Sir,
Derek Enlander’s comments refer to Table 4 in our paper1 which describes the association of baseline characteristics with change in physical function at follow-up. It does not describe the outcome which can be found in Table 2. This shows an improvement in fatigue (−6.8; 95% CI −7.4 to −6.2; P < 0.001), physical function (4.4, 95% CI 3.0 to 5.8; P < 0.001), anxiety, depression and pain at follow-up.
In addition, as we state in the methods, the scores from the different inventories were re-scaled, so that a regression coefficient of 1 represents a 10% change in the score. Hence, the coefficient of −0.47 (95% CI −0.58 to −0.36) for the mean change in (re-scaled) SF-36 physical function per unit (re-scaled) Chalder Fatigue score at baseline, indicates that each 10% increment in baseline Chalder Fatigue (i.e. 3.3 points on the original 0 to 33 scale) is associated with a mean change of −4.7 points (95% CI −5.8 to −3.6 points) on the original 0 to 100 SF-36 scale at follow-up. Similarly, the coefficient of 0.81 (95% CI 0.75 to 0.87) for the mean change in (re-scaled) SF-36 physical function per unit (re-scaled) SF-36 score at baseline, indicates that each 10% increment in baseline physical function (i.e. 10 points on the original 0 to 100 SF-36 scale) is associated with a mean change of 8.1 points (95% CI 7.5 to 8.7 points) on the original 0 to 100 SF-36 scale at follow-up.
In summary, our paper shows that patients showed improvements in fatigue, physical disability, anxiety, depression and pain. Table 4 referred to by Derek Enlander show that worse fatigue and disability at assessment predict a worse outcome for disability at follow-up.
You can read the rest of this comment here: https://academic.oup.com/qjmed/article/107/3/247/1569245/Response-to-Derek-Enlander
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Source: Crawley E. Response to Derek Enlander. QJM. 2014 Mar;107(3):247. doi: 10.1093/qjmed/hct171. Epub 2013 Aug 22. https://academic.oup.com/qjmed/article/107/3/247/1569245/Response-to-Derek-Enlander (Full article)