Fig. 1

Methotrexate effect on VOC frequency, pain, and physical functioning. a Comparison of the number of VOC episodes recorded during a trimester that preceded the study and during the 12-week MTX treatment. b McGill Pain Index (MPI): the scores obtained at the end of the 12-week course of MTX were compared to those from week 0. The results of the McGill pain questionnaire administered to patients that reported at the last follow-up visit general clinical improvement (graded ≥5 in a scale of 0–10) are shown. c Longest uninterrupted pain-free period in between crises as perceived by the patients. d Chronic pain intensity: Each circle represents a patient, whose number is indicated. The position of the circles indicates the intensity of the avascular osteonecrosis-associated pain reported by individual patients after 12 weeks of MTX treatment plotted on a scale, in which 0 represents no pain and 1.0 represents the maximal baseline chronic pain. The 50% cutoff is indicated by the dashed line and data points at or under this level are shown as open circles. The P value was calculated with the Wilcoxon signed-rank test by comparing the median intensity of 0.5 (95% CI 0.05–1.0) at the last follow-up visit to the maximal baseline chronic pain before treatment (1.0). e SF-36 physical functioning (PF) subscale: scores obtained at weeks 0, 6, and 12 for patients with and without avascular osteonecrosis (AVN) are plotted in 25–75% interquartile boxes with whiskers set at 5 and 95 percentiles. The medians are indicated