Underestimation of mortality following lung volume reduction surgery resulting from incomplete follow-up

Study objectives: Incomplete follow-up can bias interpretation of data that are collected in longitudinal studies, We noted that many patients failed to return for follow-up in a study of effect of lung volume reduction surge ry (LVRS) on quality of life (QOL), Accordingly, we designed this investiga tion to determine the reasons patients dropped out, and to assess differenc es between those who continued in the study (attendees) and those who did n ot (nonattendees), Design: Telephone survey. Subjects: Patients with advanced emphysema who had undergone LVRS and had p reviously agreed to participate in a longitudinal QOL study. Results: No differences were found with regard to age, gender, preoperative pulmonary function, or oxygen use between attendees and nonattendees. Long -term mortality in nonattendees (27%) was considerably greater than that se en in attendees (3%, p < 0.05). Distance from the hospital, financial burde n, and living out of the region were the most common reasons cited by survi ving nonattendees for their failure to return for follow-up. Conclusions: Studies reporting the long-term mortality after LVRS can be bi ased in the direction of underestimating the true value if they are comprom ised by incomplete follow-up.