The cost utility analysis of riluzole for the treatment of amyotrophic lateral sclerosis in the UK

Health-related quality of life across disease stages in patients with amyotrophic lateral sclerosis: results from a real-world survey

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is characterized by a rapid disease course, with disease severity being associated with declining health-related quality of life (HRQoL) in persons living with ALS (pALS). The main objective of this study was to assess the impact of disease progression on HRQoL across King's, Milano-Torino Staging (MiToS), and physician-judgement clinical staging. Additionally, we evaluated the impact of the disease on the HRQoL of care partners (cALS).

METHODS

Data were sourced from the Adelphi ALS Disease Specific Programme (DSP)™, a cross-sectional survey of neurologists, pALS and cALS presenting in a real-world clinical setting between July 2020 and March 2021 in Europe and the United States.

RESULTS

Neurologists (n = 142) provided data for 880 pALS. There were significant negative correlations between all three clinical staging systems and EuroQol (European Quality of Life) Five Dimension Five Level Scale (EQ-5D-5L) utility scores and visual analogue scale (VAS) ratings. Although not all differences were significant, 5-item Amyotrophic Lateral Sclerosis Assessment Questionnaire (ALSAQ-5) scores showed a stepwise increase in HRQoL impairment at each stage of the disease regardless of the staging system. At later stages, high levels of fatigue and substantial activity impairment were reported. As pALS disease states progressed, cALS also experienced a decline in HRQoL and increased burden.

CONCLUSIONS

Across outcomes, pALS and cALS generally reported worse outcomes at later stages of the disease, highlighting an unmet need in this population for strategies to maximise QoL despite disease progression. Recognition and treatment of symptoms such as pain and fatigue may lead to improved outcomes for pALS and cALS.

The economic evaluation of ALS care: quality and cost

Objective: The study aims to analyze the quality of studies that make economic evaluations for amyotrophic lateral sclerosis (ALS). Assessing the quality of studies can guide policy-making and planning. Methods: One of the most recognized checklists "The Consensus on Health Economic Criteria" (CHEC)-list designed by Evers et al. in 2005 aims to answer two important questions: is the methodology of the study appropriate, and are the results of the study valid? We reviewed studies focusing on ALS and its economic costs, and evaluated the studies with (CHEC)-list. Results: We examined 25 articles in terms of their cost evaluation and quality. It is seen that they mainly focus on medical costs, ignoring social care costs. When the quality of the studies is examined, it is seen that the studies overall achieve high scores in terms of their purpose and research question, but some of the studies score low in terms of ethical dimension, comprehensiveness of expenditure items, their application of sensitivity analyses and their study design. Conclusions: The main recommendation of our study for future cost evaluation studies is that they should focus on the questions in the checklist that are scored low overall by the 25 articles, and consider the social care costs as well as medical costs. Our recommendations when designing cost studies can be applied to other chronic diseases with long-term economic costs like ALS.

Deconstructing progression of amyotrophic lateral sclerosis in stages: a Markov modeling approach

OBJECTIVES

Propose an empirical amyotrophic lateral sclerosis (ALS) staging approach called Fine'til 9 (FT9) based on how many of the patient's ALS functional rating scale (ALSFRS-R) subscores are 9 or less (of normal 12). Gain insights into progression of ALS by applying Markov models to ALS stages by multiple systems (King's, Milan-Torino system (MITOS) and FT9).

METHODS

Patients from the Pooled Resource Open-Access ALS Clinical Trials (PRO-ACT) dataset were staged using ALSFRS-R responses. Risks of progression through stages and death were estimated, as were effects of prognostic variables on these risks.

RESULTS

A total of 29,947 time points in 3199 patients from the PRO-ACT dataset were assigned stages. Although the three systems were moderately correlated, MITOS stages were heavily skewed toward advanced disease, whereas King's and FT9 stages were more balanced. Non-sequential progression was observed with King's system. Markov models adequately described transitions from stage to stage in the first year of observation, but underestimated risks beyond that point. Regardless of staging method, initial rate of ALSFRS-R decline had a powerful effect on rate of progression through sequential stages, whereas age predominantly influenced stage-specific mortality.

