Study | BMJ | Cochrane* | HTA | Comments |
---|---|---|---|---|
Dorr 1986 [22] | 2/39 vs 4/50 | 2/39 vs 4/50 | 2/39 vs 4/50 | Identical |
Skinner 1989 [17] | NR | 3/80 vs 13/100 | 4/89 vs 12/91 | As Table 1 above, plus an additional error: BMJ calculates 25% rather than the reported 24% for numerator |
(1-year data) | ||||
Ravikumar 2000 [18] | 6/91 vs 22/89 | NR | 6/89 vs 22/91 | |
(13-year data) | ||||
Baker 2006 [12] | 1/40 vs 6/41 | 1/40 vs 3/41 | 1/40 vs 6/41 | Selection difference: |
BMJ, HTA and Liang [7] all report 1/40 vs 6/41; Cochrane omits 3/41 which were classified as planned or awaiting revision; the event had not taken place but was “planned” only, so was not counted | ||||
Keating 2006 [11] | NR | NR | NR | Identical |
Blomfeldt 2007 [9] | 4/60 vs 3/60 | 1/60 vs 0/60 | 0/60 vs 0/60 | Selection difference: |
Cochrane 1/60 is a “revision” described by Blomfeldt as a “wound revision”; only revision of implant counts as a revision in the HTA; the BMJ review figures include re-operations both on the contra-lateral side, not related to the implant, and for trauma of the lower limb. [10] | ||||
Macaulay 2008 [23] | 1/17 vs 0/23 | 1/17 vs 0/23 | 1/17 vs 0/23 | Identical |
Mouzopoulos 2008 [8] | 1/43 vs 3/43 | 1/43 vs 5/43 | 1/39 vs 5/38 | Selection difference: |
Numerators: BMJ “excluded” 2 HA revisions from the analysis (so 3 rather than 5) but this was arguably not justified as the individuals had the outcome of interest and so should have been included; | ||||
Denominators: As Table 2. | ||||
3/24 errors = 13% | 2/24 errors = 8% | 6 analysed studies = a/B vs c/D = 24 variables | ||
6/24 selection differences = 25% | 5/24 selection differences = 21% |