A first-of-its-kind study looks beyond Medicare readmission rates to determine causes of short-term readmissions of patients across the spectrum of age and insurance types. Researchers found while Medicare patients account for more than half of all readmissions, readmission rates of non-Medicare patients were still significant and costly. Psychiatric disease and substance abuse were the most common diagnoses leading to readmission among non-elderly patients, highlighting the need for targeted interventions.