Systematic reviews and meta-analyses.

You are the medical director of your local hospice. After the annual budget review, the hospice’s director comes to you to see if there are treatments being given that are not supported by evidence. In particular, use of supplemental home oxygen was identified as a significant expenditure. The director asks your opinion about whether supplemental oxygen is likely to relieve shortness of breath in patients who are not hypoxemic. During an evidence-based medicine course, you learned that systematic reviews provide one of the strongest levels of evidence for guiding treatment decisions. You search PubMed and find a systematic review and metaanalysis addressing this question. The review concludes ‘‘oxygen did not provide symptomatic benefit for cancer patients with refractory dyspnoea who would not normally qualify for home oxygen therapy.’’ Does this mean the hospice should stop providing nonhypoxemic patients with home oxygen? Before making a change in policy that affects so many patients, you would like to really understand the review and its results. How can you evaluate the validity of this finding and determine whether you should apply it to your patients? The objectives of this article are to describe the methodology of systematic reviews and meta-analyses, address the current status of systematic reviews and meta-analyses in palliative care, and provide guidelines for evaluating the quality of and interpreting the results of systematic reviews and meta-analyses. Table 1 summarizes the key concepts we will discuss.