Iron, haemochromatosis genotypes, and risk of infections: a cohort study of 142,188 general population individuals.

It is unclear whether risk of infection is increased in individuals with hereditary haemochromatosis and in individuals with low or high plasma iron, transferrin saturation, or ferritin. Therefore, we tested whether high and low iron, transferrin saturation, and ferritin are associated with risk of infections observationally and genetically through HFE genotypes. We studied 142,188 Danish general population individuals. Iron, transferrin saturation, and ferritin were measured in 136,656, 136,599, and 38,020 individuals, respectively. HFE was genotyped for C282Y and H63D in 132,542 individuals. Median follow-up after study enrolment was 8 years(range:0-38years) for hospital and emergency room admissions with infections(n=20,394 individuals) using the National Patient Register, covering all Danish hospitals. Hazard ratios for any infection were 1.20(95%CI:1.12-1.28) and 1.14(1.07-1.22) in individuals with plasma iron≤5th or ≥95th percentile compared to individuals with iron from 26th-74th percentiles. Findings for transferrin saturation were similar, while infection risk was not increased in individuals with ferritin≤5th or ≥95th percentile. Hazard ratios in C282Y homozygotes versus non-carriers were 1.40(1.16-1.68) for any infection, 1.69(1.05-2.73) for sepsis, and 2.34(1.41-3.90) for death from infectious disease. Risk of infection was increased in C282Y homozygotes with normal plasma iron, transferrin saturation, or ferritin, and in C282Y homozygotes without liver disease, diabetes, and/or heart failure. In summary, low and high plasma iron and transferrin saturation were independently associated with increased infection risk. C282Y homozygotes had increased risk of any infection, sepsis, and death from infections. Even C282Y homozygotes with normal iron, transferrin saturation, or ferritin, not currently recommended for genotyping, had increased infection risk.

Mitapivat versus Placebo for Pyruvate Kinase Deficiency.

BACKGROUND: Pyruvate kinase deficiency is a rare, hereditary, chronic condition that is associated with hemolytic anemia. In a phase 2 study, mitapivat, an oral, first-in-class activator of erythrocyte pyruvate kinase, increased the hemoglobin level in patients with pyruvate kinase deficiency. METHODS: In this global, phase 3, randomized, placebo-controlled trial, we evaluated the efficacy and safety of mitapivat in adults with pyruvate kinase deficiency who were not receiving regular red-cell transfusions. The patients were assigned to receive either mitapivat (5 mg twice daily, with potential escalation to 20 or 50 mg twice daily) or placebo for 24 weeks. The primary end point was a hemoglobin response (an increase from baseline of ≥1.5 g per deciliter in the hemoglobin level) that was sustained at two or more scheduled assessments at weeks 16, 20, and 24. Secondary efficacy end points were the average change from baseline in the hemoglobin level, markers of hemolysis and hematopoiesis, and the change from baseline at week 24 in two pyruvate kinase deficiency-specific patient-reported outcome measures. RESULTS: Sixteen of the 40 patients (40%) in the mitapivat group had a hemoglobin response, as compared with none of the 40 patients in the placebo group (adjusted difference, 39.3 percentage points; 95% confidence interval, 24.1 to 54.6; two-sided P<0.001). Patients who received mitapivat had a greater response than those who received placebo with respect to each secondary end point, including the average change from baseline in the hemoglobin level. The most common adverse events were nausea (in 7 patients [18%] in the mitapivat group and 9 patients [23%] in the placebo group) and headache (in 6 patients [15%] and 13 patients [33%], respectively). Adverse events of grade 3 or higher occurred in 10 patients (25%) who received mitapivat and 5 patients (13%) who received placebo. CONCLUSIONS: In patients with pyruvate kinase deficiency, mitapivat significantly increased the hemoglobin level, decreased hemolysis, and improved patient-reported outcomes. No new safety signals were identified in the patients who received mitapivat. (Funded by Agios Pharmaceuticals; ACTIVATE ClinicalTrials.gov number, NCT03548220.).

Autoimmune hemolytic anemia during pregnancy and puerperium: an international multicenter experience.

