The health and activities limitation index in patients with acute myocardial infarction

Willingness to Pay per Quality-Adjusted Life Year in a Study of Knee Osteoarthritis

Background. Determining whether a particular medical intervention is cost-effective requires that a threshold of cost per benefit gained be established. As debate continues over the appropriate threshold, we present measures of willingness to pay (WTP) per quality-adjusted life year (QALY) for own health and 2 hypothetical osteoarthritis scenarios. Methods. One hundred ninety-three persons, located through random digit dialing in Harris County, Texas, completed face-to-face interviews collecting demographic information and health preferences using visual analog scale, time tradeoff, standard gamble, and WTP methodologies. Results. The mean WTP/QALY for all methods was lower (range, $1221-$5690/QALY) than many estimates from revealed preference studies and lower than the oft-cited arbitrary cutoff of $50 000. WTP/QALY was highest when participants were judging their personal health improvements as opposed to hypothetical scenarios. There were some significant differences in WTP/QALY across elicitation methodologies for the same scenario. Demographic characteristics were not associated with WTP/QALY measures. Conclusions. The health states and improvements in health evaluated here do not contain a risk of mortality, unlike many situations in which WTP/QALY has been previously evaluated. The lower WTP/QALY values found here may indicate that the presence of a mortality risk reduction substantially increases stated WTP/QALY. Appropriate thresholds for cost-effectiveness may be dependent on the context of a situation, including risk of mortality.

A multicentre randomised controlled trial and economic evaluation of continuous positive airway pressure for the treatment of obstructive sleep apnoea syndrome in older people: PREDICT

BACKGROUND

The therapeutic and economic benefits of continuous positive airway pressure (CPAP) for the treatment of obstructive sleep apnoea syndrome (OSAS) have been established in middle-aged people. In older people there is a lack of evidence.

OBJECTIVE

To determine the clinical efficacy of CPAP in older people with OSAS and to establish its cost-effectiveness.

DESIGN

A randomised, parallel, investigator-blinded multicentre trial with within-trial and model-based cost-effectiveness analysis.

METHODS

Two hundred and seventy-eight patients, aged ≥ 65 years with newly diagnosed OSAS [defined as oxygen desaturation index at ≥ 4% desaturation threshold level for > 7.5 events/hour and Epworth Sleepiness Scale (ESS) score of ≥ 9] recruited from 14 hospital-based sleep services across the UK.

INTERVENTIONS

CPAP with best supportive care (BSC) or BSC alone. Autotitrating CPAP was initiated using standard clinical practice. BSC was structured advice on minimising sleepiness.

COPRIMARY OUTCOMES

Subjective sleepiness at 3 months, as measured by the ESS (ESS mean score: months 3 and 4) and cost-effectiveness over 12 months, as measured in quality-adjusted life-years (QALYs) calculated using the European Quality of Life-5 Dimensions (EQ-5D) and health-care resource use, information on which was collected monthly from patient diaries.

SECONDARY OUTCOMES

Subjective sleepiness at 12 months (ESS mean score: months 10, 11 and 12) and objective sleepiness, disease-specific and generic quality of life, mood, functionality, nocturia, mobility, accidents, cognitive function, cardiovascular risk factors and events at 3 and 12 months.

