“…(a) Funnel plot; (b) Contour-enhanced funnel plot; (c) Egger’s graph and Begg’s test, CI, confidence interval; se, standard error; SMD, standardised mean difference; SND, standard normal deviate; 6MWD, six-minute walk distance. References [ 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 ] are cited in supplementary materials.…”