Relapsing or occurring de novo autoimmune hemolytic anemia (AIHA) during pregnancy or puerperium is a poorly described condition. Here, we report 45 pregnancies in 33 women evaluated at 12 centers from 1997 to 2022. Among the 20 women diagnosed with AIHA before pregnancy, 10 had a relapse. An additional 13 patients developed de novo AIHA during gestation/puerperium (2 patients had AIHA relapse during a second pregnancy). Among 24 hemolytic events, anemia was uniformly severe (median Hb, 6.4 g/dL; range, 3.1-8.7) and required treatment in all cases (96% steroids ± intravenous immunoglobulin, IVIG, 58% transfusions). Response was achieved in all patients and was complete in 65% of the cases. Antithrombotic prophylaxis was administered to 8 patients (33%). After delivery, rituximab was administered to 4 patients, and cyclosporine was added to 1 patient. The rate of maternal complications, including premature rupture of membranes, placental detachment, and preeclampsia, was 15%. Early miscarriages occurred in 13% of the pregnancies. Fetal adverse events (22% of cases) included respiratory distress, fetal growth restriction, preterm birth, AIHA of the newborn, and 2 perinatal deaths. In conclusion, the occurrence of AIHA does not preclude the ability to carry out a healthy pregnancy, provided close monitoring, prompt therapy, and awareness of potential maternal and fetal complications.

The Danish national haemoglobinopathy screening programme: Report from 16 years of screening in a low-prevalence, non-endemic region.

The Danish national haemoglobinopathy screening programme seeks to determine parental haemoglobinopathy carrier state antenatally. In this retrospective register-based study, we evaluated the 16-year trajectory of this programme, utilising the Danish Red Blood Cell Centre's laboratory database, covering approximately 77% of the Danish population. During the study period, we observed a substantial increase in annual diagnostic examinations performed, from 389 in 2007 to 3030 in 2022. Women constituted 88% of these cases, aligning with the emphasis of the screening programme. Of these, 54% of women of reproductive age (15-40 years) and 10% of women >40 years were specified as pregnant. During our study period, 61 children were born with a severe haemoglobinopathy, out of which 23 children were born from mothers not residing in Denmark during their first trimester thus not included in the screening programme. Prenatal invasive testing was performed for 60 fetuses, identifying 12 with homozygous or compound heterozygous haemoglobinopathy. The Danish haemoglobinopathy screening programme has provided screening, information and reproductive choices for numerous families. During the study period, screening for haemoglobinopathies has been steadily increasing and is expected to continue to increase. Awareness of and adherence to the screening programme is subject of further investigation and optimisation.

Breakthrough COVID-19 in vaccinated patients with hematologic malignancies: results from the EPICOVIDEHA survey.

Limited data are available on breakthrough COVID-19 in patients with hematologic malignancy (HM) after anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination. Adult patients with HM, ≥1 dose of anti-SARS-CoV-2 vaccine, and breakthrough COVID-19 between January 2021 and March 2022 were analyzed. A total of 1548 cases were included, mainly lymphoid malignancies (1181 cases, 76%). After viral sequencing in 753 cases (49%), the Omicron variant was prevalent (517, 68.7%). Most of the patients received ≤2 vaccine doses before COVID-19 (1419, 91%), mostly mRNA-based (1377, 89%). Overall, 906 patients (59%) received COVID-19-specific treatment. After 30-day follow-up from COVID-19 diagnosis, 143 patients (9%) died. The mortality rate in patients with the Omicron variant was 7.9%, comparable to other variants, with a significantly lower 30-day mortality rate than in the prevaccine era (31%). In the univariable analysis, older age (P < .001), active HM (P < .001), and severe and critical COVID-19 (P = .007 and P < .001, respectively) were associated with mortality. Conversely, patients receiving monoclonal antibodies, even for severe or critical COVID-19, had a lower mortality rate (P < .001). In the multivariable model, older age, active disease, critical COVID-19, and 2-3 comorbidities were correlated with a higher mortality, whereas monoclonal antibody administration, alone (P < .001) or combined with antivirals (P = .009), was protective. Although mortality is significantly lower than in the prevaccination era, breakthrough COVID-19 in HM is still associated with considerable mortality. Death rate was lower in patients who received monoclonal antibodies, alone or in combination with antivirals.

