Verteporfin photodynamic therapy for neovascular age-related ...

DOI: 10.3310/hta16060Health Technology Assessment 2012; Vol. 16: No. 673gain. The incremental cost per QALY was £170,000 over 2 years for the base case. Even if thegain from the intervention was extrapolated over 5 years, the incremental cost per QALY wasstill approximately £100,000, five times higher than the threshold that NICE uses to identifyinterventions that are ‘relatively cost-effective’. 15 The cost-effectiveness ratios reported in previousCEA of VPDT for nAMD have ranged from US$30,000 to US$250,000 (£20,000 to £166,667assuming an exchange rate of US$1.5 to the UK pound). 26,28 Unlike previous CEA of VPDTfor patients with predominantly classic CNV secondary to nAMD, we were able to include allappropriate costs and account for HRQoL associated with vision loss. This resulted in improvedpatient-centred estimates that showed that VPDT is unlikely to be cost-effective.There are three other features of our CEA that are relevant to future CEA of interventions fornAMD. Firstly, the study used data on the use of a treatment in routine practice rather than datacollected in accordance with a trial protocol. Despite the much lower treatment frequency, weobserved similar visual outcomes to those observed in the TAP trials. In the case of our CEA,it was more appropriate to use the lower treatment frequency observed in the VPDT cohortstudy, and previous CEAs that used treatment frequencies from the TAP trials overstated theincremental costs of the VPDT intervention compared with BSC. 19,26,77 The lesson for future CEAis that treatment intensities observed in licensing trials may overestimate the treatment intensityused in routine practice and, hence, overestimate the costs of treatment in the usual care setting.Second, previous CEAs either excluded costs associated with declining vision or estimatedthese costs based on expert opinion. 19,26,28,77–79 By contrast, by collecting patient-level data onHSS resource use and BCVA, our CEA was able to incorporate the cost of declining vision. Ourdata showed that the HSS costs for patients with nAMD were low (e.g. a mean of £320 for BSCgroup in year 1), and hence the reduction in these costs after VPDT was relatively small (£151over 2 years). The costs were lower than those reported by a recent observational study assessingthe economic burden of nAMD by self-reported use from 400 patients across five differentcountries 23 and from studies of Medicare costs based on claims data. 80,81 However, these studieswere based on aggregated costing approaches, which tend to overstate costs. The morbiditycosts observed in the VPDT cohort study relied entirely on patient recall and therefore mayhave under-represented the true cost, and also they may reflect the relatively poor availability oflow-vision services in the UK; previous studies have found a similarly low use of vision-relatedservices in the UK. 82,83 However, this low use of vision services has been reported in othercountries that have used patient-level data, which suggests that the current findings may be morewidely applicable. 24 The lesson for future CEA is that the source and robustness of data describingcosts associated with declining vision need to appraised with care.The third feature of our CEA that is relevant to future CEA concerns the importance of usingHRQoL measures based on preference weights from the general population rather than patientswith nAMD.A final issue for future CEAs which emerged from the VPDT study but which was notincorporated into our CEA was the relationship between BCVA and HRQoL. The regressionmodels which investigated this relationship found that the rate of change in HRQoL with varyingBCVA was not influenced by whether the better- or the worse-seeing eye was being treated.However, a key assumption in this and other CEA is that it is always the better-seeing eye thatis being treated, as the HRQoL gain is ‘credited’ for all treated eyes. Unless policy-makers rulethat worse-seeing or ‘first’ eyes should not be treated (an option considered but rejected byNICE during its deliberations prior to issuing its technology appraisal 6 ), the worse-seeing eyewill be treated in a proportion of patients (48% in the VPDT cohort study). Therefore, the CEAreported here (and other CEAs) has overstated the QALY gain and the cost-effectiveness of© Queen’s Printer and Controller of HMSO 2012. This work was produced by Reeves et al. under the terms of a commissioning contract issued by theSecretary of State for Health.