, making them more suitable for UK economic evaluations compared to original estimates.

Valuation of Child Behavioral Problems from the Perspective of US Adults.

To assess preferences between child behavioral problems and estimate their value on a quality-adjusted life year (QALY) scale. Respondents, age 18 or older, drawn from a nationally representative panel between August 2012 and February 2013 completed a series of paired comparisons, each involving a choice between 2 different behavioral problems described using the Behavioral Problems Index (BPI), a 28-item instrument with 6 domains (Anxious/Depressed, Headstrong, Hyperactive, Immature Dependency, Anti-social, and Peer Conflict/Social Withdrawal). Each behavioral problem lasted 1 or 2 years for an unnamed child, age 7 or 10 years, with no suggested relationship to the respondent. Generalized linear model analyses estimated the value of each problem on a QALY scale, considering its duration and the child's age. Among 5207 eligible respondents, 4155 (80%) completed all questions. Across the 6 domains, problems relating to antisocial behavior were the least preferred, particularly the items related to cheating, lying, bullying, and cruelty to others. The findings are the first to produce a preference-based summary measure of child behavioral problems on a QALY scale. The results may inform both clinical practice and resource allocation decisions by enhancing our understanding of difficult tradeoffs in how adults view child behavioral problems. Understanding US values also promotes national health surveillance by complementing conventional measures of surveillance, survival, and diagnoses.

PIH40 - Valuation Of Child Health-Related Quality Of Life In The United States

Many economic analyses fail to incorporate evidence on child health-related quality of life because of a paucity of quality-adjusted life year (QALY) estimates. This health valuation study is the first to summarize the EQ-5D-Y on a QALY scale. Drawn from a nationally representative panel, 5207 adult respondents were asked to choose between two losses in child health-related quality of life. Based on their choices, a 1-year increase in child pain/discomfort from 'some' to 'a lot' equals a loss of 4 QALYs (95% CI, 3.8-4.4). Likewise, a 1-year increase in child anxiety/depression from 'a bit' to 'very worried, sad, or unhappy' equals a loss of 2 QALYs (95% CI, 1.9-2.2). These findings enable the integration of child-reported outcomes with adult preferences to inform economic analysis. Results inform both clinical practice and resource allocation decisions by enhancing understanding of difficult tradeoffs in child-reported outcomes. Copyright © 2015 John Wiley & Sons, Ltd.

Valuation of Child Health-Related Quality of Life in the United States.

Many economic analyses fail to incorporate evidence on child health-related quality of life because of a paucity of quality-adjusted life year (QALY) estimates. This health valuation study is the first to summarize the EQ-5D-Y on a QALY scale. Drawn from a nationally representative panel, 5207 adult respondents were asked to choose between two losses in child health-related quality of life. Based on their choices, a 1-year increase in child pain/discomfort from 'some' to 'a lot' equals a loss of 4 QALYs (95% CI, 3.8-4.4). Likewise, a 1-year increase in child anxiety/depression from 'a bit' to 'very worried, sad, or unhappy' equals a loss of 2 QALYs (95% CI, 1.9-2.2). These findings enable the integration of child-reported outcomes with adult preferences to inform economic analysis. Results inform both clinical practice and resource allocation decisions by enhancing understanding of difficult tradeoffs in child-reported outcomes. Copyright © 2015 John Wiley & Sons, Ltd.

The Value Adults Place on Child Health and Functional Status

ObjectivesTo summarize the value adults place on child health and functional status and provide a new quantitative tool that enhances our understanding of the benefits of new health technologies and illustrates the potential contributions of existing data sets for comparative effectiveness research in pediatrics. MethodsRespondents, ages 18 years and older, were recruited from a nationally representative panel between August 2012 and February 2013 to complete an online survey. The survey included a series of paired comparisons that asked respondents to choose between child health and functional status outcomes, which were described using the National Survey of Children with Special Health Care Needs, a 14-item descriptive system of child health outcomes. Using respondent choices regarding an unnamed 7- or 10-year-old child, generalized linear model analyses estimated the value of child health and functional status on a quality-adjusted life-year scale. ResultsAcross the domains of health and functional status, repeated or chronic physical pain, feeling anxious or depressed, and behavioral problems (such as acting out, fighting, bullying, or arguing) were most valuable, as indicated by adult respondents’ preference of other health problems to avoid outcomes along these domains. DiscussionThese findings may inform comparative effectiveness research, health technology assessments, clinical practice guidelines, and public resource allocation decisions by enhancing understanding of the value adults place on the health and functional status of children. ConclusionsImproved measurement of public priorities can promote national child health by drawing attention to what adults value most and complementing conventional measures of public health surveillance.

US Valuation of Health Outcomes Measured Using the PROMIS-29

ObjectivesHealth valuation studies enhance economic evaluations of treatments by estimating the value of health-related quality of life (HRQOL). The Patient-Reported Outcomes Measurement Information System (PROMIS) includes a 29-item short-form HRQOL measure, the PROMIS-29. MethodsTo value PROMIS-29 responses on a quality-adjusted life-year scale, we conducted a national survey (N = 7557) using quota sampling based on the US 2010 Census. Based on 541 paired comparisons with over 350 responses each, pair-specific probabilities were incorporated into a weighted least-squared estimator. ResultsAll losses in HRQOL influenced choice; however, respondents valued losses in physical function, anxiety, depression, sleep, and pain more than those in fatigue and social functioning. ConclusionsThis article introduces a novel approach to valuing HRQOL for economic evaluations using paired comparisons and provides a tool to translate PROMIS-29 responses into quality-adjusted life-years.