Genetic polymorphisms in IL-2, IL-10 and FOXP3 are associated with autoimmune neutropaenia in early childhood and autoantibody specificity in a Danish cohort.

Autoimmune neutropaenia (AIN) in early childhood is characterized by chronic neutropaenia and positivity for human neutrophil antibodies (HNA), resulting in the excessive destruction of neutrophils. The association between regulatory T cells (Tregs) and AIN has been described, and in this study, we investigated three Treg-associated genes, IL-2, IL-10 and FOXP3. The frequencies of three single nucleotide polymorphisms (SNPs) in IL-2 -330T>G (rs2069762), +114G>T (rs2069763) and IVS3-116 A>G (rs2069772), four SNPs in IL-10 -3575T>A (rs1800890), -1082G>A (rs1800896), -819 C>T (rs1800871) and -592 C>A (rs1800872) and three SNPs in FOXP3 -3499 A>G (rs3761547), -3279 C>A (rs3761548) and -924 A>G (rs2232365) were compared between 166 Danish AIN patients and 358 healthy controls. Disease association was observed for IL-2 IVS3-116 GG (p = 0.0081, OR = 0.35 [0.15-0.80]), IL-10 -3575 TT (p = 0.0078, OR = 1.71 [1.16-2.54]) and IL-10 -1082 AA (p = 0.014, OR = 1.76 [1.14-2.72]) in all patients and FOXP3 -924 (p = 0.0005, A OR = 0.41 [0.25-0.68] and G OR = 2.42 [1.46-4.01]) in male patients. None of the associations were linked to antibody specificity. Disease-associated haplotypes were observed in IL-2 and FOXP3. IL-2 -330T/+114 T/IVS3-116A was associated with anti-FcγRIIIb-positive patients (p = 0.012, OR = 2.07 [1.18-3.62]). FOXP3 -3499A/-3279C/-924A was associated with anti-HNA-1a-positive male patients (p = 0.016, OR = 0.41 [0.20-0.83]), and ACG was associated with female patients, both in the combined group (p = 0.006, OR = NA) and the anti-FcγRIIIb-positive group (p = 0.002, OR = NA). We conclude that our findings reveal a correlation between SNP in Treg-associated genes and AIN, indicating that AIN could be driven by dysfunction of immune homeostatic-evolving Tregs.

Beyond adenosine triphosphate: unveiling the pleiotropic effects of pyruvate kinase activation in sickle cell anemia.

Not available.

Dexamethasone treatment for COVID-19 is related to increased mortality in hematologic malignancy patients: results from the EPICOVIDEHA Registry.

Not available.

Survival in multiple myeloma and SARS-COV-2 infection through the COVID-19 pandemic: Results from the EPICOVIDEHA registry.

Patients affected by multiple myeloma (MM) have an increased risk of severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection and subsequent coronavirus (20)19 disease (COVID-19)-related death. The changing epidemiological and therapeutic scenarios suggest that there has been an improvement in severity and survival of COVID-19 during the different waves of the pandemic in the general population, but this has not been investigated yet in MM patients. Here we analyzed a large cohort of 1221 patients with MM and confirmed SARS-CoV-2 infection observed between February 2020, and August 2022, in the EPICOVIDEHA registry from 132 centers around the world. Median follow-up was 52 days for the entire cohort and 83 days for survivors. Three-hundred and three patients died (24%) and COVID-19 was the primary reason for death of around 89% of them. Overall survival (OS) was significantly higher in vaccinated patients with both stable and active MM versus unvaccinated, while only a trend favoring vaccinated patients was observed in subjects with responsive MM. Vaccinated patients with at least 2 doses showed a better OS than those with one or no vaccine dose. Overall, according to pandemic waves, mortality rate decreased over time from 34% to 10%. In multivariable analysis, age, renal failure, active disease, hospital, and intensive care unit admission, were independently associated with a higher number of deaths, while a neutrophil count above 0.5 × 109 /L was found to be protective. This data suggests that MM patients remain at risk of SARS-CoV-2 infection even in the vaccination era, but their clinical outcome, in terms of OS, has progressively improved throughout the different viral phases of the pandemic.