RESULTS

Two hundred and seventy-eight patients were randomised to CPAP (n = 140) or BSC (n = 138) over 27 months and 231 (83%) patients completed the trial. Baseline ESS score was similar in both groups [mean (standard deviation; SD) CPAP 11.5 (3.3), BSC 11.4 (4.2)]; groups were well balanced for other characteristics. The mean (SD) in ESS score at 3 months was -3.8 (0.4) in the CPAP group and -1.6 (0.3) in the BSC group. The adjusted treatment effect of CPAP compared with BSC was -2.1 points [95% confidence interval (CI) -3.0 to -1.3 points; p < 0.001]. At 12 months the effect was -2.0 points (95% CI -2.8 to -1.2 points; p < 0.001). The effect was greater in patients with increased CPAP use or higher baseline ESS score. The number of QALYs calculated using the EQ-5D was marginally (0.005) higher with CPAP than with BSC (95% CI -0.034 to 0.044). The average cost per patient was £1363 (95% CI £1121 to £1606) for those allocated to CPAP and £1389 (95% CI £1116 to £1662) for those allocated to BSC. On average, costs were lower in the CPAP group (mean -£35; 95% CI -£390 to £321). The probability that CPAP was cost-effective at thresholds conventionally used by the NHS (£20,000 per QALY gained) was 0.61. QALYs calculated using the Short Form questionnaire-6 Dimensions were 0.018 higher in the CPAP group (95% CI 0.003 to 0.034 QALYs) and the probability that CPAP was cost-effective was 0.96. CPAP decreased objective sleepiness (p = 0.02), increased mobility (p = 0.03) and reduced total and low-density lipoprotein cholesterol (p = 0.05, p = 0.04, respectively) at 3 months but not at 12 months. In the BSC group, there was a fall in systolic blood pressure of 3.7 mmHg at 12 months, which was not seen in the CPAP group (p = 0.04). Mood, functionality, nocturia, accidents, cognitive function and cardiovascular events were unchanged. There were no medically significant harms attributable to CPAP.

CONCLUSION

In older people with OSAS, CPAP reduces sleepiness and is marginally more cost-effective than BSC over 12 months. Further work is required in the identification of potential biomarkers of sleepiness and those patients at increased risk of cognitive impairment. Early detection of which could be used to inform the clinician when in the disease cycle treatment is needed to avert central nervous system sequelae and to assist patients decision-making regarding treatment and compliance. Treatment adherence is also a challenge in clinical trials generally, and adherence to CPAP therapy in particular is a recognised concern in both research studies and clinical practice. Suggested research priorities would include a focus on optimisation of CPAP delivery or support and embracing the technological advances currently available. Finally, the improvements in quality of life in trials do not appear to reflect the dramatic changes noted in clinical practice. There should be a greater focus on patient centred outcomes which would better capture the symptomatic improvement with CPAP treatment and translate these improvements into outcomes which could be used in health economic analysis.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN90464927.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 19, No. 40. See the NIHR Journals Library website for further project information.

Exploring the Potential Cost-Effectiveness of Patient Decision Aids for Use in Adults with Obstructive Sleep Apnea

Background. There is increasing evidence highlighting the effectiveness of patient decision aids (PtDAs), but evidence supporting their cost-effectiveness is lacking. We consider patients with obstructive sleep apnea (OSA), in whom a PtDA may decrease nonadherence to treatment by empowering patients to receive the option that is most congruent with their own values. Objective. To determine the potential costs and benefits of delivering a PtDA to patients with moderate OSA. Methods. A Markov cohort decision-analytic model was developed for patients with moderate OSA, comparing a PtDA to usual care over 5 years from a societal perspective. Data for patient preference for treatment options was taken from a recent randomized crossover trial, event data (cardiovascular, motor vehicle accidents) came from national databases and published literature. Potential improvements in adherence are unknown, so we considered a realistic range of values. Outcome measures were 5-year costs (in 2010 Canadian dollars), quality-adjusted life years (QALYs), and the incremental cost-effectiveness ratio (ICER). Results. When adherence to treatment was unchanged, the PtDA strategy was dominated by incurring lower QALYs and higher costs. When nonadherence was decreased by 20% in the PtDA arm (corresponding to an increase in adherence from 63% to 70% for continuous positive airway pressure and from 77% to 82% for mandibular advancement splints in year 1), the ICER fell to $62,414/QALY. Costs associated with the treatment devices and delivering the PtDA had the greatest effect on cost-effectiveness. Limitations. The model relies on surrogate measures and opinions for key parameters. Conclusions: The cost-effectiveness of PtDAs will depend on contextual factors, but a framework is described for properly considering their long-term cost-effectiveness. A number of important questions around the appropriateness of benefit measurement for PtDA trials are highlighted.

