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Abstract #12467 Published in IGR 7-2
Quality of controlled clinical trials on glaucoma and intraocular high pressure
Llorca J; Martinez-Sanz F; Prieto-Salceda D; Farinas-Alvarez C; Chinchon MV; Quinones D; Delgado-Rodriguez MJournal of Glaucoma 2005; 14: 190-195
See also comment(s) by Anne Coleman •
AIM: To study the quality of controlled clinical trials on glaucoma. METHODS: Two hundred and twenty-six clinical trials published between 1980 and 1999 were selected from seven international ophthalmological journals. Their quality was assessed by four researchers with epidemiological skills using a structured questionnaire. RESULTS: Sample size was pre-estimated in 34 (15.0%) papers, which were of greater size (P = 0.05). Randomization was performed in 98.2% of the trials, although the procedure of randomization was scarcely reported. Masking was reported in 56.6% of the papers, and was more frequent in medical treatments (P < 0.001). The basal characteristics of the groups were compared in 139 papers (61.5%). Patient losses during the follow-up period were fully described in only 27 trials. Intention-to-treat analysis was used in 17 (7.7%) papers. Most trials reported P values, but a measure of effect (mean, proportion, or relative risk) appeared in only 16 trials (7.7%). Trials performed in the US more frequently compared baseline characteristics of the groups (P = 0.03), described the patient flow (P = 0.04), and used adequate statistical procedures (P = 0.03). Those trials that included a statistician or an epidemiologist among the authors were more commonly blinded (P = 0.06) and they always avoided the analyses of subgroups (P = 0.006). Several methodological issues have improved throughout the studied period. CONCLUSIONS: Several methodological characteristics should be improved when reporting a clinical trial on glaucoma. Using a checklist like that suggested by the CONSORT can help to achieve this.
Dr. J. Llorca, Division of Preventive Medicine and Public Health, University of Cantabria School of Medicine, Santander, Spain. llorcaj@unicam.es
