Are older adults insufficiently included in clinical trials?-An umbrella review

Treatment guidelines are primarily based on randomized clinical trials (RCTs). RCTs tend to some extent to exclude older adults despite the fact that physicians need guidance when treating this patient group. By summarizing existing literature, we aimed to (a) quantify the proportion of RCTs and other clinical studies (CTs) that did not adequately include older adults; (b) identify the main barriers for this non-inclusion; and (c) identify suggested solution for inclusion of older adults in RCTs and other CTs. In this umbrella review, Embase and PubMed were searched for relevant papers, and 2701 papers were identified. The subsequent screening resulted in 22 papers. The Critical Appraisal Skills Program was used as quality assessment tool to evaluate these 22 papers. We found that: (a) The most frequent outcome designating missing inclusion of older adults was the use of age limit as exclusion criterion in studies-the proportion of this was 10%-60%; (b) barriers for inclusion were mainly exclusion criteria, logistic challenges and financial constraints; and (c) more extensive inclusion would require more explicit inclusion criteria, merely application of exclusion criteria when absolutely needed, change of researchers' attitude, further inclusion of supporting relatives to overcome the logistical challenges and more financial funding.