In a British study assessing the incidence and cost of medication harm in older adults following hospital discharge, 37% of participants experienced medication-related harm (556 events per 1000 discharges), of which 336 (81%) cases were serious and 214 (52%) potentially preventable. Four participants died as a result of the effects of medications. The most common MRH events were
gastrointestinal (25%) or neurological (18%). Opiates, antibiotics and benzodiazepines were found to be the riskiest of medications. The incidence of MRH-associated hospital readmission was 78 per 1000 discharges. More about the substantial problems and even more substantial costs here: https://bpspubs.onlinelibrary.wiley.com/doi/pdf/10.1111/bcp.13613
