CRD Summary: The review concluded that treatment with intravenous (IV) iron over a 60-day period may increase reticulocyte count and ferritin levels in comparison with oral administration or no iron.  The use of nondextran IV iron may also increase haemoglobin and haematocrit levels. However, the uncertainty about between-study differences means that the reliability of the authors’ conclusions is unclear.

CRD Commentary: There was a clearly stated review question and clear inclusion criteria. Several appropriate sources were searched without language restrictions for published and unpublished studies, thereby minimising publication and language bias. Appropriate review methods were also used to minimise error and bias in the study selection and quality assessment processes, although it is unclear whether these methods were used for the data extraction. The exclusion of studies with unavailable raw data or limited sample sizes may mean that some relevant studies were missed.  Statistical heterogeneity was assessed, though the source of the heterogeneity was not fully investigated.  However, the studies included very different participant populations and there may well be clinical heterogeneity present; in view of this, the pooling of studies may not have been appropriate. In summary, the uncertainty about between-study differences means that the reliability of the authors’ conclusions is unclear.