Population estimates of sickle cell disease in the U.S.

BACKGROUND The number of individuals with sickle cell disease (SCD) in the U.S. is unknown. Determination of burden of disease, healthcare issues, and policies is best served by representative estimations of the SCD population. PURPOSE To update SCD population estimates by using recent U.S. Census and birth-cohort SCD prevalence for at-risk populations as available through the centralized reporting of universal newborn screening for hemoglobinopathies, with an effort to demonstrate the potential effect of early mortality. METHODS National and state SCD populations were estimated based on the 2008 U.S. Census, using total, African-American, and Hispanic birth-cohort disease prevalence derived from the National Newborn Screening Information System. Estimates were corrected for early mortality for sickle cell anemia using data from the CDC's Compressed Mortality Report and published patient-cohort survival information. RESULTS National SCD population estimates ranged from 104,000 to 138,900, based on birth-cohort disease prevalence, but from 72,000 to 98,000 when corrected for early mortality. Several limitations were noted in the available data, particularly for SCD mortality in adults. CONCLUSIONS The number of individuals with SCD in the U.S. may approach 100,000, even when accounting for the effect of early mortality on estimations. A paucity of high-quality data limits appropriate estimation. State-to-state variability may preclude application of state-specific information to other states or to the nation as a whole. Standardized collection and centralized reporting, a surveillance system, will be necessary to assess the size and composition of the U.S. SCD population.