A comparison of methods for converting DCE values onto the full health-dead QALY scale.

Preference elicitation techniques such as time trade-off (TTO) and standard gamble (SG) receive criticism for their complexity and difficulties of use. Ordinal techniques such as discrete choice experiment (DCE) are arguably easier to understand but generate values that are not anchored onto the full health-dead 1-0 quality-adjusted life-year (QALY) scale required for use in economic evaluation. This article compares existing methods for converting modeled DCE latent values onto the full health-dead QALY scale: 1) anchoring DCE values using dead as valued in the DCE and 2) anchoring DCE values using TTO value for worst state to 2 new methods: 3) mapping DCE values onto TTO and 4) combining DCE and TTO data in a hybrid model. Models are compared using their ability to predict mean TTO health state values. We use postal DCE data (n = 263) and TTO data (n = 307) collected by interview in a general population valuation study of an asthma condition-specific measure (AQL-5D). New methods 3 and 4 using mapping and hybrid models are better able to predict mean TTO health state values (mean absolute difference [MAD], 0.052-0.084) than the anchor-based methods (MAD, 0.075-0.093) and were better able to predict mean TTO health state values even when using in their estimation a subsample of the available TTO data. These new mapping and hybrid methods have a potentially useful role for producing values on the QALY scale from data elicited using ordinal techniques such as DCE for use in economic evaluation that makes best use of the desirable properties of each elicitation technique and elicited data. Further research is encouraged.

Discrete Choice Modeling for the Quantification of Health States: The Case of the EQ-5D

Objectives Probabilistic models have been developed to establish the relative merit of subjective phenomena by means of specific judgmental tasks involving discrete choices (DCs). The attractiveness of these DC models is that they are embedded in a strong theoretical measurement framework and are based on relatively simple judgmental tasks. The aim of our study was to determine whether the values derived from a DC experiment are comparable to those obtained using other valuation techniques, in particular the time trade-off (TTO). Methods Two hundred nine students completed several tasks in which we collected DC, rank, visual analog scale, and TTO responses. DC data were also collected in a general population sample (N = 444). The DC experiment was designed using a Bayesian approach, and involved 60 choices between two health states and a comparison of all health states to being dead. The DC data were analyzed using a conditional logit and a rank-ordered logit model, relying, respectively, on TTO values and the value for being dead to anchor the DC-derived values to the 0 to 1 quality-adjusted life-year (QALY) scale. Results Although modeled DC data broadly replicated the pattern found in TTO responses, the DC consistently produced higher values. The two methods for anchoring DC-derived values on the QALY scale produced similar results. Conclusions On the basis of the high level of comparability between DC-derived values and TTO values, future valuation studies based on a combination of these two techniques may be considered. The results further suggest that DC can potentially be used as a substitute for TTO.

Impact of hip and vertebral fractures on quality-adjusted life years.

The objective of the study was to estimate the impact of hip and vertebral fractures on quality of life in postmenopausal women using a preference-based health measure that is appropriate for economic evaluations and to investigate correlates of health outcome. Interviews to assess health-related quality of life, which also documented other health conditions and characteristics, were undertaken in women age 50 years and older without osteoporotic fractures compared with women with hip and/or vertebral fracture(s). Health status was characterized by self-reported physical limitations and the mental and physical component summary scores of the SF-36. Quality-adjusted life years (QALYs), which reflect each individual's assessment of her overall health utility, were estimated with time tradeoff values. Regression methods were used to examine QALY correlates (e.g. time since fracture) for each fracture group and to estimate differences in QALYs between fracture and non-fracture subjects after accounting for other patient characteristics. Among 382 women ages 50-96 years, fracture subjects were significantly older, less likely to use hormone replacement therapy and more likely to report physical limitations than non-fracture subjects. On the QALY scale, where 1 represents perfect health and 0 represents death, mean QALY values were 0.82 (95% CI: 0.76, 0.87) among 114 women with one or more vertebral fractures and 0.63 (95% CI: 0.52, 0.74) among 67 with hip fracture compared with 0.91 (95% CI: 0.88, 0.94) among 201 women without fracture. No significant correlates of QALYs were identified among women with vertebral fracture alone. Among hip fracture subjects, time since hip fracture and presence of a vertebral fracture were significant correlates of QALYs. In multiple regression analyses, estimated QALY differences (fracture minus non-fracture subjects) ranged from -0.05 to -0.55 and were equivalent to losses of 20-58 days, 23-65 days and 115-202 days per year for vertebral fracture (p = 0.001), hip fracture (p = 0.009) and hip plus vertebral fracture (p<0.001) subjects, respectively, depending on age. Thus to adequately assess the cost-effectiveness of osteoporosis treatment, the negative impact of vertebral fractures on QALYs, even among women who have survived a hip fracture, must be considered.

Principles of economic analysis.

Principles of economic analysis.