Older patients:
Cherubini et al extracted data from 251 ongoing clinical trials regarding heart failure from the World Health Organization Clinical Trials Registry, 25 % trials excluded patients from based on an arbitrary upper age limit. 43 % of the trials had one or more poorly exclusion criteria that could limit participation of older patients such as comorbidity described in a non-specific manner, use of medications that would not impact the study protocol, and visual and hearing impairment that would not lead to safety concerns \cite{Cherubini2011} \cite{Gurwitz2014}. Among 839 trials of Ischemic Heart Disease, Bourgeois et al showed that 53 % of trials excluded participants based on older age \cite{Bourgeois_2017}
Results derived from trials. Due to age related differences in pathophysiology of certain diseases, difference in pharmacokinetics and pharmacodynamics of drugs based on age that can impact tolerability and toxicity, data extrapolated from younger adults cannot be extrapolated to the elderly
\cite{Bourgeois2017}. While the FDA guidelines in 1989 stated that there is no clear basis to exclude participants based on age, the NIH revitalization Act of 1993 was limited to women and minorities and did not include provisions for older patients
https://www.fda.gov/regulatory-information/search-fda-guidance-documents/study-drugs-likely-be-used-elderly \cite{bookshelf}