Demographic characteristics | NETT(n = 389) | NAS(n = 420) | p Value |
Age (years) | 67 (6) | 68 (9) | 0.9 |
Pack-years | 66 (30) | 39 (27) | <0.001 |
FEV1 (% predicted, post-BD)* | 28 (7) | 92 (11) | |
Median (IQR) modified BODE score† | 5 (3) | NA | |
Gender (% male) | 64% | 100% |
Values are mean (SD) unless otherwise stated.
BD, bronchodilator; FEV1, forced expiratory volume in 1 s; IQR, interquartile range; NAS, Normative Aging Study; NETT, National Emphysema Treatment Trial.
*FEV1 percentage predicted values for the NETT and NAS are based on the prediction equations of Crapo et al;36 however, the NAS-1988 standards were used in the selection of the control group.
†Modified BODE score incorporates the University of San Diego Shortness of Breath Questionnaire.