CRD Summary: This review concluded that there was insufficient evidence to support the use of domperidone in gastroparesis and recommended further research. The conclusions were appropriately cautious, but search limitations reduced the likelihood of all relevant evidence being identified and made the included studies unlikely to be representative. It was not possible to determine the reliability of the conclusions.

CRD Commentary: The review addressed a reasonably clear research question. The review implied that patients with diabetic gastroparesis were included, however, the discussion section reveals that non-diabetic patients were also included. It was unclear whether study design was pre-specified, which may have led to subjective decisions regarding inclusion. The inclusion of only one database coupled with the number of unpublished studies (17 conference abstracts) identified from the reference lists of included studies alone, suggested that the search was not comprehensive enough to identify all relevant trials. There did not appear to be any systematic efforts to identify unpublished studies. Publication bias was not assessed in the report. It was unclear whether steps were taken to minimise the risk of error and bias in the processes of study selection and data extraction. The decision to use a narrative analysis was appropriate given the heterogeneity of the included studies.

The authors recognised the poor quality and heterogeneity among the primary studies. They graded the evidence as level 3 and reported a c-grade recommendation: poor evidence either in support of or against the use of domperidone in the treatment of diabetic gastroparesis. The authors made an appropriately cautious conclusion. The search was limited to one database, unpublished material was not sought and publication bias was not assessed. Thus, it was unlikely that all the relevant evidence was identified and there was a strong probability that the included studies were not representative. It was not possible, therefore, to determine the reliability of the conclusions.