The transient nature of utilities and health preferences

A comparison of injured patient and general population valuations of EQ-5D health states for New Zealand

Background

A near-universal finding internationally is that patient valuations of their own health, represented using the EQ-5D system, are mostly higher than general population valuations of the same EQ-5D states. This paper investigates whether this result also applies to New Zealand. Despite the EQ-5D’s widespread use for cost-utility analysis in New Zealand, in particular by the Pharmaceutical Management Agency (PHARMAC) for health technology assessments, no previous studies comparing patient and general population valuations have included data for New Zealand.

Methods

Valuations of 13 EQ-5D health states from a 1999 survey of the New Zealand general population (n = 396) are compared with injured New Zealanders’ (n = 2099) valuations of their own health (also represented on the EQ-5D) collected between 2007 and 2009 in the Prospective Outcomes of Injury Study. Which EQ-5D dimensions are most strongly associated with the population valuations is also investigated.

Results

Injured population valuations are higher (better-rated health) than general population valuations for all 13 health states considered except 11111 (no problems on any EQ-5D dimension). This difference, which tends to be larger the ‘worse’ the state, is statistically significant at the 10% level for most of the states. State 11111 is rated significantly lower by the injured population than the general population. Pain/discomfort is more important in determining valuations for the general population than for injured people, whereas problems with self-care are more important for the injured population; anxiety/depression is important in both general and injured population valuations.

Conclusions

Consistent with the international literature, injured people’s valuations of their own health are mostly higher than the general population’s hypothetical valuations of the same EQ-5D states for New Zealand. These differences are practically significant in the sense that they are larger than minimally important differences for the EQ-5D from the literature, and they appear capable of significantly affecting CUA results.

Elicitation of health state utilities in soft tissue sarcoma

PURPOSE

Soft tissue sarcomas (STS) are uncommon tumours with varying histological subtypes. There is a paucity of available data concerning the quality-of-life (QoL) impact of STS which could be used to support economic evaluation of future treatments. This study aimed to elicit societal utility values for health states that depict the impact of STS and its treatment.

METHODS

Following the development of eight health state vignettes, a sample of 100 members of the UK general public participated in a valuation exercise to elicit utility values using the time trade-off procedure.

RESULTS

The treatment response state was valued as the least burdensome by participants followed by the prospect of stable disease (mean utility value: 0.736 SD 0.21). Serious adverse events were associated with a range of disutilities from -0.236 for grade III/IV pain to -0.357 for grade III/IV nausea/vomiting. Progressive disease was deemed the least desirable outcome and was associated with a substantial decline in utility (-0.473).

CONCLUSIONS

Findings suggest advanced STS are associated with significant burden for individuals. Treatment-related adverse events were seen as debilitating, however, progression represents an enormous challenge to QoL. This illustrates the significant value to individuals of extending the progression free survival period.

Estimating utilities for chronic kidney disease, using SF-36 and SF-12-based measures: challenges in a population of veterans with diabetes

PURPOSE

Using transformations of existing quality-of-life data to estimate utilities has the potential to efficiently provide investigators with utility information. We used within-method and across-method comparisons and estimated disutilities associated with increasing chronic kidney disease (CKD) severity.

METHODS

In an observational cohort of veterans with diabetes (DM) and pre-existing SF-36/SF-12 responses, we used six transformation methods (SF-12 to EQ-5D, SF-36 to HUI2, SF-12 to SF-6D, SF-36 to SF-6D, SF-36 to SF-6D (Bayesian method), and SF-12 to VR-6D) to estimate unadjusted utilities. CKD severity was staged using glomerular filtration rate estimated from serum creatinines, with the modification of diet in renal disease formula. We then used multivariate regression to estimate disutilities specifically associated with CKD severity stage.

RESULTS

Of 67,963 patients, 22,273 patients had recent-onset DM and 45,690 patients had prevalent DM. For the recent-onset group, the adjusted disutility associated with CKD derived from the six transformation methods ranged from 0.0029 to 0.0045 for stage 2; -0.004 to -0.0009 for early stage 3; -0.017 to -0.010 for late stage 3; -0.023 to -0.012 for stage 4; -0.078 to -0.033 for stage 5; and -0.012 to -0.001 for ESRD/dialysis.

CONCLUSION

Disutility did not increase monotonically as CKD severity increased. Differences in disutilities estimated using the six different methods were found. Both findings have implications for using such estimates in economic analyses.

Estimation of utilities in attention-deficit hyperactivity disorder for economic evaluations

BACKGROUND

Attempts to estimate the cost effectiveness of attention-deficit hyperactivity disorder (ADHD) treatments in the past have relied on classifying ADHD patients as responders or non-responders to treatment. Responder status has been associated with a small gain in health-related quality of life (HR-QOL) [or utility, as measured using the generic QOL measure EQ-5D] of 0.06 (on a scale from 0 being dead to 1.0 being full health).

