The relative impact of inadequate primary and secondary prevention on cardiovascular mortality in the United States

Background and Purpose - We developed a model to estimate the costs incurred by ineffective primary and secondary prevention in terms of excess cardiovascular disease (CVD) mortality in a nationally representative sample of the US population. Methods - Cox proportional hazards analyses were used to examine the effect of inadequate risk factor control on the incidence of fatal stroke and myocardial infarction (MI) during a follow-up period of 13.4±3.6 years after adjusting for differences in age, gender, and ethnicity in a national cohort of 9252 adults who participated in the Second National Health and Nutrition Examination Survey (NHANES) Mortality Follow-up Study. Inadequate risk factor modification was defined by presence of either blood pressure >140/90 mm Hg, serum cholesterol >200 mg/dL, or active cigarette smoking. Using the data from 4115 adults screened in the NHANES 1999 to 2000, population attributable risk (PAR) percent and associated cost incurred (expressed as proportion of total 1-year cost incurred for CVD mortality in year 2001) was estimated. Results - CVD mortality risk increased in a stepwise manner for persons with no previous MI or stroke and ≥2 inadequately controlled risk factors (2x); and previous history of MI and stroke and adequately controlled risk factors (2.6x), 1 inadequately controlled risk factor (4.3x), and >2 inadequately controlled risk factors (5.7x). The PAR was 14% (estimated cost incurred $13.2 billion) among persons with >2 inadequately controlled risk factors without previous MI or stroke (estimated 17% of total US population). Among persons with previous MI or stroke, the PAR was 7% (cost incurred $6.2 billion) and 8% (cost incurred $7.4 billion) for 1 inadequately controlled risk factor and ≥2 inadequately controlled risk factors, respectively. An excess of cost of $13.6 billion was spent on 4% of the total population (persons with inadequate secondary prevention). Conclusions - The model demonstrates the differential risk of mortality from inadequately controlled cardiovascular risk factors in primary and secondary prevention settings. The large financial cost incurred by inadequate primary and secondary prevention justifies intensive efforts directed toward detection and treatment of cardiovascular risk factors.