The Authors Reply.

We appreciate your interest in our paper and are thankful for taking the time to express your opinions. We would also like to thank you for the opportunity to clarify aspects of our methodology in relation to concerns on diagnostic criteria of the study patients and further express our opinions on the issue of elderly patients’ intensive care unit (ICU) care.

As for the low proportion of sepsis, the article has a limitation. The Materials and Method section states that “The ICU patients with diagnoses associated with ICU mortality were classified into 10 subcategories. Diagnoses were sorted according to main 10th revision of the International Statistical Classification of Diseases (ICD-10) codes of the patients.” Due to large number of study patients (10,366), checking whether each patient had been diagnosed of sepsis according to strict clinical definitions was impossible, and it is possible that the patients in other disease categories would have been treated for sepsis; for example, sepsis originated from pneumonia, hepatobiliary infection, etc. For future studies, data collection by reviewing individual patient’s medical charts or well-designed prospective studies could overcome the limitation mentioned above.

The very elderly patients have high risk of death for critical illness, when compared to younger age groups [1]. The elderly patients have a higher prevalence of chronic illnesses and an age-related decrease of physical ability [2]. Age of the patients is a significant factor when deciding whether patients should undergo active or palliative treatment. The author has well pointed out that aggressive ICU care for very elderly patients could not be clinically beneficial and concurs heavy economic burdens for patients’ families.

A study in Korea showed that for the elderly, the proportion of patients who had specified “do not resuscitate” is higher than younger age groups [3]. In recent publications from JAMA, Guidet et al. [4] report the results of ICE-CUB 2 study. Patients aged 75 years or more were randomized to usual care hospitals and intervention hospital group, in which the study patients were more actively admitted to ICUs when compared to the counterparts. Paradoxically, even though admission rate was two times higher, intervention group showed no clinical benefit and in-hospital mortality was even higher.

On the other hand, many studies also support ICU care for the elderly patients. A study from the Netherlands showed that both short-term and long-term risk-adjusted mortality decreased significantly in both very elderly ICU patients and patients aged less than 80 years during the period of 2008–2014 [5]. Another study in Korea showed that ICU and in-hospital mortalities were not significantly different for very elderly critically ill patients compared to the younger patients [6]. For these reasons, setting age of 80 years as a cutoff for receiving active ICU care could create other problems such as a considerable number of very elderly patients who could be recovered by active ICU care, missing opportunity of treatment. When deciding whether patients should undergo active ICU care, the age of patients should be considered in conjunction to other important factors such as wills of the patient and family to continue intensive treatment, reversibility of the disease and underlying comorbidities.

In conclusion, we agree that medical care for very elderly patients requires different clinical approaches compared to their younger counterparts. Before ICU care of very elderly patients, physicians should carefully consider various patient-related factors in the decision of aggressive versus palliative care, for optimal results.