Carer and family spillovers in economic evaluation

It is increasingly recognised that costs and outcomes falling on carers and others close to the patient should be considered in economic evaluation. This workshop will cover a range of techniques that have been developed and applied over the last 20 years. The day will comprise lectures and practical sessions, and an opportunity for participants to discuss their research challenges with the workshop leaders.

Workshop leaders:
Hareth Al-Janabi, Senior Lecturer in Health Economics, University of Birmingham
Werner Brouwer, Professor of Health Economics, Erasmus University, Rotterdam

Please contact Hareth Al-Janabi (h.aljanabi@bham.ac.uk) to register and/or ask any questions about the workshop.

Chris Sampson’s journal round-up for 15th October 2018

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.

Reliability and validity of the contingent valuation method for estimating willingness to pay: a case of in vitro fertilisation. Applied Health Economics and Health Policy [PubMed] Published 13th October 2018

In vitro fertilisation (IVF) is a challenge for standard models of valuation in health economics. Mostly, that’s because, despite it falling within the scope of health care, and despite infertility being a health problem, many of the benefits of IVF can’t be considered health-specific. QALYs can’t really do the job, so there’s arguably a role for cost-benefit analysis, and for using stated preference methods to determine the value of IVF. This study adds to an existing literature studying willingness to pay for IVF, but differs in that it tries to identify willingness to pay (WTP) from the general population. This study is set in Australia, where IVF is part-funded by universal health insurance, so asking the public is arguably the right thing to do.

Three contingent valuation surveys were conducted online with 1,870 people from the general public. The first survey used a starting point bid of $10,000, and then, 10 months later, two more surveys were conducted with starting point bids of $4,000 and $10,000. Each included questions for a 10%, 20%, and 50% success rate. Respondents were asked to adopt an ex-post perspective, assuming that they were infertile and could conceive by IVF. Individuals could respond to starting bids with ‘yes’, ‘no’, ‘not sure’, or ‘I am not willing to pay anything’. WTP for one IVF cycle with a 20% success rate ranged from $6,353 in the $4,000 survey to $11,750 in the first $10,000 survey. WTP for a year of treatment ranged from $18,433 to $28,117. The method was reliable insofar as there were no differences between the first and second $10,000 surveys. WTP values corresponded to the probability of success, providing support for the internal construct validity of the survey. However, the big difference between values derived using the alternative starting point bids indicates a strong anchoring bias. The authors also tested the external criterion validity by comparing the number of respondents willing to pay more than $4,000 for a cycle with a 20% success rate (roughly equivalent to the out of pocket cost in Australia) with the number of people who actually choose to pay for IVF in Australia. Around 63% of respondents were willing to pay at that price, which is close to the estimated 60% in Australia.

This study provides some support for the use of contingent valuation methods in the context of IVF, and for its use in general population samples. But the anchoring effect is worrying and justifies further research to identify appropriate methods to counteract this bias. The exclusion of the “not sure” and “I will not pay anything” responses from the analysis – as ‘non-demanders’ – arguably undermines the ‘societal valuation’ aspect of the estimates.

Pharmaceutical expenditure and gross domestic product: evidence of simultaneous effects using a two‐step instrumental variables strategy. Health Economics [PubMed] Published 10th October 2018

The question of how governments determine spending on medicines is pertinent in the UK right now, as the Pharmaceutical Price Regulation Scheme approaches its renewal date. The current agreement includes a cap on pharmaceutical expenditure. It should go without saying that GDP ought to have some influence on how much public spending is dedicated to medicines. But, when medicines expenditure might also influence GDP, the actual relationship is difficult to estimate. In this paper, the authors seek to identify both effects: the income elasticity of government spending on pharmaceuticals and the effect of that spending on income.

The authors use a variety of data sources from the World Health Organization, World Bank, and International Monetary Fund to construct an unbalanced panel for 136 countries from 1995 to 2006. To get around the challenge of two-way causality, the authors implement a two-step instrumental variable approach. In the first step of the procedure, a model estimates the impact of GDP per capita on government spending on pharmaceuticals. International tourist receipts are used as an instrument that is expected to correlate strongly with GDP per capita, but which is expected to be unrelated to medicines expenditure (except through its correlation with GDP). The model attempts to control for health care expenditure, life expectancy, and other important country-specific variables. In the second step, a reverse causality model is used to assess the impact of pharmaceutical expenditure on GDP per capita, with pharmaceutical expenditure adjusted to partial-out the response to GDP estimated in the first step.

