Tracking the Uptake of Evidence

BACKGROUND: Advances in clinical research methods have led to prospective randomized controlled (level 1) clinical studies evaluating diagnostic modalities resulting in a paradigm shift in the literature for diagnosing deep vein thrombosis (DVT) and pulmonary embolism (PE). To assess whether these advances correlate with clinical practice, we analyzed 21-year trends in diagnostic testing for patients with venous thromboembolism. METHODS: We used discharge data from the National Hospital Discharge Survey (1979-1999) to determine DVT and PE cases annually. Procedure fields were screened to determine patients who had DVT or PE or who underwent venography, arteriography of the pulmonary arteries, pulmonary scintigraphy, or DVT ultrasonic scanning. Searching EMBASE, MEDLINE, and the American Thoracic Society guidelines, a literature-based time line of level 1 studies was derived and juxtaposed against trends and procedure use. RESULTS: Improved diagnostic tests resulted in diagnostic changes in patients with suspected venous thromboembolism. These observed changes correlated over time in subsequent years with level 1 studies. Diagnostic DVT approaches showed an initial marked increased use of venography followed by a rapid decline that coincided with increased use of Doppler ultrasonography. Diagnostic approaches to PE were characterized by initial marked increases in lung scanning followed by a rapid decline as use of ultrasonography considerably increased and pulmonary angiography modestly increased. CONCLUSIONS: Diagnostic approaches to DVT and PE have changed markedly during the past 2 decades, in temporal harmony with the evolving literature. Change in clinical practice occurs over years, and long-term follow-up is required to capture this change.