A systematic literature review of cardiovascular event utilities

Cardiovascular disease (CVD) results in half of the non-communicable disease-related deaths worldwide. Rising treatment costs have increased the need for cost-utility models designed to compare the value of new and existing therapies. Cost-utility models require utilities, values representing the strength of preferences for various health states. This systematic literature review aimed to identify and evaluate utilities reported for stroke, myocardial infarction (MI) and angina. In total, 83 unique studies were identified that reported utilities for these events. Approximately two-thirds reported utility values for stroke, and most used the EuroQoL five dimension to derive utilities. Utility values were lower in patients who experienced cardiovascular (CV) events than in patients who did not. The utility estimates for each condition varied greatly, likely due to differences in assessment methodologies and patient populations. This variability must be considered when choosing values for cost-utility models. Comparisons among reported utilities are further complicated by inconsistent CV event definitions.

Asthma and serious psychological distress: prevalence and risk factors among US adults, 2001-2007

BACKGROUND

For millions of adults, effective control of asthma requires a regimen of care that may be compromised by psychological factors, such as anxiety and depression. This study estimated the prevalence and risk factors for serious psychological distress (SPD) and explored their relationship to health-related quality of life (HRQOL) among adults with asthma in the United States.

METHODS

We analyzed data from 186,738 adult respondents from the 2001-2007 US National Health Interview Survey. We calculated weighted average prevalence estimates of current asthma and SPD by demographic characteristics and health-related factors. We used logistic regression analysis to calculate odds ratios for factors that may have predicted asthma, SPD, and HRQOL.

RESULTS

From 2001 to 2007, the average annual prevalence of current asthma was 7.0% and the average prevalence of SPD was 3.0%. Among adults with asthma, the prevalence of SPD was 7.5% (95% CI, 7.0%-8.1%). A negative association between HRQOL and SPD was found for all adults, independent of asthma status. A similar pattern of risk factors predicted SPD and the co-occurrence of SPD and asthma, although adults with asthma who reported lower socioeconomic status, a history of smoking or alcohol use, and more comorbid chronic conditions had significantly higher odds of SPD.

CONCLUSION

This research suggests the importance of mental health screening for persons with asthma and the need for clinical and community-based interventions to target modifiable lifestyle factors that contribute to psychological distress and make asthma worse.

Cost-effectiveness of oral appliances in the treatment of obstructive sleep apnoea-hypopnoea

PURPOSE

Oral appliances (OA) are commonly prescribed for the treatment of obstructive sleep apnoea-hypopnoea (OSAH), but there is limited evidence on their cost-effectiveness.

MATERIALS AND METHODS

A model was designed to simulate the costs and benefits of treatment of OSAH with OA or continuous positive airway pressure (CPAP) based on their effects on quality of life, motor vehicle crashes, and cardiovascular effects. The primary outcome was the incremental cost-effectiveness ratio (ICER) in terms of costs per one quality-adjusted life year (QALY) gained 5 years after treatment.

RESULTS

Compared with no treatment, OA results in $268 higher costs and an incremental QALY of 0.0899 per patient (ICER = $2,984/QALY). Compared with OA, CPAP resulted in $1,917 more costs and 0.0696 additional QALYs (ICER = $27,540/QALY). For the most part in the sensitivity analyses, CPAP remained cost-effective compared to OA, and OA remained cost-effective with respect to no treatment in almost all scenarios.

CONCLUSIONS

OAs are less economically attractive than CPAP but remain a cost-effective treatment for patients who are unwilling or unable to adhere to CPAP therapy.

An economic analysis of aspirin desensitization in aspirin-exacerbated respiratory disease

BACKGROUND

Aspirin desensitization is an effective therapy for moderate-to-severe aspirin-exacerbated respiratory disease (AERD). Desensitization also allows the use of aspirin for secondary cardiovascular prevention.

OBJECTIVE

We sought to investigate the cost-effectiveness of aspirin desensitization with subsequent aspirin therapy in patients with AERD.

