Summary: meta-analysis of the effect of epoetin on transfusion
| Focus of analysis . | OR (95% CI)7-150 . | NNT (95% CI) . |
|---|---|---|
| All randomized studies, subcutaneous epoetin delivery | 0.380 (0.282-0.513) | 4.4 (3.6-6.1) |
| All randomized studies, subcutaneous epoetin delivery, higher quality (300-450 weekly dose) | 0.453 (0.330-0.621) | 5.2 (3.8-8.4) |
| All randomized studies, subcutaneous epoetin delivery, lower quality (300-450 weekly dose) | 0.137 (0.060-0.313) | 2.6 (2.1-3.8) |
| Focus of analysis . | OR (95% CI)7-150 . | NNT (95% CI) . |
|---|---|---|
| All randomized studies, subcutaneous epoetin delivery | 0.380 (0.282-0.513) | 4.4 (3.6-6.1) |
| All randomized studies, subcutaneous epoetin delivery, higher quality (300-450 weekly dose) | 0.453 (0.330-0.621) | 5.2 (3.8-8.4) |
| All randomized studies, subcutaneous epoetin delivery, lower quality (300-450 weekly dose) | 0.137 (0.060-0.313) | 2.6 (2.1-3.8) |
Data from Seidenfeld et al.3 (Tab21)
OR indicates odds ratio; and NNT, number needed to treat.
Odds of transfusion for epoetin-treated patients relative to the odds of transfusion for control patients. The odds of transfusion for the combined control study arms (from those studies with a known followup duration) was estimated using a logistic normal model and the point estimate for a 12-week follow-up duration.68 For the NNT for all randomized studies that delivered epoetin subcutaneously, the estimate was 0.99, corresponding to a probability of 0.498 (odds = probability of transfusion/(1 − probability of transfusion)). From this and the summary odds ratio, the odds of transfusion for the combined epoetin-treated study arms was calculated as 0.380 × 0.99, or 0.376, corresponding to a probability of 0.273. NNT is equal to the reciprocal of the absolute risk reduction,69 or 1/(0.498 to 0.273) = 4.44. The 95% CI are 1/(0.498 to 0.216) = 3.55 to 1/(0.498 to 0.335) = 6.13.