The pitfalls of a systematic MEDLINE review in palliative medicine: symptom assessment instruments.

The Medical Literature Analysis and Retrieval System Online (MEDLINE) database provides many references for reviews, but many relevant articles are missed, especially when the topic is complex. Reported here is the detailed methodology of a PubMed search of MEDLINE augmented by a related articles link search. Of 1181 citations identified, through a PubMed search, 10 articles met the inclusion criteria. Fifty-one were identified through the related articles link; of which 43 were not detected by standard searches using medical subject heading terms. More than 50% were identified using the related articles link. Only 14% of relevant articles were identified using the standard PubMed MEDLINE search. The related articles link is not included in methodologic recommendations for systematic literature reviews but this experience suggests that it is a useful tool in PubMed for reviewing complex evidence. Related links searches are proposed in any systematic PubMed MEDLINE literature review in palliative medicine.