The future of delirium research: promising but still room for improvement

Abstract

Aging Clin Exp Res, Vol. 19, No. 3 169 Delirium is a common and important issue in medical care of older persons; during the last few decades, increased interest in delirium research has led to major advances in our understanding of delirium in different patient populations and settings. A Medline search for delirium as a keyword identified only 57 articles in 1990; that number grew to 138 in 2000 and 198 for 2006, reflecting growth in delirium research. Patient populations under study have evolved from elderly medical patients initially to any adult surgical, or critically ill, or post-hospitalization nursing home patient. Study methods for delirium research have also evolved. Beginning with early descriptive epidemiological prospective cohort studies, pathophysiological studies came next, and now we see randomized controlled trials. Pharmacological and non-pharmacological interventions are being studied as well. Our understanding of risk factors for delirium continues to expand (1). Predictive models for delirium show that older, frail persons with higher severity of illness, co-morbid conditions, and preexisting cognitive impairment are much more likely to become delirious during hospitalization or surgery. Additionally, the way we manage these patients in the hospital may predispose them to delirium. Restraints, psychoactive and anticholinergic medications, restricted mobility, and poor sleep and nutrition contribute significantly to the risk of delirium. Prevention strategies, largely as multi-factorial models, have been shown to be effective in reducing the rate and duration of delirium in medical and surgical patients. However, once delirium occurs, management remains difficult. The medical community has also come to realize that delirium is worth preventing; multiple studies have shown that delirium is independently associated with worse outcomes, both in hospital and long-term. Cognitive changes The future of delirium research: promising but still room for improvement