METHODS

The Healthcare Cost and Utilization Project was used, together with average reimbursements from a large Midwestern health care plan, to model the costs of aspirin desensitization for therapeutic and prophylactic use in patients with AERD. Event probabilities were based on the published literature.

RESULTS

Ambulatory desensitization for AERD cost $6768 per quality-adjusted life year (QALY) saved ($18.54 per additional symptom-free day). Aspirin desensitization for AERD remained cost-effective (<$50,000 per QALY saved) across a wide range of assumptions. When secondary cardiovascular prophylaxis was considered, ambulatory aspirin desensitization was less expensive than an alternative antiplatelet agent, clopidogrel. Clopidogrel cost $106,453 per incremental QALY saved when compared with desensitization.

CONCLUSIONS

Aspirin desensitization is a cost-effective therapeutic intervention in patients with moderate-to-severe AERD. Although the incremental cost-effectiveness of clopidogrel in individuals with aspirin allergy is marginal, if available, ambulatory desensitization remains a less-expensive option for secondary cardiovascular prophylaxis.

Health limitations and quality of life associated with cancer and other chronic diseases by phase of care

OBJECTIVE

To estimate health limitations and health-related quality of life (HRQL) associated with cancer and other chronic conditions in a nationally representative sample within a phase-of-care framework.

STUDY DESIGN AND SETTING

We used a nested case-control design to assess health limitations and HRQL in individuals reporting a breast, colorectal, prostate, or lung cancer diagnosis, or a diagnosis of arthritis, diabetes, heart disease, or hypertension compared with similar controls without these conditions. All subjects were selected from the 1986-1994 National Health Interview Surveys linked to mortality files in 1995, and classified into the initial, continuing, or last year of life phase of care. Health limitations and HRQL were compared for cases and controls for each condition with 2-sided statistical tests.

RESULTS

Across all conditions, individuals in the last year of life phase of care reported greater health limitations and lower HRQL, as measured by the Health Activities and Limitations Index (HALex), than did individuals in the initial and continuing phases of care. Compared with their matched controls, individuals with cancer or other chronic conditions were more likely to report health limitations and lower mean HALex values in the initial, continuing, and last year of life phases of care (P < 0.05).

CONCLUSIONS

We observed greater health limitations and lower HRQL associated with cancer and other chronic diseases compared with similar individuals without these conditions. The phase-of-care framework used in this study seems to be applicable to the assessment of HRQL for cancer and other chronic diseases.

Assessment of the health of Americans: the average health-related quality of life and its inequality across individuals and groups

BACKGROUND

The assessment of population health has traditionally relied on the population's average health measured by mortality related indicators. Researchers have increasingly recognized the importance of including information on health inequality and health-related quality of life (HRQL) in the assessment of population health. The objective of this study is to assess the health of Americans in the 1990s by describing the average HRQL and its inequality across individuals and groups.

METHODS

This study uses the 1990 and 1995 National Health Interview Survey from the United States. The measure of HRQL is the Health and Activity Limitation Index (HALex). The measure of health inequality across individuals is the Gini coefficient. This study provides confidence intervals (CI) for the Gini coefficient by a bootstrap method. To describe health inequality by group, this study decomposes the overall Gini coefficient into the between-group, within-group, and overlap Gini coefficient using race (White, Black, and other) as an example. This study looks at how much contribution the overlap Gini coefficient makes to the overall Gini coefficient, in addition to the absolute mean differences between groups.

RESULTS

The average HALex was the same in 1990 (0.87, 95% CI: 0.87, 0.88) and 1995 (0.87, 95% CI: 0.86, 0.87). The Gini coefficient for the HALex distribution across individuals was greater in 1995 (0.097, 95% CI: 0.096, 0.099) than 1990 (0.092, 95% CI: 0.091, 0.094). Differences in the average HALex between all racial groups were the same in 1995 as 1990. The contribution of the overlap to the overall Gini coefficient was greater in 1995 than in 1990 by 2.4%. In both years, inequality between racial groups accounted only for 4-5% of overall inequality.

