Site visits in a multicenter ophthalmic clinical trial.

Site visits were conducted to 19 clinical centers in a large multicenter ophthalmologic clinical trial, the Early Treatment Diabetic Retinopathy Study (ETDRS). The purpose of these site visits was to ensure the consistency of study procedures among clinics and to verify that these procedures were being carried out in accordance with the ETDRS Manual of Operations. The five major aspects of this quality control program are as follows: To monitor and review each clinical center's organization and procedures; To promote comparability of participating centers in all important aspects of the clinical trial; To gain more understanding about special problems facing individual clinical centers; To establish good rapport between the site visitor and clinic staff to aid future clinic monitoring; To promote and maintain enthusiasm for the study. The ETDRS clinical center site visits were conducted by using an observational approach. Presite visit preparations included the formation of a site visit agenda and the design of a site visit form, providing a guide for the site visitor, and a list of the topics that were to be reviewed at each center. Important concerns common to all site visits proved beneficial in the ETDRS.