Survival estimates of adults with sickle cell disease (SCD) in highincome countries are limited because of the absence of prospective cohorts of young adolescents followed to and through adulthood. Recently, Gardner et al described a cohort of 712 adults with SCD (16-80 years of age) at King’s College Hospital (London, UK) from 2004 to 2013 that included 5268 patientyears of observation, and the median observation per patient was 8 years. 1 The estimated median age of survival was 67 years for 450 adults with HbSS/HbSb0, an age that is significantly greater than that observed in a similar study in the United States reporting a median survival of 44.7 years for 132 adults with HbSS/HbSb0/HbSD. 2

To address whether the higher median survival of adults with SCD living in London compared with adults with SCD living in the United States was related to statistical methods, and not cohort characteristics, we conducted a pooled analysis from 2 academic SCD centers in the United States. The median survival was determined for adults with SCD who received medical care at Vanderbilt University Medical Center (VUMC) and the