Clinically meaningful improvements in patient-reported outcomes in mitapivat-treated patients with pyruvate kinase deficiency.

Clinically meaningful benefits in the signs, symptoms, and impacts of #PKDeficiency as assessed by disease-specific patient-reported outcome measures were observed in mitapivat-treated adult patients in two phase 3 clinical trials.

Thrombosis Tendency After Splenectomy in a Danish Family With Hemoglobin Volga, and a Literature Review.

Hemoglobin (Hb) Volga is a rare, unstable ß-chain hemoglobin variant (ß27 Ala→Asp), causing chronic hemolytic anemia. This study presents two members of a Danish family, splenectomized due to Hb Volga at and with multiple thrombotic events. The proband was diagnosed with Hb Volga 9 years old and splenectomy was performed as a part of treatment. Throughout his life, he experienced multiple superficial thrombophlebitis, two episodes of distal deep venous thrombosis (DVT) on lower extremities (age 32 and 33) and a transient ischemic attack (TIA) presented as amaurosis fugax (age 51). Thrombophilia investigation was normal. The proband's son was diagnosed with Hb Volga and underwent splenectomy at the age of 6. Despite anticoagulation therapy, he suffered from multiple venous thromboembolic events in his youth and died of chronic pulmonary embolism (PE)/pulmonary hypertension combined with infection. Given the observed propensity for multiple thromboses in these two patients, a literature review was conducted investigating reported occurrence of thrombotic events in individuals with Hb Volga.Currently 25 cases of Hb Volga are reported worldwide. The clinical symptoms primarily described are related to hemolytic anemia. Splenectomy is reported in 15 patients. Thromboses have previously been reported in only three patients who were also splenectomized. These cases involved DVT and PE, myocardial infarction, and an unspecified thrombotic event. The proband represents the first reported Hb Volga case with both venous and arterial thrombotic disorders. The exact mechanism underlying thrombotic tendency in patients with Hb Volga remains unknown, but it is probably associated with splenectomy.

A Novel ß-Globin Variant, Hb Odder [HBB: C.316C > G; CD105 (Leu > Val)].

We report the discovery of a novel ß-globin gene variant, Hb Odder, characterized by a single nucleotide substitution; HBB:c.316C > G; CD105 (Leu > Val). This variant emerged incidentally during routine HbA1c measurements for diabetes monitoring. The patient exhibited no clinical or biochemical evidence of anemia or hemolysis. Our data on this variant suggest that Hb Odder is benign, regrettably limitations in our data make formal evaluations of stability and oxygen affinity impossible; additionally this emphasizes the importance of considering hemoglobin variants in the differential diagnosis of abnormal Hb A1c levels and suggest that laboratories should use alternative methods for the correct measurement of Hb A1c when hemoglobin variants interfere with diabetes monitoring. Notably, three other mutations have been described at codon 105 of the ß globin chains and correspond to three Hb variants with different characteristics: Hb South Milwaukee, Hb Bellevue IV and Hb St. George.

The evolving landscape of COVID-19 and post-COVID condition in patients with chronic lymphocytic leukemia: A study by ERIC, the European research initiative on CLL.

In this retrospective international multicenter study, we describe the clinical characteristics and outcomes of patients with chronic lymphocytic leukemia (CLL) and related disorders (small lymphocytic lymphoma and high-count monoclonal B lymphocytosis) infected by SARS-CoV-2, including the development of post-COVID condition. Data from 1540 patients with CLL infected by SARS-CoV-2 from January 2020 to May 2022 were included in the analysis and assigned to four phases based on cases disposition and SARS-CoV-2 variants emergence. Post-COVID condition was defined according to the WHO criteria. Patients infected during the most recent phases of the pandemic, though carrying a higher comorbidity burden, were less often hospitalized, rarely needed intensive care unit admission, or died compared to patients infected during the initial phases. The 4-month overall survival (OS) improved through the phases, from 68% to 83%, p = .0015. Age, comorbidity, CLL-directed treatment, but not vaccination status, emerged as risk factors for mortality. Among survivors, 6.65% patients had a reinfection, usually milder than the initial one, and 16.5% developed post-COVID condition. The latter was characterized by fatigue, dyspnea, lasting cough, and impaired concentration. Infection severity was the only risk factor for developing post-COVID. The median time to resolution of the post-COVID condition was 4.7 months. OS in patients with CLL improved during the different phases of the pandemic, likely due to the improvement of prophylactic and therapeutic measures against SARS-CoV-2 as well as the emergence of milder variants. However, mortality remained relevant and a significant number of patients developed post-COVID conditions, warranting further investigations.

