Rachel Houten’s journal round-up for 8th July 2019

Every Monday our authors provide a round-up of some of the most recently published peer reviewed articles from the field. We don’t cover everything, or even what’s most important – just a few papers that have interested the author. Visit our Resources page for links to more journals or follow the HealthEconBot. If you’d like to write one of our weekly journal round-ups, get in touch.

Adjusting for inflation and currency changes within health economic studies. Value in Health Published 13th June 2019

The purpose of the paper is to highlight the need for transparency in the reporting of methods of currency conversions and adjustments to costs to take inflation into account, in economic evaluations. It chimes with other recent literature which is less prescriptive in terms of providing methods guidelines and more about advocating the “tell us what you did and why” approach. It reminds me of my very first science lesson in high school where we were eager to get our hands on the experiments yet the teacher (met by much eye-rolling) insisted on the importance of describing the methods of any ‘study’. With space at a premium in academic writing, I know, and I’m likely guilty of, some transparency in assumptions being culled, but papers such as this highlight their necessity.

The authors discuss which inflation measure to base the adjustments on, whether to convert local currencies to US or International dollars, three methods of adjusting for inflation, and what to do when costs from other settings are part of the analysis. With a focus on low- and middle-income countries, and using a hypothetical example, the authors demonstrate that employing three different methods of adjusting for inflation can result in a large range in the final estimates.

The authors acknowledge that it is not a one-size-fits-all approach but favour a ‘mixed approach’ where micro-costing is possible and items can be classified as tradable and non-tradable, as they say this is likely to produce the most accurate estimates. However, a study reliant on previously published costing information would need to follow an alternative approach, of which there are two others detailed in the paper.

In terms of working with data from low- and middle-income countries, I can’t say it is my forté. However, the paper summarises the pros and cons of each of their proposed approaches in a straightforward way. The authors include a table that I think would provide an excellent reference point for anyone considering the best approach for their specific set of circumstances.

An updated systematic review of studies mapping (or cross‑walking) measures of health‑related quality of life to generic preference‑based measures to generate utility value. Applied Health Economics and Health Policy [PubMed] [RePEc] Published 3rd April 2019

This is an update of a review of studies published before 2007, which found 30 studies mapping to generic preference-based measures. This latest paper cites 180 included studies with a total of 233 mapping functions reported. The majority of the mapping functions were to the EQ-5D (147 mapping functions) with the second largest group mapping to the SF-6D (45 mapping functions).

Along with an increase in volume of mapping studies since the last review, there has been a marked increase in the different types of regression methods used, which signals a greater consideration of the distribution of the underlying utility data. Reporting on how well the mapping algorithms predict utility in different sub-groups has also increased.

The authors highlight that although mapping can fill an evidence gap, the uncertainty in the estimates is greater than directly measuring health-related quality of life in prospective studies. The authors signpost to ISPOR guidelines for the reporting of mapping studies and emphasise the need to include measurements of error as well as a plot of predicted versus observed values, to enable the user to understand and incorporate the accuracy of the mapping in their economic evaluations.

As stated by the authors, the results of this review provides a useful resource in terms of a catalogue of mapping studies, however it lacks any quality assessment of the studies (also made clear by the authors), so the choice of which mapping algorithm to use is still ours, and takes some thought.  The supplementary Excel file is a great resource to aid the choice as it includes some information about the populations used in the mapping studies alongside the methods, but more studies comparing mapping functions with the same aim against each other would be welcomed.

Investigating the relationship between formal and informal care: an application using panel data for people living together. Health Economics [PubMed] Published 7th June 2019

This paper adds to the literature on informal care by considering co-resident informal care in a UK setting using data from the British Household Panel Survey (BHPS). There has been an increase in the proportion of people receiving non-state provided care in recent years in the UK, and the BHPS also enables the impact of informal care on the use of each of these types of formal care to be explored.

