SAN FRANCISCO – Nearly half of outpatient antibiotics are prescribed without an infection-related diagnosis, according to a new study, funded by the U.S. Agency for Healthcare Research and Quality. Though overprescribing of antibiotics is already a high-profile issue, the study is thought to be the first to look at overall outpatient antibiotic prescribing. It analyzed more than a half million prescriptions from 514 outpatient clinics.