Table 1

 Baseline characteristics of creatine and placebo groups

Creatine(n = 18, 10 male)Placebo(n = 20, 13 male)
Data are presented as group mean (SD) values.
FEV1, forced expiratory volume in 1 second; FVC, forced vital capacity; Tlco, carbon monoxide transfer factor; MIP, maximum inspiratory pressure; BMI, body mass index; BM, body mass; FFM, fat-free mass; FM, fat mass; V˙o2, peak oxygen uptake; IET, incremental exercise test; CWR, constant work rate exercise test; ISWT, incremental shuttle walk test; ESWT, endurance shuttle walk test; RPE, rating of perceived exertion; SGRQ, St George’s Respiratory Questionnaire.
Age (years)61.7 (8)63.7 (9.7)
Cigarette (pack years)52 (32)52 (30)
Pulmonary function
    FEV1 (l)1.12 (0.3)1.13 (0.5)
    FEV1 (% predicted)45.4 (14)45.4 (16)
    FEV1/FVC35.9 (10.6)40.9 (9.5)
    Tlco (% predicted)46.4 (23)46.6 (25)
    MIP (cm H2O)62.3 (25)61.1 (29.1)
Body composition
    Total BM (kg)61.9 (10.4)65.5 (21.5)
    FFM (kg)43.3 (8.9)42.2 (12.6)
    FM (kg)18.6 (8.2)23.3 (11.7)
    BMI (kg/m2)23.2 (3.6)24.3 (6.6)
Upper limb muscle function
    Peak force (N)26.7 (8.2)25.6 (10.3)
    Total repetitions48.9 (14.5)50.6 (17.8)
Lower limb muscle function
    Peak torque (N.m)85.7 (26.6)82.2 (34.5)
    Total work (J)1833 (740)1648 (881)
Exercise capacity
    Peak work rate (W)59.0 (26.3)56.0 (29.0)
    Peak V˙o2 (IET, l/min)0.85 (0.39)0.86 (0.37)
    Lactate threshold (IET, l/min)0.55 (0.17)0.53 (0.24)
    Breathing reserve (IET, l/min)3.3 (8.2)8.2 (12.4)
    Peak dyspnoea (IET)6.7 (1.9)6.6 (1.7)
    Peak RPE (IET)7.0 (2.2)6.9 (2.0)
    Exercise time (CWR, s)164 (66)126 (44)
    End-ex dyspnoea (CWR)7.8 (1.9)6.5 (2.2)
    End-ex RPE (CWR)6.3 (2.7)7.3 (2.0)
    Distance walked (ISWT, m)331 (111)293 (142)
    Time walked (ESWT, s)340 (209)392 (297)
SGRQ
    Total score65.6 (14.0)67.9 (11.4)
    Activity domain82.5 (12.9)78.8 (14.4)
    Impact domain50.5 (16.3)56.0 (13.0)
    Symptoms domain80.4 (18.5)77.1 (14.8)