This distinction was less apparent for COT, which correlated
strongly with both the PAQ physical limitation and WIQ
distance scores (1-minute improvement in COT leads to an
average improvement in PAQ of 3.9 and in WIQ of 5.6; r
versus COT is 0.62 for PAQ and 0.66 for WIQ; both
P0.001) with no significant interaction with treatment
group (P0.26).