Delirium, cancer and heart failure diagnoses, age, immobility, serum albumin levels lower than 3.3 mg/dL at admission and serum creatinine levels equal to or higher than 1.3 mg/dL at admission were identified in this study as independent factors related to higher mortality in hospitalized older patients.
The continuous growth of the geriatric population in recent decades has led to an increasing number of acute hospitalizations.19
For many older patients, acute clinical conditions that demand hospital care are life-changing events that often result in functional decline, institutionalization, or even death. Such unfavorable outcomes are noticed not only during the hospital stay, but also in the year following discharge.19,20
Few authors have explored the many factors that contribute to mortality in the elderly during hospitalization. A multicenter study carried out in Europe that included 1,626 patients at least 65 years old verified that death was correlated both to functional and cognitive impairment and with the male gender.19
A recent systematic review from the same group indicated that functional decline, illness severity, cognitive impairment, comorbidity scores, polypharmacy, age and male gender were all associated with higher mortality.5
Physical function was a particularly strong mortality predictor, and a consistent correlation has been established by many studies.4,21,22
One of the main contributions of this study is to confirm the importance of delirium as a factor associated with death among elderly in-patients. Delirium has a great impact on the health of older patients. Those who are affected not only experience prolonged hospitalizations and functional decline,23
but may also have persisting signs of delirium for 12 months or longer after discharge. This is particularly prevalent in those diagnosed with dementia.24
Delirium was diagnosed in 32.6% of the individuals included in this study. It has been reported that up to 70% of patients older than 70 years arrive at the emergency room with some level of cognitive impairment, and that up to 25% are diagnosed with delirium.25
Another study verified that 24% of community-originating patients and 64% of institutionalized patients were diagnosed with delirium on hospital arrival.26
Additionally, delirium is one of the earliest clinical manifestations of older patients’ acute ailments and has been associated with increased morbidity and mortality.27
The mortality associated with delirium is high. In agreement with previously reported data, we observed that 34.8% of our delirium-diagnosed patients died during hospitalization. According to the literature, older patients who develop delirium after admission have a 22% to 76% risk of dying before hospital discharge.27
It is also estimated that after discharge, the 1-month and 6-month month mortality rates are 14% and 22%, respectively; approximately twice that of patients without delirium.28
The concomitant presence of dementia and severe physical illness probably influenced these results, but prospective observational studies that adjusted for such confounding factors still found that delirium was an independent marker of mortality at 6 or 12 months after hospitalization.29–31
The importance this diagnosis as an indicator of poor prognosis and increased length of stay demands an assessment for delirium in geriatric patients who are agitated or have acutely impaired cognitive functions.32,33
Additionally, the implementation of preventive measures and daily cognitive evaluations is also crucial to diminish the impact of delirium in patient outcomes.
In agreement with previous studies, the importance of functional status in the prediction of mortality was shown. A higher prevalence of immobility was observed among the patients who died, and, after multivariate analysis, this diagnosis was confirmed as an independent factor associated with higher mortality. Similar results were reported by another study that, after analyzing 353 elderly patients, verified that functional impairment at admission was strongly correlated to death.21
The comparison of immobility with other widely employed functionality status measures is necessary. Further studies using the Functional Independence Measure (FIM)34
and the Katz functionality scale35
are being conducted to investigate this issue.
Our results confirmed the association between higher mortality rates and malnutrition, a common condition among hospitalized older patients. Poor nutritional condition has already been established as an independent predictor of bad prognosis at admission, and this association is not exclusively due to illness severity, comorbidities, or functional impairment.36
More specifically, diminished levels of serum albumin, besides implying higher in-hospital mortality levels,37
are also associated with death in the general elderly population.33
In agreement with our findings, other authors37
have described higher in-hospital mortality among geriatric patients with albumin levels lower than 3.3 mg/dL at admission. Additionally, other researchers have documented a correlation between mortality at one year following discharge and albumin levels lower than 3.5 mg/dL at admission.12
This study also showed that neoplastic disease diagnoses, whether already established at admission or given later during hospital stay, were associated with death. It is important to note that many of the patients diagnosed with cancer had metastases at admission, which could explain the elevated mortality rate in that population.
Having a history of heart failure was also associated with higher mortality. It is known that patients aged 70 years and over who suffer from heart failure have a poorer prognosis, with a greater number of them dying within a year, when compared to younger individuals.38
Comorbidities are a key factor in mortality prediction among older in-patients, and heart failure has been described and corroborated by our study as one of the strongest influences on these individuals’ outcomes.38
The evaluation of clinical severity by physiological criteria is essential when predicting the mortality of older hospitalized individuals. Our study verified that creatinine level at admission is an independent mortality predictor in this population.16
On the other hand, even though age was identified in our work and in other studies as an independent factor associated with death, other authors suggest that it is not such a significant predictor after clinical and functional status are considered.5
A limitation of this study is that the impact of dementia diagnoses in hospitalized elderly mortality was not evaluated. Cognitive impairment has already been identified as a predictor of immediate and late mortality among geriatric patients,4,12
and its role should be studied more carefully in the future.