Original Study Delirium During Acute Illness in Nursing Home Residents Kenneth Boockvar MD, MS a, b, c, *, Daniel Signor BS a , Ravishankar Ramaswamy MD c , William Hung MD, MPH a, c a James J. Peters VA Medical Center, Bronx, NY b Jewish Home Lifecare, New York, NY c Icahn School of Medicine at Mount Sinai, New York, NY Keywords: Nursing homes delirium nosocomial infection activities of daily living abstract Objectives: To ascertain the incidence of delirium during acute illness in nursing home residents, describe the timing of delirium after acute illness onset, describe risk factors for delirium, and explore the rela- tionship between delirium and complications of acute illness. Design: Prospective observational cohort study. Setting: Three nursing homes in metropolitan New York. Participants: Individuals who were expected to remain in the nursing home for at least 2 months, who, as part of a parent study, were receiving opioids, antidepressants, or antipsychotics on a routine basis, and who did not have an acute medical illness at the time of screening. Acute illness surveillance was per- formed twice weekly through communication with nursing home nursing staff and medical providers using established clinical criteria for incipient cases. Measurements: We followed patients for 14 days after illness onset, and, if applicable, an additional 14 days each after hospital admission and hospital discharge. Delirium was assessed 3 times weekly using the Confusion Assessment Method (CAM). Physical function decline was calculated using change in the Minimum Data Set Activities of Daily Living Scale (MDS-ADL) and cognitive function decline using change in the Minimum Data Set Cognitive performance scale (MDS-CPS). Falls were ascertained by record review. Results: Among 136 nursing home patients followed for a mean of 11.7 months, 78 experienced 232 acute illnesses, of which 162 (71%) were managed in the nursing home. The most common diagnoses were urinary tract infection (20%), cellulitis (15%), and lower respiratory tract infection (9%). Subjects expe- rienced delirium during 41 (17.7%) of 232 acute illnesses. Female sex was associated with a greater risk of delirium (odds ratio 2.59; 95% confidence interval [CI] 1.04e6.43) but there were no other risk factors identified. Delirium was a risk factor for cognitive function decline (odds ratio 4.59; 95% CI 1.99e10.59; P ¼ .0004), but not ADL function decline or falling. Conclusion: Delirium occurred frequently as a complication of acute illness in the nursing home, and was a risk factor for cognitive function decline. This finding supports the rationale to target individuals at the onset of an acute medical problem in the design of interventions to prevent delirium in the nursing home setting. Published by Elsevier Inc. on behalf of the American Medical Directors Association, Inc. Approximately one-third of older adults hospitalized with acute medical problems experience delirium. 1e3 Hospitalized older adults who experience delirium are more likely to experience function decline, prolonged length of stay, and death, as compared with those without delirium. 4,5 Like hospitalized older adults, nursing home residents have acute medical problems that are managed in the nursing home and could cause delirium, including respiratory infections, urinary tract infections, and exacerbations of heart and lung disease. 6e8 Because there is also a high prevalence of risk factors for delirium 9e11 in long-term nursing home residents, including cognitive impairment, immobility, sensory impairment, and medication use, delirium would be anticipated to be a common complication of acute illness in nursing home patients, and would be anticipated to be associated with adverse events such as falls and functional decline. To date, studies of the prevalence of delirium and delirium symptoms in nursing home residents have yielded a wide range of This study was funded by VA Health Services Research and Development Grants ARCD 03-027-1 and REA 08-260. Dr. Boockvar was supported by the Greenwall Foundation. The authors declare no conflicts of interest. * Address correspondence to Kenneth Boockvar, MD, MS, Jewish Home Lifecare, 120 West 106th Street, New York, NY 10025. E-mail address: kenneth.boockvar@mssm.edu (K. Boockvar). JAMDA journal homepage: www.jamda.com 1525-8610/$ - see front matter Published by Elsevier Inc. on behalf of the American Medical Directors Association, Inc. http://dx.doi.org/10.1016/j.jamda.2013.06.004 JAMDA 14 (2013) 656e660