The authors used an instrument for informal care to try to prevent bias due to correlations with other variables such as health. The instrument used for the availability of informal care was the number of adult daughters as it was found to be the most predictive (oh dear, I’ve two sons!). The authors then estimated the impact of informal care on home help, health visitor use, GP visits, and hospital stays.

In this study, informal care was a substitute for both state and non-state home help (with the impact greater for state home help) and complimentary to health visitor use, GP visits, and hospital stays. The authors suggest this may be due to the tasks completed by these different types of service providers and how household tasks are more likely to be undertaken by informal care givers than those more medical in nature. The fact this study considers co-residential care from any household member may explain the stronger substitution effect in this study compared to previous studies looking at informal caregivers living elsewhere as it could be assumed the caregiver residing with the care recipient is more able to provide care.

I find the make-up of households and how that impacts on the need for healthcare resources really interesting, especially as it is generally considered that informal care and the work of charities bolsters the NHS. The results of this study suggest that increases in informal care could generate savings in terms of the need for home help, but an increase in formal care resource use. The reasons for the complimentary relationship between informal care and health visitor, GP, and hospital visits need further exploration.

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Paul Mitchell’s journal round-up for 6th November 2017

Every Monday our authors provide a round-up of some of the most recently published peer reviewed articles from the field. We don’t cover everything, or even what’s most important – just a few papers that have interested the author. Visit our Resources page for links to more journals or follow the HealthEconBot. If you’d like to write one of our weekly journal round-ups, get in touch.

A longitudinal study to assess the frequency and cost of antivascular endothelial therapy, and inequalities in access, in England between 2005 and 2015. BMJ Open [PubMed] Published 22nd October 2017

I am breaking one of my unwritten rules in a journal paper round-up by talking about colleagues’ work, but I feel it is too important not to provide a summary for a number of reasons. The study highlights the problems faced by regional healthcare purchasers in England when implementing national guideline recommendations on the cost-effectiveness of new treatments. The paper focuses on anti-vascular endothelial growth factor (anti-VEGF) medicines in particular, with two drugs, ranibizumab and aflibercept, offered to patients with a range of eye conditions, costing £550-800 per injection. Another drug, bevacizumab, that is closely related to ranibizumab and performs similarly in trials, could be provided at a fraction of the cost (£50-100 per injection), but it is currently unlicensed for eye conditions in the UK. This study investigates how the regional areas in England have coped with trying to provide the recommended drugs using administrative data from Hospital Episode Statistics in England between 2005-2015 by tracking their use since they have been recommended for a number of different eye conditions over the past decade. In 2014/15 the cost of these two new drugs for treating eye conditions alone was estimated at £447 million nationally. The distribution of where these drugs are provided is not equal, varying widely across regions after controlling for socio-demographics, suggesting an inequality of access associated with the introduction of these high-cost drugs over the past decade at a time of relatively low growth in national health spending. Although there are limitations associated with using data not intended for research purposes, the study shows how the most can be made from data routinely collected for non-research purposes. On a public policy level, it raises questions over the provision of such high-cost drugs, for which the authors state the NHS are currently paying more for than US insurers. Although it is important to be careful when comparing to unlicensed drugs, the authors point to clear evidence in the paper as to why their comparison is a reasonable one in this scenario, with a large opportunity cost associated with not including this option in national guidelines. If national recommendations continue to insist that such drugs be provided, clearer guidance is also required on how to disinvest from existing services at a regional level to reduce further examples of inequality in access in the future.

In search of a common currency: a comparison of seven EQ-5D-5L value sets. Health Economics [PubMed] Published 24th October 2017

