has part has_specified_input is_specified_output_of bearer of bearer_of is bearer of participates in is member of count counting drug-drug interaction information content entity frequency of exposure information Among 2712 patients age 65 or older recruited at hospital admission and exposed to at least one potential drug drug interaction, 1642 patients were exposed to at least one potentially moderate drug drug interaction, for a frequency of exposure of 60.5%. An information content entity that mentions both the number of individuals within a cohort that are exposed to a drug-drug interaction over a specified time period and the total number of individuals in the cohort. The number of individuals within a cohort that are exposed to a drug-drug interaction over a specified time period divided by the total number of individuals in the cohort. cohort role organism collection of organisms