Number of ambulatory medical care visits with diagnosis of VTE (ICD-9-CM codes 415.1, 451.11, 451.19, 451.2, 451.81, 451.9, 453.1, 453.4, 453.40, 453.41, 453.42, 453.9, 671.3 [0,1,3], 671.4 [0,4], 997.2), in at least one of the three diagnosis fields, during the year of interest, among adults 18 years or older
Venous thromboembolism (ICD-9-CM codes, as stated in the definition of numerator) listed in any of the three diagnoses fields, in the mentioned datasets is considered a diagnosis of VTE.
FOR SINGLE DATA YEARS: Ambulatory care visit rates are calculated using the July 1 estimates of the civilian noninstitutionalized population from the Vintage matching the data year for the postcensal period based on the 2000 census. For example, July 1, 2007 civilian noninstitutionalized population estimates from Vintage 2007 are used as the denominator for 2007 rates. Rates for 2010 are also calculated using the July 1 estimates based on the 2000 census.