Trends in case fatality rate in pulmonary embolism according to stability and treatment

Purpose: To determine categories of patients with pulmonary embolism in whom therapy has been reducing or failing to reduce case fatality rate.

Methods: Patients with acute pulmonary embolism were assessed from the Nationwide Inpatient Sample, 1999-2008. Trends of case fatality rates were assessed according to whether patients were stable or unstable and according to treatment within these groups.

Results: In-hospital all-cause case fatality rate among all patients with pulmonary embolism decreased from 16,150 of 136,740 (11.8%) in 1999 to 23,040 of 311,620 (7.4%) in 2008. All-cause case fatality rate decreased 45.0% in stable patients from 14,780 of 133,230 (11.1%) in 1999 to 18,170 of 297,770 (6.1%) in 2008. In unstable patients it decreased only 9.7% from 1,370 of 3,510 (39.0%) in 1999 to 4,870 of 13,850 (35.2%) in 2008. Only 72,230 of 2,110,320 (3.4%) patients with acute pulmonary embolism were unstable. Among unstable patients who received thrombolytic therapy, all-cause mortality did not change from 1999-2008. Among unstable patients treated only with anticoagulants and/or a vena cava filter, all-cause case fatality rate decreased 23.6% from 1,110 of 2,080 (53.4%) in 1999 to 4,290 of 10,530 (40.7%) in 2008, but remained higher than in those treated with thrombolytic agents. Case fatality rates attributable to pulmonary embolism were lower than all-cause case fatality rate, but showed similar trends.

Conclusions: The decreasing all-cause case fatality rate and case fatality rate attributable to pulmonary embolism from 1999-2008 resulted primarily from a decreasing case fatality rate in stable patients. There was no reduction of case fatality rate in unstable patients who received thrombolytic therapy, although case fatality rate was relatively low with thrombolytic therapy plus a vena cava filter. Most unstable patients, however, failed to receive this combination of therapy.