Identifying the most important confounders when assessing the association between low-grade systemic inflammation and musculoskeletal pain: A modified Delphi study

OBJECTIVE: The association between low-grade systemic inflammation and musculoskeletal pain may be influenced by multiple factors. However, little is known about the relative importance of these factors, and few studies account for them. This Delphi study aimed to reach consensus on the most important confounders which influence the association between low-grade systemic inflammation and musculoskeletal pain.

METHODS: The panel consisted of 48 experts. In Round 1, the experts proposed what they believed were important confounders. In Round 2, the experts indicated for each confounder whether they believed it was important (yes/no). At least 50% of experts had to indicate the confounder was important to be considered in the final round. In Round 3, the experts rated the importance of each confounder on a 7-point Likert scale. Consensus was reached if ≥ 75% of the experts considered the factor either extremely or moderately important.

RESULTS: In Round 1, 120 confounders were proposed, which were synthesised into 38 distinct factors. In Round 2, 33 confounders met the criterion to be considered important. In Round 3, consensus was reached for 14 confounders: acute illness/trauma, immune disease, medication use, endocrine, nutritional, or metabolic disease, other musculoskeletal conditions, age, handling of blood samples, sex, cancer, body composition, pregnancy, cardiovascular disease, physical activity, and pain characteristics.

CONCLUSIONS: These findings provide insight in the complexity of the association between low-grade systemic inflammation and musculoskeletal pain. Some factors currently listed as confounders may be re-classified as moderators or mediators as insights progress.