Thus the distribution method can only be used to calculate an absolute MCID as there is no st and ard deviation of baseline score for a relative measure .
The anchor-based method relates the change in
To the Editor : The same patient outcome data from clinical trial results , when presented as absolute or relative changes , may appear different in magnitude .
Recommendations are to report both absolute and relative , or at least baseline , data from which to calculate absolute values [ 1 , 2 ] .
To inform clinical practice , outcome improvements , whether relative or absolute , must be statistically significant and clinical ly meaningful .
A minimal clinical ly important difference ( MCID ) should inform sample size calculations for clinical trials .
Blood eosinophils to direct corticosteroid treatment of exacerbations of chronic obstructive pulmonary disease: a randomized placebo-controlled trial.
RATIONALE Exacerbations of chronic obstructive pulmonary disease ( COPD ) and responses to treatment are heterogeneous . OBJECTIVES Investigate the usefulness of blood eosinophils to direct corticosteroid therapy during exacerbations . METHODS Subjects with COPD exacerbations were entered into a r and omized biomarker-directed double-blind corticosteroid versus st and ard therapy study . Subjects in the st and ard arm received prednisolone for 2 weeks , whereas in the biomarker-directed arm , prednisolone or matching placebo was given according to the blood eosinophil count biomarker . Both study groups received antibiotics . Blood eosinophils were measured in the biomarker-directed and st and ard therapy arms to define biomarker-positive and -negative exacerbations ( blood eosinophil count > and ≤ 2 % , respectively ) . The primary outcome was to determine noninferiority in health status using the chronic respiratory question naire ( CRQ ) and in the proportion of exacerbations associated with a treatment failure between subjects allocated to the biomarker-directed and st and ard therapy arms . MEASUREMENTS AND MAIN RESULTS There were 86 and 80 exacerbations in the biomarker-directed and st and ard treatment groups , respectively . In the biomarker-directed group , 49 % of the exacerbations were not treated with  prednisolone . CRQ improvement after treatment in the st and ard and biomarker-directed therapy groups was similar ( 0.8 vs. 1.1 ; mean difference , 0.3 ; 95 % confidence interval , 0.0 - 0.6 ; P = 0.05 ) . There was a greater improvement in CRQ in biomarker-negative exacerbations given placebo compared with those given prednisolone ( mean difference , 0.45 ; 95 % confidence interval , 0.01 - 0.90 ; P = 0.04 ) . In biomarker-negative exacerbations , treatment failures occurred in 15 % given prednisolone and 2 % of those given placebo ( P = 0.04 ) . CONCLUSIONS The peripheral blood eosinophil count is a promising biomarker to direct corticosteroid therapy during COPD exacerbations , but larger studies are required
Thus the distribution method can only be used to calculate an absolute MCID as there is no st and ard deviation of baseline score for a relative measure .
The anchor-based method relates the change in
To the Editor : The same patient outcome data from clinical trial results , when presented as absolute or relative changes , may appear different in magnitude .
Recommendations are to report both absolute and relative , or at least baseline , data from which to calculate absolute values [ 1 , 2 ] .
To inform clinical practice , outcome improvements , whether relative or absolute , must be statistically significant and clinical ly meaningful .
A minimal clinical ly important difference ( MCID ) should inform sample size calculations for clinical trials .