For those of us out there who like a good valuation study, you will need to set yourself aside a good piece of time to work your way through this one. The new EQ-5D-5L measure of health status, with a primary purpose of generating quality-adjusted life years (QALYs) for economic evaluations, is now starting to have valuation studies emerging from different countries, whereby the relative importance of each of the measure dimensions and levels are quantified based on general population preferences. This study offers the first comparison of value sets across seven countries: 3 Western European (England, Netherlands, Spain), 1 North American (Canada), 1 South American (Uruguay), and two East Asian (Japan and South Korea). The authors in this paper aim to describe methodological differences between the seven value sets, compare the relative importance of dimensions, level decrements and scale length (i.e. quality/quantity trade-offs for QALYs), as well as developing a common (Western) currency across four of the value sets. In brief summary, there does appear to be similar trends across the three Western European countries: level decrements from levels 3 to 4 have the largest value, followed by levels 1 to 2. There is also a pattern in these three countries’ dimensions, whereby the two “symptom” dimensions (i.e. pain/discomfort, anxiety/depression) have equal importance to the other three “functioning” dimensions (i.e. mobility, self-care and usual activities). There are also clear differences with the other four value sets. Canada, although it also has the highest level decrements between levels 3 and 4 (49%), unusually has equal decrements for the remainder (17% x 3). For the other three countries, greater weight is attached to the three functioning dimensions relative to the two symptom dimensions. Although South Korea also has the greatest level decrements between level 3 and 4, it was greatest between level 4 and level 5 in Uruguay and levels 1 and 2 in Japan. Although the authors give a number of plausible reasons as to why these differences may occur, less justification is given in the choice of the four value sets they offer as a common currency, beyond the need to have a value set for countries that do not have one already. The most in-common value sets were the three Western European countries, so a Western European value set may have been more appropriate if the criterion was to have comparable values across countries. If the aim was really for a more international common currency, there are issues with the exclusion of non-Western countries’ value sets from their common currency version. Surely differences across cultures should be reflected in a common currency if they are apparent in different cultures and settings. A common currency should also have a better spread of regions geographically, with no country from Africa, the Middle East, Central and South Asia represented in this study, as well as no lower- and middle-income countries. Though this final criticism is out of the control of the authors based on current data availability.

Quantifying the relationship between capability and health in older people: can’t map, won’t map. Medical Decision Making [PubMed] Published 23rd October 2017

The EQ-5D is one of many ways quality of life can be measured within economic evaluations. A more recent way based on Amartya Sen’s capability approach has attempted to develop outcome measures that move beyond health-related aspects of quality of life captured by EQ-5D and similar measures used in the generation of QALYs. This study examines the relationship between the EQ-5D and the ICECAP-O capability measure in three different patient populations included in the Medical Crises in Older People programme in England. The authors propose a reasonable hypothesis that health could be considered a conversion factor for a person’s broader capability set, and so it is plausible to test how well the EQ-5D-3L dimension values and overall score can map onto the ICECAP-O overall score. Through numerous regressions performed, the strongest relationship between the two measures in this sample was an R-squared of 0.35. Interestingly, the dimensions on the EQ-5D that had a significant relationship with the ICECAP-O score were a mix of dimensions with a focus on functioning (i.e. self-care, usual activities) and symptoms (anxiety/depression), so overall capability on ICECAP-O appears to be related, at least to a small degree, to both health components of EQ-5D discussed in this round-up’s previous paper. The authors suggest it provides further evidence of the complementary data provided by EQ-5D and ICECAP-O, but the causal relationship, as the authors suggest, between both measures remains under-researched. Longitudinal data analysis would provide a more definitive answer to the question of how much interaction there is between these two measures and their dimensions as health and capability changes over time in response to different treatments and care provision.

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Alastair Canaway’s journal round-up for 28th August 2017

Every Monday our authors provide a round-up of some of the most recently published peer reviewed articles from the field. We don’t cover everything, or even what’s most important – just a few papers that have interested the author. Visit our Resources page for links to more journals or follow the HealthEconBot. If you’d like to write one of our weekly journal round-ups, get in touch.

