Background: Atypical disease presentations, such as delirium, are asso
ciated with adverse health outcomes. They are also markers of frailty
in elderly people, which is itself associated with adverse hospital ou
tcomes. We investigated the relationship between frailty and atypical
disease presentation in predicting adverse hospital outcomes and compl
ications of the hospital course of elderly patients admitted to genera
l medical services. Methods: We conducted a cohort study in a large (8
00 beds) tertiary care university hospital. The prevalence of atypical
disease presentations and the incidence of adverse hospital outcomes
(death, nursing home admission, prolonged hospital stay, and failure t
o regain premorbid functional status) were studied in previously well
and previously frail elderly patients. Results: Patients were classifi
ed as being well or frail on the basis of the premorbid Barthel Index
(well, score of greater than or equal to 95 [n=76]; frail, score of <9
5 [n=117]). Frail elderly were older (80 vs 76 years), more often fema
le (62% vs 46%), and less likely to be community dwelling (89% vs 99%)
. Atypical disease presentation was more common in the frail elderly (
59% vs 25%; P<.001). Of those who presented atypically, the frail most
often presented with delirium (61%) and the well presented with falls
(37%) and delirium (32%). Of the frail elderly with atypical symptoms
, 60% had adverse hospital outcomes compared with 32% of the well elde
rly who presented typically (P<.05). Logistic regression analysis show
ed that premorbid functional dependence (odds ratio, 2.48; 95% confide
nce interval, 1.17 to 5.22), atypical disease presentation (odds ratio
, 2.37; 95% confidence interval, 1.20 to 4.67), and functional decline
at admission (odds ratio, 5.64; 95% confidence interval, 2.37 to 13.4
4) were all independently predictive of poor hospital outcomes. By con
trast, severity of disease, age, and sex did not confer an increased r
isk of adverse events. Conclusions: Premorbid functional dependency, a
typical disease presentation, and functional decline on admission have
independent impacts on adverse hospital outcomes. Assessment of each
should be incorporated into the routine care of elderly patients.