A modified Delphi approach to standardize low back pain recurrence terminology.

Lack of standardization of terminology in low back pain (LBP) research has significantly impeded progress in this area. The diversity in existing definitions for a 'recurrence of an episode of LBP' and 'recurrent LBP' is an important example. The variety of definitions used by researchers working in this area has prevented comparison of results between trials and made meta-analyses of this data unfeasible. The aim of this study was to use a modified Delphi approach to gain consensus on definitions for a 'recurrence of an episode of LBP' (e.g. outcome event) and for 'recurrent LBP' (e.g. patient population). Existing definitions for both constructs were classified into the main features comprising the definition (e.g. 'duration of pain') and the items that defined each feature (e.g. 'pain lasting at least 24 h'). In each round, participants were asked to rate the importance of each feature to a definition of a 'recurrence of an episode of LBP', and a definition of 'recurrent LBP' and rank the items (defining each feature) in order of decreasing importance. Forty-six experts in LBP research, from nine different countries, participated in this study. Four rounds were completed with responses rates of 94, 91, 83, and 97% in rounds 1, 2, 3, and 4, respectively. Consensus definitions were reached in both areas with 95% of panel members supporting the definition of a 'recurrence of an episode of LBP' and 92% of panel members supporting the definition of 'recurrent LBP'. Future research is necessary to evaluate these definitions.