The headline average results are that GDP increases pharmaceutical expenditure and that pharmaceutical expenditure reduces GDP. A 1% increase in GDP per capita increases public pharmaceutical expenditure per capita by 1.4%, suggesting that pharmaceuticals are a luxury good. A 1% increase in public pharmaceutical expenditure is associated with a 0.09% decrease in GDP per capita. But the results are more nuanced than that. The authors outline various sources of heterogeneity. The positive effect of GDP on pharmaceutical expenditure only holds for high-income countries and the negative effect of pharmaceutical expenditure on GDP only holds for low-income countries. Quantile regressions show that income elasticity decreases for higher quantiles of expenditure. GDP only influences pharmaceutical spending in countries classified as ‘free’ on the index of Economic Freedom of the World, and pharmaceutical expenditure only has a negative impact on GDP in countries that are ‘not free’.

I’ve never come across this kind of two-step approach before, so I’m still trying to get my head around whether the methods and the data are adequate. But a series of robustness checks provide some reassurance. In particular, an analysis of intertemporal effects using lagged GDP and lagged pharmaceutical expenditure demonstrates the robustness of the main findings. Arguably, the findings of this study are more important for policymaking in low- and middle-income countries, where pharmaceutical expenditures might have important consequences for GDP. In high-income (and ‘free’) economies that spend a lot on medicines, like the UK, there is probably less at stake. This could be because of effective price regulation and monitoring, and better adherence, ensuring that pharmaceutical expenditure is not wasteful.

Parental health spillover in cost-effectiveness analysis: evidence from self-harming adolescents in England. PharmacoEconomics [PubMed] [RePEc] Published 8th October 2018

Any intervention has the potential for spillover effects, whereby people other than the recipient of care are positively or negatively affected by the consequences of the intervention. Where a child is the recipient of care, it stands to reason that any intervention could affect the well-being of the parents and that these impacts should be considered in economic evaluation. But how should parental spillovers be incorporated? Are parental utilities additive to that of the child patient? Or should a multiplier effect be used with reference to the effect of an intervention on the child’s utility?

The study reports on a trial-based economic evaluation of family therapy for self-harming adolescents aged 11-17. Data collection included EQ-5D-3L for the adolescents and HUI2 for the main caregiver (86% mothers) at baseline, 6-month follow-up, and 12-month follow-up, collected from 731 patient-parent pairs. The authors outline six alternative methods for including parental health spillovers: i) relative health spillover, ii) relative health spillover per treatment arm, iii) absolute health spillover, iv) absolute global health spillover per treatment arm, v) additive accrued health benefits, and vi) household equivalence scales. These differ according to whether parental utility is counted as depending on adolescent’s utility, treatment allocation, the primary outcome of the study, or some combination thereof. But the authors’ primary focus (and the main contribution of this study) is the equivalence scale option. This involves adding together the spillover effects for other members of the household and using alternative weightings depending on the importance of parental utility compared with adolescent utility.

Using Tobit models, controlling for a variety of factors, the authors demonstrate that parental utility is associated with adolescent utility. Then, economic evaluations are conducted using each of the alternative spillover accounting methods. The base case of including only adolescents’ utility delivers an ICER of around £40,453. Employing the alternative methods gives quite different results, with the intervention dominated in two of the cases and an ICER below £30,000 per QALY in others. For the equivalence scale approach, the authors employ several elasticities for spillover utility, ranging from 0 (where parental utility is of equivalent value to adolescent utility and therefore additive) to 1 (where the average health spillover per household member is estimated for each patient). The ICER estimates using the equivalence scale approach ranged from £27,166 to £32,504. Higher elasticity implied lower cumulated QALYs.

