Better Assessment of Illness Study (BASIL) II for Delirium Severity: Study Design, Variables, and Methods.

PurposeDelirium is a common yet preventable complication of hospitalization, surgery and illness that is associated with poor outcomes. Older adults with Alzheimer's Disease and Related Dementias (ADRD) are especially vulnerable to delirium and experience greater delirium severity, yet no existing assessment tool is specifically designed to evaluate this vulnerable population. This study will validate two new delirium severity instruments, the Delirium Severity (DEL-S) rating for all older adults and the Delirium Severity Rating in ADRD (DEL-S-AD) for patients with dementia.Design/Setting and ParticipantsThe Better ASsessment of ILlness II (BASIL II) study is an innovative prospective cohort study that measures cognitive function, delirium, delirium severity, demographics, clinical and functional variables and clinical outcomes. Participants include older adults from 3 unique yet complementary clinical sites: medical inpatients, elective surgery inpatients, or skilled nursing facility residents.MethodsPerformance of DEL-S and DEL-S-AD items in older adults with cognition ranging from no impairment to moderate impairment will be determined. Analyses will include psychometric characteristics of DEL-S and DEL-S-AD items, harmonization of the two scales and validation against reference standard diagnoses.Conclusions and ImplicationsResults from this study will help accurately measure delirium severity, a critically important, graded outcome. The DEL-S-AD instrument holds broad applications in persons with and without ADRD to monitor delirium severity in clinical settings, and as an outcome measure in future clinical treatment trials and pathophysiologic studies. Ultimately, the DEL-S and DEL-S-AD have the potential to improve health care for the vulnerable, growing population of older adults with cognitive impairment worldwide.