CONCLUSION

The average HRQL of Americans was the same in 1990 and 1995, but inequality in HRQL across individuals was greater in 1995 than 1990. Inequality in HRQL by race was smaller in 1995 than 1990 because race had smaller effect on the way health was distributed in 1995 than 1990. Analysis of the average HRQL and its inequality provides information on the health of a population invisible in the traditional analysis of population health.

Burden of illness in cancer survivors: findings from a population-based national sample

BACKGROUND

Population trends in aging and improved cancer survival are likely to result in increased cancer prevalence in the United States, but few estimates of the burden of illness among cancer survivors are currently available. The purpose of this study was to estimate the burden of illness in cancer survivors in a national, population-based sample.

METHODS

A total of 1823 cancer survivors and 5469 age-, sex-, and educational attainment-matched control subjects were identified from the 2000 National Health Interview Survey. Multiple measures of burden, including utility, a summary measure of health, and days lost from work, were compared using two-sided tests of statistical significance for the two groups overall and for subgroups stratified by tumor site and time since diagnosis.

RESULTS

Compared with matched control subjects, cancer survivors had poorer outcomes across all burden measures (P<.01). Cancer survivors had lower utility values (0.74 versus 0.80; P<.001) and higher levels of lost productivity and were more likely to report their health as fair or poor (31.0% versus 17.9%; P<.001) than matched control subjects. Cancer survivors reported statistically significantly higher burden than did control subjects across tumor sites and across time since diagnosis (i.e., within the past year, 2-5 years, 6-10 years, and > or =11 years for the majority of measures.

CONCLUSIONS

Cancer survivors have poorer health outcomes than do similar individuals without cancer across multiple burden measures. These decrements are consistent across tumor sites and are found in patients many years following reported diagnosis. Improved measurement of long-term burden of illness will be important for future prospective research.

Evaluating health utility in patients with melanoma, breast cancer, colon cancer, and lung cancer: a nationwide, population-based assessment

BACKGROUND

Understanding the quality of life and health utility for cancer survivors is important; however, little data are available-particularly for long-term (>5 year) survivors. Using "health utility" scores as a proxy for quality of life may be advantageous because it is a single value. Utility scores range from 1.0 (perfect health) to 0 (death), and have been shown to be a good numerical summary of overall quality of life. Using a validated instrument for health utility (HALex), we calculated and report the scores of four different surgical cancers at multiple periods of follow-up, ranging from <1 year to >5 years after diagnosis.

METHODS

Patients diagnosed with either breast, colon, melanoma, or lung cancer were studied using the 1998 National Health Information Survey. Responses to several validated questions were collected and health utility scores were calculated. Different time periods were measured; acute (<1 year), short term (1-5 years), and long term (>5 years). Once a single health utility score was calculated, multivariate analyses were performed to identify important predictors of better versus worse health utility scores.

RESULTS

The total sample size was 692 (breast 377, colon 169, melanoma 92, lung 54). Mean ages at diagnosis for the cancer groups were 56, 61, 52, and 60 years, respectively. The mean health utility scores in the acute period after diagnosis were: breast 0.62, colon 0.67, melanoma 0.73, and lung 0.42. In this acute period, the mean utility score for lung cancer survivors was statistically lower versus the others in the acute period (P < 0.001). Although variable trends were noted in the short-term period, all cancers demonstrated an increase in mean scores in the long-term period; the percent increases were: breast 15% (P = 0.01), colon 12%, melanoma 7%, and lung 47%. Multivariate regression analyses identified important associations of health utility scores. Significant predictors of lower health utility included the presence of pain and the presence of co-existent diseases, most commonly joint problems, cardiovascular disease, and diabetes.

CONCLUSIONS

For four surgical cancers in three time periods after diagnosis, health utility scores were lowest immediately after treatment and improved over time. Long-term (>5 year) survivors had the highest scores. Additionally, our analyses show that a part of health utility in this cohort is determined by the presence of pain and co-existent diseases, which are often items that can be improved by quality clinical care.