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 .
Sputum eosinophilia predicts benefit from prednisone in smokers with chronic obstructive bronchitis.
A reliable predictor of benefit from corticosteroid treatment in patients with chronic airflow limitation is needed . In a single-blind , sequential crossover trial of placebo and prednisone ( 30 mg/day ) treatment , with each given for 2 wk , we investigated whether an increased proportion of sputum eosinophils ( > = 3 % ) predicts a beneficial effect of prednisone in smokers with severe obstructive bronchitis . Patients were seen before and after each treatment . Clinical measurements were made blind to the laboratory findings and vice-versa . Eighteen of 20 patients completed the study . Eight had sputum eosinophilia and similar clinical and physiologic characteristics to those of 10 patients without a finding of sputum eosinophilia . Only in patients with sputum eosinophilia did prednisone , as compared with placebo , produce a statistically significant and clinical ly important mean effect on effort dyspnea of 0.8 ( 95 % confidence interval [ CI ] : 0.3 to 1.2 ) , p = 0.008 , and in quality of life of 1.96 ( 95 % CI : 0.5 to 3.3 ) , p = 0.01 , associated with a small improvement in FEV1 of 0.11 L ( 95 % CI : - 0.04 to 0.23 L ) , p = 0.05 . In these patients , prednisone also produced a significant decline in the median sputum eosinophil percentage , from 9.7 % to 0.5 % ( p = 0.002 ) , eosinophil cationic protein ( ECP ) , from 6 , 000 microgram/L to 1,140 microgram/L ( p < 0.001 ) , and fibrinogen , from 25 . 3 mg/L to 5.4 mg/L ( p < 0.001 ) . These findings indicate that in smokers with severe airflow limitation , sputum eosinophilia predicts a beneficial effect of prednisone treatment . Improvement in FEV1 , after prednisone treatment in this population , is small , and may not be appreciated in clinical practice
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 .