The value of any healthcare intervention is determined by characterizing the financial costs of introducing the treatment and by understanding the overall deficits and benefits of treatment. These factors are then set against the interventions for which they are substituting to determine what is termed the incremental cost-effectiveness ratio (or ICER). The ICER is often a generic metric of cost–benefit that distils what is known about the health intervention into a single value that can be used together with other information to support a decision about market access of the healthcare intervention. Benefit – the denominator in an ICER – can be disease specific. Importantly, when the measure of outcome is health-related utility, this is termed the cost per quality adjusted life year, or QALY. This generic metric can be used to compare very differing health interventions because the method of valuing health benefit is common to all such evaluations.
The value estimate – the incremental cost per QALY – of any product will differ by country, by differing healthcare systems and even over time, and there will be uncertainty about the ICER value in any evaluation because of the imprecision of the data used in any economic evaluation, and other factors. Determination of the ICER is typically carried out through the medium of a mathematical model of the disease and intervention, either in a general healthcare setting, or within a trial or study. The most favorable intervention is termed in health economic parlance as being “dominant”. That means that the comparative intervention of interest is both cheaper financially and has greater health benefit. Failing dominance, the ICER can then be used to provide a measure of the financial cost to a healthcare system of buying a unit of health. The individual system then places a threshold that details the willingness to pay for that system to purchase a unit of health benefit. This threshold is important since budgets are finite, and a decision to spend funds on one intervention means that there are no funds to purchase another. In economic parlance, there is an opportunity cost.
In this series of studies evaluating the clinical changes and the resource use implications of Iluvien 190 μg intravitreal implant in routine clinical practice in Current Medical Research and OpinionCitation1–4, the authors provide quite detailed data from their real-life, observational study – the ICE-UK study. This provides data on both the clinical outcome of treatment, and the financial resources used and the related costs of treatment, both prior to and post implantation. Whilst itself this is not a full economic evaluation, this data provides much of the underlying information necessary to produce an ICER. With the costs produced here, only estimates of QALY gains are required to produce a generic ICER and these could be estimated from their findings relating to visual acuityCitation5.
Being an observational study, there are inherent limitations. A lack of randomization is generally considered to be a serious problem as results can be confounded. However, the authors have addressed this limitation to some extent by reporting the visual acuity in the non-treated eye. This makes sense, since both eyes are exposed to the diabetes-related environment that leads to the complications of chronic hyperglycemia. However, there remains a potential bias due to the rules by which a doctor chooses to treat one eye over another, although NICE has established some of these rules for the UKCitation6. The other limitation of this study is that it reports the observed costs and eye-related clinical outcomes to 12 months, along with useful data from the prior 12 months. The intraocular implant in question releases its constituent steroidal drug for three years. Thus, the acquisition cost of the product is loaded at the beginning of treatment, and the potential benefits then yielded over the following three-year period. The data as presented – whilst already looking promising – should result in an improving estimated value for money of the implant over this extended time-period, until the steroid from the implant is exhausted. I believe that later data analyses are planned.
It should also be recognized that observational studies also have their advantages. Trial results can be biased due to the presence of protocol driven costs and outcomes, for example, intensive follow-up mandated by the study protocol can artificially equalize costs and outcomes between study arms, since all patients receive “Rolls Royce care”. Likewise, in pursuit of clearer results, trial designers frequently adopt restrictive eligibility criteria in order to remove factors that could complicate the interpretation of the findings, for example, previous treatment or comorbidities. The studies presented here are based on patient samples that are not influenced by study protocols or overly restrictive eligibility criteria.
Data from the ICE-UK study appears to demonstrate that the intraocular implant either prevents further deterioration in any treated eye or, better, it improves visual acuity. This seems to depend on the degree of poor vision at implantation. Regarding the impact on treatment costs, there was a marked reduction in the costs of other eye-related therapies following implant, and this relative saving was ongoing at 12 months. It is possible that, once fully evaluated, the fluocinolone acetonide intravitreal implant may represent good value for money.
Transparency
Declaration of funding
This editorial is part of a series of articles supported by Alimera Sciences, the manufacturer of the Iluvien 190 µg intravitreal implant.
Declaration of financial/other relationships
S.D. has disclosed that he has no significant relationships with or financial interests in any commercial companies related to this study or article.
CMRO peer reviewers on this manuscript have received an honorarium from CMRO for their review work, but have no relevant financial or other relationships to disclose.
References
- Holden SE, Currie CJ, Owens DR. Evaluation of the clinical effectiveness in routine practice of fluocinolone acetonide intravitreal 190 µg implant in people with diabetic macular edema. Curr Med Res Opin 2017;33(Suppl):5--17
- Currie CJ, Holden SE, Berni E, Owens DR. Evaluation of the clinical effectiveness of fluocinolone acetonide 190 µg intravitreal implant in diabetic macular edema: a comparison between study and fellow eyes. Curr Med Res Opin 2017;33(Suppl):19--31
- Currie CJ, Holden SE, Owens DR. Change in retinal thickness following treatment with the intravitreal implant of fluocinolone acetonide 190 µg for diabetic macular edema. Curr Med Res Opin 2017;33(Suppl):33--43
- Holden SE, Currie CJ, Owens DR. Health economic evaluation of fluocinolone acetonide 190 µg implant in people with diabetic macular edema. Curr Med Res Opin 2017;33(Suppl):45--52
- Sharma S, Brown GC, Brown MM, et al. Converting visual acuity to utilities. Can J Ophthalmol 2000;35:267-72
- Fluocinolone acetonide intravitreal implant for treating chronic diabetic macular oedema after an inadequate response to prior therapy. Available at: https://www.nice.org.uk/Guidance/TA301 [Last accessed 26 April 2017]