Univariate Associations with Number of Acute Exacerbations and COPD-Related Hospitalizations.

<p>6MWT denotes 6-minute walk test; SGRQ-AS St. George's Respiratory Questionnaire Activity Score; FEV₁ forced expiratory volume in 1 second; AE acute exacerbation; SGRQ-TS St. George's Respiratory Questionnaire Total Score; MMRC Modified Medical Research Council; and ref reference group.</p>§<p>Rate ratios calculated for a MCID of 30 m <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0060400#pone.0060400-Polkey1" target="_blank">[37]</a> for 6MWT and 4 units <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0060400#pone.0060400-Jones2" target="_blank">[42]</a> for SGRQ-AS. The regression coefficients (SE) in natural log risk per 30-m decrease in 6MWT predicting AEs and COPD-related hospitalizations are 0.0976 (0.0323) and 0.1946 (0.0516), respectively. The regression coefficients (SE) in natural log risk per 4-unit decrease in SGRQ-AS predicting AEs and COPD-related hospitalizations are 0.0712 (0.0206) and 0.1091 (0.0347), respectively.</p>†<p>N = 168.