Evaluation of photodynamic ther-apy for the treatment of exudative age-related macular degenerati on (ARMD) with subfoveal neovascularization

Année de publication: 2005

OBJECTIVES:

Over the past few decades, most industrialized countries have experienced an increase in their elderly populations. This inversion of the age pyramid is leading to an increased incidence of many diseases, including age-related macular degeneration (ARMD). ARMD is characterized by degenerative lesions in the macular region of the retina resulting in a gradual decrease in vision that can lead to a loss of central vision. In fact, this disease is the leading cause of blindness in Western countries. Its prevalence is approximately 0.2% in people aged 55 to 64 and climbs to more than 13% in the over-85 population. Based on epidemiological data, the number of affected individuals in Québec can be estimated at approximately 37,200. ARMD has been divided into three histopa-thologic forms: an early form, also known as age-related maculopathy (ARM) or pre-ARMD (it should be noted that the early form is not included in the prevalence and inci-dence data provided in this report), and two advanced or progressive forms, called atro-phic and neovascular (or exudative) forms. At the present time, only the neovascular form is treatable. It accounts for about 47% of the cases of advanced ARMD, which, in Quebec, number close to 16,000. This disease therefore generates significant social costs, hence the need for effective therapeutic modalities to treat it. It was in this context that ophthalmologists representing the New Technologies Axis of the Vision Network, which is sponsored by the Fonds de la recherche en santé du Québec (FRSQ), asked the Agence d'évaluation des technologies et des modes d'intervention en santé (AETMIS) to assess the efficacy of photodynamic therapy (PDT) with verteporfin photosensitizer for the treatment of ARMD. This report also looks at the costs associated with this therapeutic modality and examines, on an exploratory basis, the organization of the care and services involved.

METHODOLOGY:

A literature search was conducted in the Pub-Med, Current Content Search and Cochrane Library databases by combining the terms macular degeneration, photodynamic therapy and verteporfin (Visudyne®); Amsler grid; an-tioxidant; vitamin; risk factors; side effects and fluorescein angiography for the period from 1975 to June 2004. We also used reports from several health technology assessment agencies that have examined PDT, abstracts of papers presented at international scientific confer-ences, a number of Web sites, and interviews with experts in ophthalmology and visual rehabilitation. The decision tree for the economic analysis was designed for the purpose of predicting the costs and effects of PDT in individuals with ARMD. The population selected for this Markov-type model includes all Quebecers who were over the age of 55 in 2001 (1,730,000). The incidence data for the disease are applied to this cohort.

Two options are compared in the model:

a treatment option and a no-treatment option. To include all the possible treatment scenarios, the time horizon in this model was set at eight years, and the outcomes used are the loss and non-loss of three lines of vision. It will be noted that visual rehabilitation costs are included in both options on the basis of the patient's visual acuity. The exploratory study of the organization of the care and services provided to ARMD pa-tients was conducted in the summer 2002 using a qualitative approach based on semi-structured telephone interviews with eye specialists at all of the university and com-munity hospitals and at certain private clinics in Québec that offer PDT, and with reception-ists and nurses who work at these facilities.

CONCLUSION:

From the evidence accumulated on photody-namic therapy with verteporfin photosensi-tizer we can conclude that this technology is effective in slowing the progression of subfo-veal neovascular ARMD with predominantly classic neovascularization or pure occult neo-vascularization. Further-more, the estimated budget impact for a Québec cohort is accept-able if the improvement in quality of life is taken into account. However, a major reor-ganization of services and ocular health care should be considered in the near future to permit the optimal implementation of this technology, to reduce waiting times for this treatment and to deal with the demand that will be increasing in the coming years. Furthermore, measures aimed at promoting the early detection of ARMD in the popula-tion, both at the individual and primary -care levels, could reduce the risk of severe, irre-versible vision loss and thus reduce the social costs of this disease.

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