Table 4 Results of MA and data synthesis
Variable | Number (%) |
|---|---|
Know pre/post-intervention data and post-intervention data (Yes), n = 364 | 161 (44.2) |
Investigating the efficacy of an intervention, and the pre- and post-intervention (pre/post) values for each group with the correlation value were not available, n = 156 | |
 Used pre/post-difference values for each group | 77 (49.4) |
 Used post values for each group | 40 (25.6) |
 Used (pre/post) values for each group and use correlation value | 39 (25.0) |
If the (pre/post) values for each group are the only data available but the correlation value is not available, what did you do? n = 157 | |
 Request authors of original articles | 53 (33.8) |
 Use a default correlation value of 0.5 if no response from authors | 28 (17.8) |
 Analyze several tests with correlation values ranging from 0.1–0.9 if nonresponse from authors | 32 (20.4) |
 I do not know what is meant by the correlation value | 44 (28) |
Using raw data (such as mean, SD) or analyzed results (such as p-values) in the MA, n = 382 | |
 Use raw data | 221 (57.9) |
 Use analyzed result | 26 (6.8) |
 It is dependent on case by case | 135 (35.3) |
MA of adjusted or non-adjusted data, n = 372 | |
 Unadjusted data alone | 118 (31.7) |
 Adjusted data alone | 58 (15.6) |
 Meta-analyze both ways | 163 (43.8) |
 Select data that have higher level of nominal significance | 9 (2.4) |
 I don’t know adjusted and unadjusted data | 24 (6.5) |
Repeating the same data of placebo in many subgroups when analyzing subgroup based on the concentration of the drug used, n = 350 | |
 Yes | 75 (21.4) |
 No, because the same population cannot be pooled twice in one MA. So the author should only perform subtotal results. | 275 (78.6) |
 Ever extracted Pearson correlation for analysis, n = 370 | 96 (25.9) |
 Ever extracted Spearman correlation for analysis, n = 368 | 71 (19.3) |
Dealing with Pearson and Spearman correlation in the MA (combining or separating), n = 190 | |
 Analyze each method separately in two MAs | 127 (66.8) |
 Use only Pearson method | 34 (17.9) |
 Combine both in one MA | 23 (12.1) |
 Use only Spearman method | 6 (3.2) |