Aggressiveness of Intensive Care Use Among Patients with Lung Cancer in the Surveillance, Epidemiology, and End Results-Medicare Registry

Background: Approximately 65% of elderly patients with lung cancer who are admitted to the ICU will die within 6 months. Efforts to improve end-of-life care for this population must first understand the patient factors that underlie admission to the ICU.

Methods: We performed a retrospective cohort study examining all fee-for-service inpatient claims in the Surveillance, Epidemiology, and End Results (SEER)-Medicare registry for elderly patients (aged > 65 years) who had received a diagnosis of lung cancer between 1992 and 2005 and who were hospitalized for reasons other than resection of their lung cancer. We calculated yearly rates of ICU admission per 1,000 hospitalizations via room and board codes or International Classification of Diseases, Ninth Revision, Clinical Modification and diagnosis-related group codes for mechanical ventilation, stratified the rates by receipt of mechanical ventilation and ICU type (medical/surgical/cardiac vs intermediate), and compared these rates over time.

Results: A total of 175,756 patients with lung cancer in SEER were hospitalized for a reason other than surgical resection of their tumor during the study period, 49,373 (28%) of whom had at least one ICU stay. The rate of ICU admissions per 1,000 hospitalizations increased over the study period from 140.7 in 1992 to 201.7 in 2005 (P < .001). The majority of the increase in ICU admissions (per 1,000 hospitalizations) between 1992 and 2005 occurred among patients who were not mechanically ventilated (118.2 to 173.3, P < .001) and among those who were in intermediate ICUs (20.0 to 61.9, P < .001), but increased only moderately in medical/surgical/cardiac units (120.7 to 139.9, P < .001).

Conclusions: ICU admission for patients with lung cancer increased over time, mostly among patients without mechanical ventilation who were largely cared for in intermediate ICUs.