Quality of Controlled Clinical Trials on Glaucoma and Intraocular High Pressure

• Published in: Journal of glaucoma Vol. 14; no. 3; pp. 190 - 195
• Main Authors: Llorca, Javier, Martínez-Sanz, Fernando, Prieto-Salceda, Dolores, Fariñas-Álvarez, Concepción, Chinchón, M Verónica, Quinones, Dolores, Delgado-Rodríguez, Miguel
• Format: Journal Article
• Language: English
• Published: United States Lippincott Williams & Wilkins, Inc 01-06-2005
• Subjects: Controlled Clinical Trials as Topic - standards; Controlled Clinical Trials as Topic - statistics & numerical data; Glaucoma; Humans; Intraocular Pressure; Ocular Hypertension; Publishing - standards; Publishing - statistics & numerical data; Quality Control; Research Design - standards
• ISSN: 1057-0829; 1536-481X
• DOI: 10.1097/01.ijg.0000159124.57112.69

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.