Characteristics of patients with normal (Group A) and abnormal (Group B) 6MWT; results represent median (range) unless otherwise indicated.

* Missing data for 2 patients. ** In combination with chronic transfusion in 6 patients in group A and in 3 patients in group B. BMI, Body Mass Index; G6PD, Glucose 6 Phosphate Dehydrogenase; VOC, Vaso-Occulsive Crisis having required an hospitalisation during the last 4 years; ACS, Acute Chest Syndrome; Severe infections: septicemia, osteomyelitis, meningitis; FEV, Forced Expiratory Volume in 1 second; VC, Vital Capacity; TLC, Total Lung Capacity; % PV, Per Cent of the predicted value; 6MWT, 6-Minute Walk Test; MCV, Mean Cell Volume; LDH, Lactate Dehyrogenase. Characteristics of patients with normal (Group A) and abnormal (Group B) 6MWT; results represent median (range) unless otherwise indicated.