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Table 2 Application of summary approaches to paroxetine vs placebo for major depression in adults

From: Patient-reported outcomes in meta-analyses -Part 2: methods for improving interpretability for decision-makers

Outcomes Estimated risk with Placebo Absolute reduction in risk with Paroxetine Relative effect (95% CI) Number of participants (studies) Confidence in effect estimate 1 Comments
(A) Standard deviation units The depression score in the paroxetine groups was on average 0.31 SDs (0.24 to 0.38 lower than in the placebo groups)   --- 5736 (34) OO2,3 low As a rule of thumb, 0.2 SD represents a small difference, 0.5 moderate, and 0.8 large (Cohen, 1988)
(B) Natural units       
Major depression measured on Hamilton Rating Scale for Depression, generally scored from 0 to 50, higher scores indicate more severe depression The mean depression scores with placebo ranged from 3.1 to 11.3 The mean depression score in the intervention groups was on average 2.47 (1.91 to 3.03) lower 5736 (34)   OO2,3 low Scores estimated based on an SMD of 0.31 (95% CI 0.24 to 0.38)The minimal important difference on the 0 to 50 depression scale is 7 points. Although the depression score was on average only 2.47 lower, the corresponding NNT is 11
(C) Risk difference 50 per 100 patients 39 per 100 patients OR=1.64 (95% CI 1.47 to 1.84) 5736 (34) OO2,3 low This approach uses binomial and equal variance assumptions and baseline risks, and demonstrates that for every 100 patients treated with paroxetine, 11 will achieve important improvement
   Differences in proportion achieving important improvement     
   0.11 (95% CI 0.07 to 0.16) in favor of paroxetine     
(D) Ratio of means --- --- Ratio of means 5736 (34) OO2,3 low Weighted average of the mean depression score in paroxetine group divided by mean depression score in placebo. RoM method provides similar effect estimates compared with the traditionally used standard deviation unit, with SMDs of 0.2, 0.5, and 0.8, corresponding to increases in RoM of approximately 8%, 22%, and 37%, respectively (Friedrich 2011).
    1.27 (1.18 to 1.36)    
(E) Minimal important difference units The depression score in the paroxetine groups was on average 0.38 (95% CI 0.30 to 0.47) minimal important difference units less than the control group   --- 5736 (34) OO2,3 low An effect less than half the minimal important difference suggests a small effect
  1. Note: Investigators measured depression using different instruments, higher scores indicate more severe depression. 1Quality rating from 1 (very low quality) to 4 (high quality); 2Evidence limited by heterogeneity between studies; 3Evidence limited by risk of bias (i.e. missing participant data and potential for selective reporting bias).