How lack of information hampers decision making in ophthalmology

Abstract

Introduction: Demonstration of cost-effectiveness is an established hurdle for new treatments and technologies. However, evidence synthesis, including simulation modelling, can be very difficult in the absence of good quality research that addresses pertinent questions, and people with rare conditions may have to forego the best available treatments. We illustrate this point with regard to the current choice between intravitreal ranibizumab, verteporfin photodynamic therapy (VPDT) or combinations of these (combination therapy) for polypoidal choroidal vasculopathy. Methods: We developed a Markov model to simulate equivalent cohorts of 65-year-old patients over a lifetime horizon. We obtained costs from the NHS national tariff, and utility values based on unilateral visual function deterioration. We carried out deterministic and probabilistic sensitivity analyses to investigate the sensitivity of the results to uncertainty in the model parameters. Results: Our model predicts that both VPDT and combination therapy offer cost savings but lower clinical efficacy over a lifetime horizon at δ81 165 and δ14 826 per quality-adjusted life year (QALY) respectively. VPDT monotherapy has a 99% chance of cost-effectiveness at a willingness to pay of δ30 000 per QALY gained. Combination therapy has a low (29%) probability of cost-effectiveness, however, this is heavily dependent on the modelled incidence of haemorrhagic adverse events. Conclusion: Based on the results of our model, VPDT might be commissioned according to a strict decision rule interpretation. The outcome regarding combination therapy is uncertain. These conclusions are dependent on the available evidence. There is considerable modelling and parameter uncertainty, which needs to be urgently addressed.