CONCLUSION

King's and FT9 are more sensitive to observed progression of disease in clinical trials than MITOS. FT9 can partition the course similar to King's, and may have advantages of sequential progression and easy applicability to retrospective data. Markov transition intensity estimates may be of value for counseling, health economic studies, and research design. In particular, this framework permits estimation of multidimensional effects of variables (including treatment) on outcome.

Economic Studies in Motor Neurone Disease: A Systematic Methodological Review

BACKGROUND

Motor neurone disease (MND) is a devastating condition which greatly diminishes patients' quality of life and limits life expectancy. Health technology appraisals of future interventions in MND need robust data on costs and utilities. Existing economic evaluations have been noted to be limited and fraught with challenges.

OBJECTIVE

The aim of this study was to identify and critique methodological aspects of all published economic evaluations, cost studies, and utility studies in MND.

METHODS

We systematically reviewed all relevant published studies in English from 1946 until January 2016, searching the databases of Medline, EMBASE, Econlit, NHS Economic Evaluation Database (NHS EED) and the Health Economics Evaluation Database (HEED). Key data were extracted and synthesised narratively.

RESULTS

A total of 1830 articles were identified, of which 15 economic evaluations, 23 cost and 3 utility studies were included. Most economic studies focused on riluzole (n = 9). Six studies modelled the progressive decline in motor function using a Markov design but did not include mutually exclusive health states. Cost estimates for a number of evaluations were based on expert opinion and were hampered by high variability and location-specific characteristics. Few cost studies reported disease-stage-specific costs (n = 3) or fully captured indirect costs. Utilities in three studies of MND patients used the EuroQol EQ-5D questionnaire or standard gamble, but included potentially unrepresentative cohorts and did not consider any health impacts on caregivers.

CONCLUSION

Economic evaluations in MND suffer from significant methodological issues such as a lack of data, uncertainty with the disease course and use of inappropriate modelling framework. Limitations may be addressed through the collection of detailed and representative data from large cohorts of patients.

Bias in Markov models of disease

We examine bias in Markov models of diseases, including both chronic and infectious diseases. We consider two common types of Markov disease models: ones where disease progression changes by severity of disease, and ones where progression of disease changes in time or by age. We find sufficient conditions for bias to exist in models with aggregated transition probabilities when compared to models with state/time dependent transition probabilities. We also find that when aggregating data to compute transition probabilities, bias increases with the degree of data aggregation. We illustrate by examining bias in Markov models of Hepatitis C, Alzheimer's disease, and lung cancer using medical data and find that the bias is significant depending on the method used to aggregate the data. A key implication is that by not incorporating state/time dependent transition probabilities, studies that use Markov models of diseases may be significantly overestimating or underestimating disease progression. This could potentially result in incorrect recommendations from cost-effectiveness studies and incorrect disease burden forecasts.

The costs of amyotrophic lateral sclerosis, according to type of care

Our objective was to estimate the economic burden of patients with amyotrophic lateral sclerosis (ALS) and to examine the effect of treatment in a multidisciplinary ALS treatment centre versus general care on costs and to describe differences in costs according to clinical characteristics. In a cross-sectional study 208 patients with ALS and their caregivers were interviewed and were asked to fill in a cost diary for six months. Patients were divided in groups according to type of treatment they received and according to clinical characteristics (site of onset, severity). The direct healthcare and non-healthcare costs were calculated according to Dutch guidelines for cost analysis in healthcare research, standardized for the year 2003. Ninety-eight patients were included when they had filled in the cost diary for at least three months and were affected for three years or less. Mean monthly costs were 1336 euros for the group receiving multidisciplinary care and 1271 euros for those receiving general care. This study shows that the costs of multidisciplinary ALS care were practically identical to the costs of general care. Earlier study showed that patients receiving multidisciplinary care had a better quality of life; therefore, the present study encourages the formation of multidisciplinary teams of professionals specialized in ALS care to further improve standards of care and QoL of patients suffering from ALS.

