Original Title: Manejo terapéutico de la Retinosis Pigmentaria

Authors' objectives: The main objective of this study is to assess the effectiveness and safety of the different therapies available to treat patients with RP as well as reporting on the current state of research leading to new therapies.

Authors' results and conclusions: RESULTS: The search yielded 2049 initial references and 40 studies were finally eligible for inclusion. Of them, ten are RCTs. Evidence from RCT are all for pharmacological or supplementation treatments. Overall, studies were of small sample sizes, no controlled and with medium or low scientific validity. Most studies (24) reported on the effects of different pharmacological options or nutritional supplementation (10 RTCs): acetazolamide (6), dorzolamide (3), methazolamide (1), brimonidine tartrate (1), ranibizumab (1), raubasine (1), valproic acid (1), triamcinolone (1), deflazacort (1), taurine+diltiazem+vitamine E (1), omega-3 fatty acids (3), lutein (3), and vitamin A+vitamin E (1). The remaining selected studies mainly reported on the effects of hyperbaric oxygen therapy (2), cell or tissue transplantation (3), retinal prostheses or chips (3), lenses (3) and surgery (3). Some studies assessed treatments for associated factors with RP, such as cystoid macular edema (14), cataracts (1) and myopia (1). Available studies for carbonic anhydrase inhibitors for the treatment of cystoid macular edema associated with RP are usually of a very small sample sizes and statistical analysis of results are not performed. Satisfactory results to date have been obtained using oral acetazolamida or metazolamida at a dose of 500 mg/d. However, a major limitation of this treatment is the side effects, which are common and limit the period over which the patient will tolerate the drug. No relevant side effects were reported for interventions included in this review that have shown a certain degree of effectiveness. From the results of an RTC it has been recommended that most adults RP patients must take vitamin A as retinyl palmitate in 15,000IU/day supplements under medical supervision. Although no serious safety problems related to recommended dose have been encountered so far, the long-term safety of taking high dose vitamin A supplements for many decades is uncertain. Moreover, the study and its recommendations are controversial, therefore, greater benefit should need to be proven before continue recommending the use of vitamin A in RP. On the basis of the patient consultation, the major concerns expressed by respondents were the difficulties in the development of activities of daily living and reduced quality of life. This fact results in a deficient and unsatisfactory social and labour integration. However, those outcomes were very scarcely addressed by the studies. Patients also suggested that psychological and rehabilitation therapy may be useful to accept the diagnosis and to learn how tomanage their health condition. However, no studies informing on rehabilitation or psychological therapy were included. Most respondents are skeptical about the development of a definitive curative treatment for RP while their expectations are focused on the research on drugs that might inhibit or at least slow the progression of RP. CONCLUSIONS: Great heterogeneity exists of studies on the safety and efficacy of treatments for RP. High-quality studies are scarce. In general, existing studies do not address the concerns and needs expressed by patients in our consultation experience. To date, according to available evidence, there is no effective treatment that can prevent or reverse the vision loss of RP. The therapeutic approach is restricted to slowing down the degenerative process and treating complications (macular edema, cataract, etc.). There is currently some evidence to support recommending vitamin A (15,000 IU/d) under medical supervision to slow down the disease effects. However, this recommendation is controversial. Other supplements like docosahexaenoic acid and lutein have shown some statistically significant beneficial effect in general forms of RP. Oral acetazolamide or methazolamide at a dose of 500 mg/d may be useful in the treatment of cystoid macular edema associated to RP. However, there is not yet enough evidence on their effectiveness and a possible rebound after discontinuing treatment could occur. Furthermore, side effects are common, limiting the period during which the patient tolerates the drug. Finally, non-randomized observations demonstrated improved visual function in patients with RP after hyperbaric therapy. More research from larger randomized trials and with longer follow-up is needed to confirm these findings and analyze the effectiveness of other treatments. However, new therapeutic strategies, such as gene therapy, neuroprotection, retinal cell transplantation, and retinal prosthesis, are emerging from intensive research.

Authors' methods: Systematic review of published literature with no time limits until February 2011. MEDLINE Y PREMEDLINE, EMBASE, CENTRAL, CINAHL, SCOPUS, SCI, IBECS, LILACS, TRIP DATABASE and some grey literature sources were searched. The search strategy combined controlled vocabulary and free text terms. In addition, a manual search was performed with the references of articles included. Original studies published in English or Spanish that assessed the effectiveness and safety of any therapy or device for typical RP were selected. Both experimental and observational designs assessing at least three patients were included. Selected outcome measures were clinical status and patientbased factors. The assessment of methodological quality of the included randomized clinical trials (RCT) was conducted according to the criteria of Scottish Intercollegiate Guidelines Network (SIGN) and by mean of Jadad scale. Data are presented through narrative synthesis. Experience and perspectives of RP patients in Spain regarding their disease were explored by means of a consultation exercise. Patients provided data on both their trajectory of care, treatments used, self-perceived health problems associated with RP, and the information and health needs regarding care and treatment. The variables and pathways identified allowed us to assess the extent to which research on RP have addressed those issues so far.

Project Status: Completed

Year Published: 2012

URL for published report: https://sescs.es/manejo-terapeutico-de-la-retinosis-pigmentaria/

English language abstract: An English language summary is available

Publication Type: Full HTA

Country: Spain

Organisation Name: Canary Health Service

Contact Address: Dirección del Servicio. Servicio Canario de la Salud, Camino Candelaria 44, 1ª planta, 38109 El Rosario, Santa Cruz de Tenerife

Contact Name: sescs@sescs.es

Contact Email: sescs@sescs.es