Fig. 7From: The magnitude and temporal changes of response in the placebo arm of surgical randomized controlled trials: a systematic review and meta-analysisMeta-analysis of pain trials grouped by follow-up time. Pooled SMD estimates for 11 trials with pain intensity as the primary outcome at multiple follow-up visits, grouped by follow-up time (in months). SF-MPQ McGill Pain Questionnaire, NRS numerical rating scale, VAS visual analogue scale, SF-36 Short Form Health Status Questionnaire, WOMAC Western Ontario and McMaster Universities Osteoarthritis IndexBack to article page