Delirium, in 405 articles of medical (non-surgical or ICU) inpatients: unproven speed of onset and recovery

PURPOSE: There is agreement in the medical literature that delirium is of sudden or rapid onset. Although the speed of recovery cannot be used for initial diagnosis, recovery speed provides a test of diagnostic criteria. The aim of this study was to determine whether articles on delirium among medical inpatients proved sudden onset and rapid recovery. METHODS: The literature was searched for studies with at least 50 patients on medical or geriatric wards. Excluded were postoperative, critical care, and nursing home studies. Speed of onset was extracted as either the interval between symptom onset and diagnosis or between hospital admission and diagnosis of incident delirium. Mean or median days to recovery from delirium and the scale used to measure recovery were identified. RESULTS: Four-hundred and five articles were analyzed with 789,709 patients. The median article had 220 patients. Onset could only be extracted in 11 articles (2.7%): mean onset was 3.09±2.38 days. Median onset was 3.0 days, which conforms to Diagnostic and Statistical Manual of Mental Disorders (DSM-V). Only 56 of 405 articles (13.8%) reported timing of recovery but mean or median recovery was available in 25 of 405 (6.2%): 6.56±4.80 days. CONCLUSION: Medical delirium articles have failed to establish rapid onset and rapid recovery.