Patient and clinic factors predictive of missed visits and inactive status in a multicenter clinical trial. The Macular Photocoagulation Study Group

Abstract

Obtaining complete patient follow-up in clinical trials is important for the analysis of treatment results and for good patient care. Incomplete data can introduce bias into study results and can alter conclusions concerning treatment efficacy. The purpose of this study was to explore in a case-control design patient and clinic factors that may be associated with missed visits or inactive status within three clinical trials conducted as part of the Macular Photocoagulation Study. All inactive patients, all patients with any missed visits, and a random sample of patients with no missed visits were selected for interview. A total of 175 patients (60% of 292 selected) participated in the study. Two factors were found to be significantly associated (P less than .05) both with inactive status and with having any missed visits: health problems and travel costs. Several patient and clinic factors were found to be associated only with inactive status. These included change in marital status since joining the study, retirement since study entry, unsatisfactory interactions with the study physician or clinic coordinator, too little time spent with the study physician, and patient's belief that participants should be paid to participate in clinical trials. Distance from the clinic greater than 100 miles, in addition to health problems any time during follow-up and problems with travel costs, was found to be associated only with having any missed visits. This study emphasizes the importance of maintaining good patient-staff interactions and sensitivity to the events in a patient's life in order to obtain complete patient follow-up.