OBJECTIVES

The goal of the present study was to develop and validate several ADHD-related health states, and to estimate utility values measured amongst the general public for those states and to re-estimate utility values associated with responder status.

METHODS

Detailed qualitative interview data were collected from 20 young ADHD patients to characterize their HR-QOL. In addition, item-by-item clinical and HR-QOL data from a clinical trial were used to define and describe four health states (normal; borderline to mildly ill; moderately to markedly ill; and severely ill). ADHD experts assessed the content validity of the descriptions. The states were rated by 100 members of the UK general public using the time trade-off (TTO) interview and visual analog scale. Statistical mapping was also undertaken to estimate Clinical Global Impression-Improvement (CGI-I) utilities (i.e. response status) from Clinical Global Impression-Severity (CGI-S) defined states. The mapping work estimated changes in utilities from study baseline to last visit for patients with a CGI-I score of ≤ 2 or ≤ 3.

RESULTS

The validity of the four health states developed in this study was supported by in-depth interviews with ADHD experts and patients, and clinical trial data. TTO-derived utilities for the four health states ranged from 0.839 (CGI-S state 'normal') to 0.444 (CGI-S state 'severely ill'). From the mapping work, the change in utility for treatment responders was 0.19 for patients with a CGI-I score of ≤ 2 and 0.15 for patients with a CGI-I score of ≤ 3.

CONCLUSIONS

The present study provides utilities for different severity levels of ADHD estimated in a TTO study. This approach provides a more granular assessment of the impact of ADHD on HR-QOL than binary approaches employed in previous economic analyses. Change in utility for responders and non-responders at different levels of CGI-I was estimated, and thus these utilities may be used to compare health gains of different ADHD interventions.

A valuation of infusion therapy to preserve islet function in type 1 diabetes

OBJECTIVES

Recent advances in monoclonal antibody therapies offer the prospect of the prevention or amelioration of type 1 diabetes mellitus (T1DM). The present study was designed to capture UK (English and Scottish) preference weights for the process of undergoing infusion therapy and the likely outcomes of treatment for children (8-12 years), adolescents (13-17 years), and adults.

METHODS

Vignette descriptions of T1DM health states (describing infusion therapy and reduced insulin need) were constructed based on qualitative interviews with people with type 1 diabetes, clinicians and findings from a literature review. Utilities were elicited for each health state using the standard gamble interview from the general public, adults with diabetes, and parents of children with diabetes. Participants also completed other outcome measures-EQ-5D, Pediatric Quality-of-Life Inventory, and Hyperglycemic Fear Survey. Mixed model analyses were used to estimate the influence on utility of different participant characteristics.

RESULTS

Self-report questionnaires indicated the nature and degree of impact of T1DM on adults', adolescents', and children's quality of life, with adolescents reporting the lowest health-related quality-of-life profile of all groups. The mixed model analysis indicated that each health state was a significant predictor of utility and the T1DM participants gave significantly higher utilities compared with the general public (P = 0.02).

CONCLUSION

The general public and people with diabetes (or parents of children with diabetes) all place significant value on reducing the need for insulin injections; also, all recognize the disutility of undergoing infusion cycles. These values are suitable for supporting estimates of cost-effectiveness of infusion therapies in T1DM.

Health state utility scores for cancer-related anemia through societal and patient valuations

OBJECTIVES

Fatigue is recognized as the most serious complication of chemotherapy for the majority of patients. This study aims to determine preferences and utility values for health state descriptions of anemia associated with cancer treatment.

METHODS

FACT-An clinical trial data were summarized to define health states associated with hemoglobin levels of 7.0-8.0, 8.0-9.0, 9.0-10.0, 10.0-10.5, 10.5-11.0, 11.0-12.0, and 12.0+ g/dL. Health state descriptions were reviewed by clinicians and two quality-of-life experts. Eighty-five members of the general public were asked to rate the health states using a visual analogue scale and standard gamble (SG). Twenty-six oncology patients were interviewed using the time trade-off (TTO).

RESULTS

The mean societal SG derived utility values showed a significant linear change from 0.583 +/- 0.067 (7-8 g/dL hemoglobin [Hb]) to 0.708 +/- 0.057 (12+ g/dL Hb). The patient TTO data ranged from 0.297 +/- 0.127 (7-8 g/dL Hb) to 0.611 +/- 0.092 (12+ g/dL Hb).

CONCLUSIONS

The health state utility scores from both groups show a decrement in line with worsening anemia. Furthermore, patients who have experienced cancer-related fatigue rate the more severe levels of anemia much lower than the general public.