Health utility values associated with diabetic retinopathy

AIMS

Different estimates exist regarding the impact of diabetic retinopathy (DR) on health utility. A previously reported prospective observational study has reported much larger decrements in self-reported utility than generic utility data from the UK Prospective Diabetes Study and the Lipids in Diabetes Study. The present study was designed to estimate utility loss using multiple methods.

METHODS

Detailed health state descriptions reflecting declining DR (five different visual acuity levels), neuropathy and nephropathy were validated with patients and used to elicit utility values from people with DR, people with diabetes and members of the UK general public using standard gamble. In addition, a larger sample of people with retinopathy completed different health-related quality of life measures in an interview [EuroQoL (EQ-5D), Health State Utilities Index (HUI)-3, and National Eye Institute Visual Functioning Questionnaire-25].

RESULTS

The utility scores from the standard gamble interviews were not significantly different between the three groups. There was a decline in utility from 6/6 vision to counting fingers of -0.244. The utility data derived from the generic measures revealed an equivalent decline of -0.41 on both the EQ-5D single index and the HUI-3.

CONCLUSIONS

This study has re-examined the utility decrements associated with DR and has identified much larger declines in utility than previously reported. The study has also reported the utility values of patients with retinopathy as assessed by standard gamble. We believe that this may be the first study to report utility values for health states associated with vision loss which have been elicited from patients with vision loss.

Integrating preferences into health status assessment for amyotrophic lateral sclerosis: the ALS Utility Index

We developed a preference-based measure, the Amyotrophic Lateral Sclerosis Utility Index (ALSUI), allowing computation of US population-based utility weights for the wide range of health states observed among ALS patients. A multi-attribute utility approach was used. An ALS Health State Classification System was developed comprising the following attributes with different severity levels: Speech and Swallowing (A1); Eating, Dressing, and Bathing (A2); Leg Function (A3); and Respiratory Function (A4). An internet-based survey was administered to a random sample of the US population to assess preferences for ALS health states based on this system using visual analog scale (VAS) and standard gamble (SG) questions. Using the VAS and SG data from 1374 individuals in the general population, utility functions were computed that corresponded to each severity level within A1, A2, A3, and A4. ALSUI scores for a given patient are computed by inputting his corresponding utility functions into the following multiplicative formula: ALSUI score = 1.06 x (A1 x A2 x A3 x A4) - 0.06 on a scale where 0.0 reflects death and 1.0 reflects healthy. This study provides a useful tool for classifying ALS patients and determining a general public-based utility score for ALS health states.

The cost-effectiveness of early noninvasive ventilation for ALS patients

Background

Optimal timing of noninvasive positive pressure ventilation (NIPPV) initiation in patients with amyotrophic lateral sclerosis (ALS) is unknown, but NIPPV appears to benefit ALS patients who are symptomatic from pulmonary insufficiency. This has prompted research proposals of earlier NIPPV initiation in the ALS disease course in an attempt to further improve ALS patient quality of life and perhaps survival. We therefore used a cost-utility analysis to determine a priori what magnitude of health-related quality of life (HRQL) improvement early NIPPV initiation would need to achieve to be cost-effective in a future clinical trial.

Methods

Using a Markov decision analytic model we calculated the benefit in health-state utility that NIPPV initiated at ALS diagnosis must achieve to be cost-effective. The primary outcome was the percent utility gained through NIPPV in relation to two common willingness-to-pay thresholds: $50,000 and $100,000 per quality-adjusted life year (QALY).

Results

Our results indicate that if NIPPV begun at the time of diagnosis improves ALS patient HRQL as little as 13.5%, it would be a cost-effective treatment. Tolerance of NIPPV (assuming a 20% improvement in HRQL) would only need to exceed 18% in our model for treatment to remain cost-effective using a conservative willingness-to-pay threshold of $50,000 per QALY.

Conclusion

If early use of NIPPV in ALS patients is shown to improve HRQL in future studies, it is likely to be a cost-effective treatment. Clinical trials of NIPPV begun at the time of ALS diagnosis are therefore warranted from a cost-effectiveness standpoint.