The paper’s contribution is methodological, and I wouldn’t read too much into the magnitude of the results. For starters, the use of HUI2 (a measure for children) in adults and the use of EQ-5D-3L (a measure for adults) in the children is somewhat confusing. The authors argue that health gains should only be aggregated at the household level if the QALY gain for the patient is greater or equal to zero, because the purpose of treatment is to benefit the adolescents, not the parents. And they argue in favour of using an equivalence scale approach. By requiring an explicit judgement to set the elasticity within the estimation, the method provides a useful and transparent approach to including parental spillovers.

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Meeting round-up: Health Economists’ Study Group (HESG) Winter 2018

Last week’s biannual intellectual knees-up for UK health economists took place at City, University of London. We’ve written before about HESG, but if you need a reminder of the format you can read Lucy Abel’s blog post on the subject. This was the first HESG I’ve been to in a while that took place in an actual university building.

The conference kicked off for me with my colleague Grace Hampson‘s first ever HESG discussion. It was an excellent discussion of Toby Watt‘s paper on the impact of price promotions for cola, in terms of quantities purchased (they increase) and – by extension – sugar consumption. It was a nice paper with a clear theoretical framework and empirical strategy, which generated a busy discussion. Nutrition is a subject that I haven’t seen represented much at past HESG meetings, but there were several on the schedule this time around with other papers by Jonathan James and Ben Gershlick. I expect it’s something we’ll see becoming more prevalent as policymaking becomes more insistent.

The second and third sessions I attended were on the relationship between health and social care, which is a pressing matter in the UK, particular with regard to achieving integrated care. Ben Zaranko‘s paper considered substitution effects arising from changes in the relative budgets of health and social care. Jonathan Stokes and colleagues attempted to identify whether the Better Care Fund has achieved its goal of reducing secondary care use. That paper got a blazing discussion from Andrew Street that triggered an insightful discussion in the room.

A recurring theme in many sessions was the challenge of communicating with local decision-makers, and the apparent difficulty in working without a reference case to fall back on (such as that of NICE). This is something that I have heard regularly discussed at least since the Winter 2016 meeting in Manchester. At City, this was most clearly discussed in Emma Frew‘s paper describing the researchers’ experiences working with local government. Qualitative research has clearly broken through at HESG, including Emma’s paper and a study by Hareth Al-Janabi on the subject of treatment spillovers on family carers.

I also saw a few papers that related primarily to matters of research conduct and publishing. Charitini Stavropoulou‘s paper explored whether highly-cited researchers are more likely to receive public funding, while the paper I chaired by Anum Shaikh explored the potential for recycling cost-effectiveness models. The latter was a joy for me, with much discussion of model registries!

There were plenty of papers that satisfied my own particular research interests. Right up my research street was Mauro Laudicella‘s paper, which used real-world data to assess the cost savings associated with redirecting cancer diagnoses to GP referral rather than emergency presentation. I wasn’t quite as optimistic about the potential savings, with the standard worries about lead time bias and selection effects. But it was a great paper nonetheless. Also using real-world evidence was Ewan Gray‘s study, which supported the provision of adjuvant chemotherapy for early stage breast cancer but delivered some perplexing findings about patient-GP decision-making. Ewan’s paper explored technical methodological challenges, though the prize for the most intellectually challenging paper undoubtedly goes to Manuel Gomes, who continued his crusade to make health economists better at dealing with missing data – this time for the case of quality of life data. Milad Karimi‘s paper asked whether preferences over health states are informed. This is the kind of work I enjoy thinking about – whether measures like the EQ-5D capture what really matters and how we might do better.

As usual, many delegates worked hard and played hard. I took a beating from the schedule at this HESG, with my discussion taking place during the first session after the conference dinner (where we walked in the footsteps of the Spice Girls) and my chairing responsibilities falling on the last session of the last day. But in both cases, the audience was impressive.

I’ll leave the final thought for the blog post with Peter Smith’s plenary, which considered the role of health economists in a post-truth world. Happily, for me, Peter’s ideas chimed with my own view that we ought to be taking our message to the man on the Clapham omnibus and supporting public debate. Perhaps our focus on (national) policymakers is too strong. If not explicit, this was a theme that could be seen throughout the meeting, whether it be around broader engagement with stakeholders, recognising local decision-making processes, or harnessing the value of storytelling through qualitative research. HESG members are STRETCHing the truth.

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