Priapism in patients with hemolytic disorders: a nationwide retrospective cohort study

Priapism is a persistent, painful erection, which can lead to permanent penile damage and reduced quality of life. Patients with sickle cell disease have an increased risk of priapism which has been related to chronic hemolysis. This study investigates the prevalence of priapism in all major hereditary and acquired forms of hemolytic disorders. Patients with hemolytic disorders were identified in the nationwide Danish Hemolysis Cohort. Each patient was age-sex-matched with 50 comparisons from the general population without hemolysis. We identified the episodes of hospital-registered priapism events for both patients with hemolysis disorders and comparisons in the Danish National Patient Register between 1977 and 2016. We identified 4181 male patients with hemolytic disorders and 205,994 male comparisons, with 2,294,027 person-years of total observation time. Totally, 101 episodes of priapism occurred during follow-up period. Six episodes of priapism were recorded in three patients with a hemolytic disorder, all affected by sickle cell disease. Two of these patients had verified genotype HbSS. The incidence rate for first priapism in sickle cell disease was 432.8 per 100,000 person-years [95% CI: 139.6; 1341.8] versus 0.84 per 100,000 person-years [95% CI 0.54; 1.32] in comparisons. Using a large nationwide cohort, we found that only sickle cell disease is associated with priapism among patients with hemolytic disorders. The incidence rate of priapism in patients with sickle cell disease was lower than previously reported.