Risk Factors for Death in 632 Patients with Sickle Cell Disease in the United States and United Kingdom

BACKGROUND The role of pulmonary hypertension as a cause of mortality in sickle cell disease (SCD) is controversial. METHODS AND RESULTS We evaluated the relationship between an elevated estimated pulmonary artery systolic pressure and mortality in patients with SCD. We followed patients from the walk-PHaSST screening cohort for a median of 29 months. A tricuspid regurgitation velocity (TRV)≥ 3.0 m/s cuttof, which has a 67-75% positive predictive value for mean pulmonary artery pressure ≥ 25 mm Hg was used. Among 572 subjects, 11.2% had TRV ≥ 3.0 m/sec. Among 582 with a measured NT-proBNP, 24.1% had values ≥ 160 pg/mL. Of 22 deaths during follow-up, 50% had a TRV ≥ 3.0 m/sec. At 24 months the cumulative survival was 83% with TRV ≥ 3.0 m/sec and 98% with TRV < 3.0 m/sec (p < 0.0001). The hazard ratios for death were 11.1 (95% CI 4.1-30.1; p < 0.0001) for TRV ≥ 3.0 m/sec, 4.6 (1.8-11.3; p = 0.001) for NT-proBNP ≥ 160 pg/mL, and 14.9 (5.5-39.9; p < 0.0001) for both TRV ≥ 3.0 m/sec and NT-proBNP ≥ 160 pg/mL. Age > 47 years, male gender, chronic transfusions, WHO class III-IV, increased hemolytic markers, ferritin and creatinine were also associated with increased risk of death. CONCLUSIONS A TRV ≥ 3.0 m/sec occurs in approximately 10% of individuals and has the highest risk for death of any measured variable. The study is registered in ClinicalTrials.gov with identifier: NCT00492531.