Age associated with risk for death in ICU survivors

A French study found that mortality risk after ICU discharge increased progressively across all age strata, with a sharp increase in those ages 80 years and older, but excess long-term mortality was highest in younger, not elderly, patients.

For elderly patients discharged from an ICU, risk for long-term mortality standardized by age and sex was similar to that of the general population, but it was increased in younger ICU survivors, a recent study found.

Researchers in France used data from the French national health system database to perform a cohort study describing short-term and long-term mortality, defined as up to three years after discharge, by age in adult ICU patients. In-hospital mortality and mortality at three months and three years after discharge were determined for ICU admissions from Jan. 1 to Dec. 31, 2013. The study results were published May 10 by JAMA Network Open.

Overall, 133,966 patients were included in the study, 108,539 of whom were discharged from the hospital alive. Median age of the study cohort was 65 years, and 59.9% were men. Total in-hospital, three-month, and three-year mortality rates were 19.0%, 23.1%, and 39.7%, respectively. Of the patients who were discharged alive, 6.8% died by three months and 25.8% died by three years. Mortality risk increased progressively across all age strata after adjustment for several variables, with a sharp increase seen in those ages 80 years and older. Those in this age group had in-hospital and three-year postdischarge mortality rates of 30.5% and 44.9%, respectively, versus 16.5% and 22.5% in those younger than age 80 years. Total three-year mortality rate was 61.4% in patients who were ages 80 years and older and 35.1% in those younger than age 80 years.

The authors standardized the data by age and sex and found that younger patients had the highest excess mortality in the first year after hospital discharge and that this excess mortality was also present in the second and third year after discharge. This is likely related to the higher life expectancy of younger patients, the authors noted. In elderly patients, meanwhile, the mortality risk in these time frames was close to that of the general population. A strong association was seen between age and long-term mortality, with a 9-, 13- and 20-fold increase in three-year risk in patients ages 80 to 84 years, 85 to 89 years, and 90 years or older, respectively, versus patients younger than age 35 years.

The study was observational and included only French patients who were covered by national health insurance, the authors noted. Among additional limitations, they noted that data on risk behavior and body mass index were not available and that selection bias may have been present. They concluded that the overall three-year survival of patients discharged from ICUs in their study was approximately 60%; that mortality rates increased progressively with age, particularly in those 80 years of age and older; and that age- and sex-standardized mortality ratios were notably high in the study's younger patients immediately after ICU discharge. The last finding, they wrote, suggests that opportunities exist for improvement in this population and time frame.

The authors of an accompanying editorial said that this study, along with previous work, offers data to better inform clinicians' perspectives of critical illness outcomes in elderly patients and, in turn, conversations with patients and families. However, they noted that these data should “inform in broad strokes” and that clinicians should keep in mind that most elderly patients can and do survive a critical illness. “For elderly patients who receive critical care, the focus should be on ensuring that we continue to match care with preferences during the journey, update the goals, and focus on meeting their needs in the post-ICU and posthospital period, including discussions about whether they would want to go through the process again,” the editorialists wrote.