Pentoxifylline for diabetic retinopathy.

BACKGROUND: There is increasing evidence that capillary occlusion plays an important part in the development of diabetic retinopathy. Disaggregants, such as pentoxyfilline may influence the outcome and progression of diabetic retinopathy, but no systematic review of the literature on its efficacy and safety has been published to examine this hypothesis. OBJECTIVES: The aim of the current research was to review the literature in a systematic way in order to assess the effects of pentoxyfilline for diabetic retinopathy in methodologically robust trials. The null hypothesis was that pentoxyfilline has no influence on the progression of diabetic retinopathy or blindness. SEARCH STRATEGY: A systematic search of electronic databases was carried out to identify publications. Relevant papers, written in any language, were accessed and assessed for data. SELECTION CRITERIA: Only randomized controlled clinical trials (RCTs) evaluating the effects of pentoxyfilline in the treatment of diabetic retinopathy were to be included. DATA COLLECTION AND ANALYSIS: Two authors independently assessed studies for inclusion criteria and for risk of bias. MAIN RESULTS: A total of 97 publications were identified by the electronic search and two authors checked the abstracts. Of these, 17 were identified as potentially relevant trials providing information about treatment of patients with diabetic retinopathy using pentoxyfilline and were read in full. Unfortunately, no publication fulfilled our inclusion criteria. AUTHORS' CONCLUSIONS: No sound research to date has examined the treatment of diabetic retinopathy with pentoxyfilline in such a way as to indicate whether this form of intervention has a significant impact on the natural history of this clinical condition. The potential role of this substance in the treatment of diabetic retinopathy remains open to debate, and it is suggested that future research focusing on patient-relevant outcomes takes the opportunity of addressing this important issue directly.

Vitamin C and superoxide dismutase (SOD) for diabetic retinopathy.

BACKGROUND: There is increasing evidence that diabetic retinopathy is caused by the action of free radicals. Radical scavengers like vitamin C and superoxide dismutase (SOD) may influence the outcome and progression of diabetic retinopathy, but no systematic review of the literature has been published to examine this hypothesis. OBJECTIVES: The aim of the current research was to review the literature in a standard systematic way in order to assess the effects of vitamin C and superoxide dismutase on diabetic retinopathy in methodologically robust trials. SEARCH STRATEGY: We tried to obtain studies from computerised searches of MEDLINE, EMBASE, CINAHL, Web of Science and The Cochrane Library. SELECTION CRITERIA: Only randomized clinical trials (RCTs) that evaluated the effect of vitamin C, superoxide dismutase or both in the treatment of diabetic retinopathy were considered. DATA COLLECTION AND ANALYSIS: Two authors independently read all abstracts, titles or both and wanted to assess risk of bias and to perform data extraction. Discrepancies were planned to be resolved by consensus or by the judgement of a third author. MAIN RESULTS: A total of 241 publications were identified by the electronic searches. Of these, 28 were identified as potentially containing information about the treatment of patients with diabetic retinopathy using vitamin C or SOD and were read in full. No trial evaluated the treatment of diabetic retinopathy with vitamin C or SOD. AUTHORS' CONCLUSIONS: No research to date has adequately examined the treatment of diabetic retinopathy with vitamin C or SOD in such a way as to indicate whether this form of intervention has a significant impact on the progress of this clinical condition. The potential role of these substances in the treatment of diabetic retinopathy remains open to debate, and it is suggested that future research focusing on patient-oriented outcomes should address this important issue.