European journal of pain : EJP
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Multicenter Study
Does attrition bias longitudinal population-based studies on back pain?
Longitudinal population studies are a keystone in describing the course of back pain over time. Yet, potential bias because of repeated attrition has received little attention. This study aims to identify those back pain related indicators most susceptible to bias and to discuss practical consequences for back pain research. ⋯ The representativeness of the sample is consecutively reduced because of differential attrition over the different measurement points. Despite this, bias due to attrition has a marginal impact on the point estimates of virtually all back pain related outcomes.