Introduction: Stroke death rates have declined nationally, but less in men and non-Hispanic Blacks. We quantified case-fatality and risk factor trend contributions to non-Hispanic Black and non-Hispanic White 1999-2012 stroke mortality trends.
Methods: The CVD Policy Model is a computer simulation of heart disease and stroke incidence, prevalence, and mortality in US adults ≥ 35 years old. We modeled mean systolic blood pressure (SBP), low-density lipoprotein (LDL), and body mass index (BMI), prevalence of diabetes and smoking, and case fatality for 1999-2002, 2003-06, and 2007-12 by sex and race (NHANES; NHDS) to predict stroke mortality trends and these predictions were compared with observed data (CDC Wonder; ICD-10 I60-69). We then simulated the effects of isolated risk factors on stroke mortality in younger (age 35-64 years) and older (age 65-84 years) men and women.
Results: Model predictions mirrored observed trends for stroke mortality in Whites (men: predicted -27.0% v. observed -29.2%; women: -34.8% v. -33.3%) and Blacks (men: -23.8% v. -22.2%; women: -31.0% v. -30.0%). Case fatality was the main contributor to the observed decrease in stroke mortality (approximately -25%) but did not explain differences between race groups. Combined risk factor trends contributed to decreased mortality in women (-12.8% in Whites; -8.7% in Blacks), but not men. Decreased mean SBP contributed in all women (-10.7% to -12.6%, depending on age/race) and older men (-4.0%), but not young men. Increased diabetes prevalence offset improvements in stroke mortality in older White men (+2.5%), younger Blacks (men: +4.0, women: +1.5%) and, to a larger degree, older Blacks (men: +9.9%, women: +5.6% ).
Conclusions: Reduced case fatality was the strongest driver of decreased stroke mortality from 1999-2012 overall, while risk factor trends explained gender and race differences. Targeting high blood pressure in young adult men and preventing diabetes at all ages could further decrease stroke mortality and reduce racial differences. Blacks would benefit most from more aggressive stroke risk factor control.