Convergent validity of a person-dependent definition of a low back pain flare.

Unlabelled: Exacerbations of existing low back pain (LBP) or new LBP episodes are colloquially referred to as "flares". Although the experience of flares is common to many people with LBP, few validated measures enable people to self-report if they are experiencing a flare. This study examined the convergent validity of a person-dependent definition of flares ("a worsening of your low back pain that lasts from hours to weeks") as compared to (1) LBP intensity, (2) LBP-related pain interference, and (3) analgesic use, in a large, prospective research study of Veterans with LBP.

Evaluating the representativeness of a cohort study of low back pain: Using electronic health record data to make direct comparisons of study participants with non-participants from the study population.

Representativeness is an important component of generalizability. Few studies have rigorously examined the representativeness of randomized trials or observational studies of pain or musculoskeletal conditions with regards to a wide range of factors beyond age, sex, race, and ethnicity. We conducted the first study of a pain condition that uses individual-level data to directly compare the enrolled study sample to the population from which it was drawn.