Survival analysis of elderly patients in Intensive Care Units

Abstract

Objective: Conduct a survival analysis of elderly patients hospitalized in an intensive care unit (ICU), identifying the predictors of mortality among this age group. Methods: A retrospective cohort study was performed with data from the medical records of 457 elderly patients hospitalized in an ICU located in the city of Natal in Brazil. Survival functions were estimated using the Kaplan-Meier estimator, and the Log-rank test was used for comparisons. In addition, a multiple Cox proportional hazards model was constructed to identify the independent effects of the predictors of survival. Results: It was found that the survival of elderly ICU patients declined due to factors such as increased hospitalization time, advancing years, unmarried (including common-lawmarriage) status, the presence of shock, pneumonia, septicaemia, fractures, a reduced state of consciousness, hospitalization for clinical reasons, being bedridden prior to hospitalization, fever, bradycardia, hypotension, cardiac arrest and the need for mechanical ventilation. The multiple Cox proportional hazards model revealed that variables such as shock, longevity, bradycardia, fractures, fever, hospitalization in the public healthcare system and admission for clinical reasons remained significant as predictors of reduced survival in intensive care units. Conclusions: The survival rates of elderly persons in an ICU in the city of Natal in Brazil were affected by demographic and clinical predictors, and those related to the type of hospitalization and the health care network. This shows that any initiative aimed at increasing the survival of elderly ICU patients must look at individual and social issues and factors related to the health care network.

Perfil clínico de longevos em uma unidade de terapia intensiva

“…In one study, it was identified that acute clinical injuries and age over 80 years are associated with mortality in survival studies with follow-up of less than 30 days, and that situations such as lower consciousness level, use of mechanical ventilation and respiratory diseases are factors that worsen this outcome. (11) The mortality of the long-living patients in this study was high (51.6%), and may also be related to the high rates of origin from the emergency unit, with prolonged hospitalization. A large part (24.6%) remained hospitalized for between 11 and 20 days, a longer period when compared to other studies.…”

“…(10) The presence and number of comorbidities found was not related to the outcome death, which was also observed in another study conducted in Rio Grande do Norte with elderly people hospitalized in the ICU. (11) In that study, it was observed that comorbidities and chronic diseases were not related to the survival of the elderly in survival studies with less than 30 days of follow-up; the presence of comorbidities was associated with unfavorable outcomes in the hospitalized elderly though when the follow-up was longer than 30 days.…”

“…(2) In addition, in another study, sepsis had an impact on the mortality of elderly patients hospitalized at an ICU, regardless of the length of hospital stay. (11) Hence, it is observed that the clinical demands of the long-living patients in the ICU stand out in comparison to the surgical demands, possibly due to the worsening of chronic problems. In one study, it was identified that acute clinical injuries and age over 80 years are associated with mortality in survival studies with follow-up of less than 30 days, and that situations such as lower consciousness level, use of mechanical ventilation and respiratory diseases are factors that worsen this outcome.…”

“…A large part (24.6%) remained hospitalized for between 11 and 20 days, a longer period when compared to other studies. (11) A study that investigated the factors related to the occurrence of adverse events in critically ill elderly people, although it did not relate these to the long-living age group, identified an average of 5.06 days of ICU hospitalization in those who did not suffer adverse events, against 10.62 days in those who did; for those who presented moderate to severe cases of these events, the mortality rate was 38.3%. (4) In this study, even the long-living patients mostly presented a good general health condition at the time of admission, with intact skin, diuresis and spontaneous ventilation, preserved lucidity and ori-entation; the length of hospital stay was significant, making them more fragile, dependent and vulnerable to the unfavorable outcome.…”

Adaptação de longevos no domicílio após alta da unidade intensiva

“…5 It is pointed out that the elderly have a longer hospital stay when compared to other age groups and a shorter significant survival, mainly due to senescence-related weaknesses added to the disease process. [6][7][8] It is known that, at the time of hospital discharge, the elderly may present injuries that did not have in their pre-hospitalization state, such as loss and reduction of functional capacity, and lower tolerance to physical activity. It is noteworthy that functional impairment prior to ICU admission may represent a determining condition for an unfavorable outcome in the elderly.…”