Background: Computed tomographic pulmonary angiography (CTPA) may improve detection of life-threatening pulmonary embolism (PE), but this sensitive test may have a downside: overdiagnosis and overtreatment (finding clinically unimportant emboli and exposing patients to harms from unnecessary treatment).
Methods: To assess the impact of CTPA on national PE incidence, mortality, and treatment complications, we conducted a time trend analysis using the Nationwide Inpatient Sample and Multiple Cause-of-Death databases. We compared age-adjusted incidence, mortality, and treatment complications (in-hospital gastrointestinal tract or intracranial hemorrhage or secondary thrombocytopenia) of PE among US adults before (1993-1998) and after (1998-2006) CTPA was introduced.
Results: Pulmonary embolism incidence was unchanged before CTPA (P = .64) but increased substantially after CTPA (81% increase, from 62.1 to 112.3 per 100,000; P < .001). Pulmonary embolism mortality decreased during both periods: more so before CTPA (8% reduction, from 13.4 to 12.3 per 100,000; P < .001) than after (3% reduction, from 12.3 to 11.9 per 100,000; P = .02). Case fatality improved slightly before (8% decrease, from 13.2% to 12.1%; P = .02) and substantially after CTPA (36% decrease, from 12.1% to 7.8%; P < .001). Meanwhile, CTPA was associated with an increase in presumed complications of anticoagulation for PE: before CTPA, the complication rate was stable (P = .24), but after it increased by 71% (from 3.1 to 5.3 per 100,000; P < .001).
Conclusions: The introduction of CTPA was associated with changes consistent with overdiagnosis: rising incidence, minimal change in mortality, and lower case fatality. Better technology allows us to diagnose more emboli, but to minimize harms of overdiagnosis we must learn which ones matter.