Valuing health-related quality of life: an EQ-5D-5L value set for England. Health Economics [PubMed] Published 22nd August 2017

With much anticipation, the new EQ-5D-5L value set was officially published. For over 18 months we’ve had access to values via the OHE’s discussion paper but the formal peer-reviewed paper has (I imagine) been in publication purgatory. This paper presents the results of the value-set for the new (ish) EQ-5D-5L measure. The study used the internationally agreed hybrid model combining TTO and DCE data to generate the values for the 3125 health states. It’s worth noting that the official values are marginally different to those in the discussion paper, although in practice this is likely to have little impact on results. Important results of the new value set include fewer health states worse than death (5.1% vs over 33%), and a higher minimum value (-0.285 vs -0.594). I’d always been a bit suspect of the values for worse than death states for the 3L measure, so this if anything is encouraging. This does, however, have important implications, primarily for interventions seeking to improve those in the worst health, where potential gains may be reduced. Many of us are actively using the EQ-5D-5L within trials and have been eagerly awaiting this value set. Perhaps naively, I always anticipated that with more levels and an improved algorithm it would naturally supersede the 3L and the outdated 3L value set upon publication. Unfortunately, to mark the release of the new value set, NICE released a ‘position statement’ [PDF] regarding the choice of measure and value sets for the NICE reference case. NICE specifies that i) the 5L value set is not recommended for use, ii) the EQ-5D-3L with the original UK TTO value set is recommended and if both measures are included then the 3L should be preferred, iii) if the 5L measure is included, then scores should be mapped to the EQ-5D-3L using the van Hout et al algorithm, iv) NICE supports the use of the EQ-5D-5L generally to collect data on quality of life, and v) NICE will review this decision in August 2018 in light of future evidence. So, unfortunately, for the next year at least, we will be either sticking to the original 3L measure or mapping from the 5L. I suspect NICE is buying some time as transitioning to the 5L is going to raise lots of interesting issues e.g. if a measure is cost-effective according to the 3L, but not the 5L, or vice-versa, and comparability of 5L results to old 3L results. Interesting times lie ahead. As a final note, it’s worth reading the OHE blog post outlining the position statement and OHE’s plans to satisfy NICE.

Long-term QALY-weights among spouses of dependent and independent midlife stroke survivors. Quality of Life Research [PubMed] Published 29th June 2017

For many years, spillover impacts were largely being ignored within economic evaluation. There is increased interest in capturing wider impacts, indeed, the NICE reference case recommends including carer impacts where relevant, whilst the US Panel on Cost-Effectiveness in Health and Medicine now advocates the inclusion of other affected parties. This study sought to examine whether the dependency of midlife stroke survivors impacted on their spouses’ HRQL as measured using the SF-6D. An OLS approach was used whilst controlling for covariates (age, sex and education, amongst others). Spouses of dependent stroke survivors had a lower utility (0.69) than those whose spouses were independent (0.77). This has interesting implications for economic evaluation. For example, if a treatment were to prevent dependence, then there could potentially be large QALY gains to spouses. Spillover impacts are clearly important. If we are to broaden the evaluative scope as suggested by NICE and the US Panel to include spillover impacts, then work is vital in terms of identifying relevant contexts, measuring spillover impacts, and understanding the implications of spillover impacts within economic evaluation. This remains an important area for future research.

Conducting a discrete choice experiment study following recommendations for good research practices: an application for eliciting patient preferences for diabetes treatments. Value in Health Published 7th August 2017

To finish this week’s round-up I thought it’d be helpful to signpost this article on conducting DCEs, which I feel may be helpful for researchers embarking on their first DCE. The article hasn’t done anything particularly radical or made ground-breaking discoveries. What it does however do is give you a practical guide to walk you through each step of the DCE process following the ISPOR guidelines/checklist. Furthermore, it expands upon the ISPOR checklist to provide researchers with a further resource to consider when conducting DCEs. The case study used relates to measuring patient preferences for type 2 diabetes mellitus medications. For every item on the ISPOR checklist, it explains how they made the choices that they did, and what influenced them. The paper goes through the entire process from identifying the research question all the way through to presenting results and discussion (for those interested in diabetes – it turns out people have a preference for immediate consequences and have a high discount rate for future benefits). For people who are keen to conduct a DCE and find a worked example easier to follow, this paper alongside the ISPOR guidelines is definitely one to add to your reference manager.

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