Lost but Not Forgotten: How to Manage Follow-Up Loss in Clinical Research.

Abstract

The interconnectedness of the modern world should make following patients and accessing their records much easier than in the past. For those of us old enough to remember, this once involved boxes full of papers, charts, microfiche records, images printed on radiographic films, and connecting with our patients via mailed letters. With modern electronic medical records and numerous means of electronic communication, this should be much easier. However, the demands on our patients' time are higher than ever before, mitigating some of these technological benefits. While all studies would benefit from 100% follow-up, real-world concerns lead to the inevitable loss of patients in research studies. Researchers should strive to lower and mitigate these losses and, when possible, explore potential bias introduced with attrition. Losses to follow-up risk lowering the validity of the research via the introduction of selection and attrition bias. Proper accounting for and reporting of patients throughout the inclusion, exclusion, and analysis of a study allows the reader to assess the amount of risk introduced by patient loss and its potential effect on the study outcomes and conclusion. Finally, when loss to follow-up occurs, it should be explicitly reported, accounted for by using appropriate statistical analyses (such as Kaplan-Meier), and its impact discussed in the interpretation of the results.