NPPB and osteonecrosis: Combined results show that leg ulcers (OR 3.27, 95% CI 1.92-5.53, P<0.0001), priapism (OR 2.62, 95% CI 1.13-6.90, P = 0.03) and pulmonary hypertension defined by NTproBNP (OR 4.32, 95% CI 2.12-8.60, P<0.0001) were significantly more prevalent with chronic hyper-hemolysis, while osteonecrosis (OR 0.32, 95% CI 0.19-0.54, P<0.0001) and severe pain episodes (OR 0.23, 95% CI 0.09-0.55, P = 0.0004) were less prevalent (Figure 4C).