Genetic variations in low-to-medium-affinity Fcγ receptors and autoimmune neutropenia in early childhood in a Danish cohort.

Autoimmune neutropenia (AIN) in early childhood is caused by autoantibodies directed against antigens on the neutrophil membrane and is a frequent cause of neutropenia in children. Association of AIN with Fcγ receptor (FCGR) 3B variants is well described. In this study, we investigate genetic variations in the FCGR locus and copy number variation of FCGR3B. A total of 130 antibody-positive AIN patients, 64 with specific anti-HNA-1a antibodies and 66 with broad-reacting anti-FcγRIIIb antibodies, were genotyped with a multiplex ligation probe assay and compared with healthy controls. Positive findings were confirmed with real-time q-PCR. We determined copy numbers of the FCGR2 and FCGR3 genes and the following SNPs: FCGR2A Q62W (rs201218628), FCGR2A H166R (rs1801274), FCGR2B I232T (rs1050501), FCGR3A V176F (rs396991), haplotypes for FCGR2B/C promoters (rs3219018/rs780467580), FCGR2C STOP/ORF and HNA-1 genotypes in FCGR3B (rs447536, rs448740, rs52820103, rs428888 and rs2290834). Generally, associations were antibody specific, with all associations being representative of the anti-HNA-1a-positive group, while the only association found in the anti-FcγRIIIb group was with the HNA-1 genotype. An increased risk of AIN was observed for patients with one copy of FCGR3B; the HNA genotypes HNA-1a, HNA-1aa or HNA-1aac; the FCGR2A 166H and FCGR2B 232I variations; and no copies of FCGR2B 2B.4. A decreased risk was observed for HNA genotype HNA-1bb; FCGR2A 166R; FCGR2B 232T; and one copy of FCGR2B promoter 2B.4. We conclude that in our Danish cohort, there was a strong association between variation in the FCGR locus and AIN. The findings of different genetic associations between autoantibody groups could indicate the presence of two different disease entities and disease heterogeneity.

A Novel ß-Globin Variant, Hb Raklev [ß 75(E19) HBB:c.227T > A (Leu→Gln)].

We present a new hemoglobin variant, Hb Raklev, characterized by the substitution of leucine with glutamine at position 75 in the ß-globin chain. This variant was discovered inadvertently during an HbA1c evaluation using high performance liquid chromatography in a symptomless 54-year-old Caucasian woman, with the same variant also identified in her 16-year-old daughter. Purification of the hemoglobin revealed possibly diminished 2,3-bisphosphoglycerate (2,3-BPG) sensitivity, which may result in heightened oxygen affinity. Notably, two variants have been previously documented at this location: the unstable Hb Atlanta and the high-affinity Hb Pasadena.

Oxygen gradient ektacytometry does not predict pain in children with sickle cell anaemia.

The loss of red blood cell (RBC) deformability in sickle cell anaemia (SCA) is considered the primary factor responsible for episodes of acute pain and downstream progressive organ dysfunction. Oxygen gradient ektacytometry (Oxygenscan) is a recently commercialised functional assay that aims to describe the deformability of RBCs in SCA at differing oxygen tensions. So far, the Oxygenscan has been evaluated only by a small number of research groups and the validity and clinical value of Oxygenscan-derived biomarkers have not yet been fully established. In this study we examined RBC deformability measured with the Oxygenscan in 91 children with SCA at King's College Hospital in London. We found a significant correlation between Oxygenscan-derived biomarkers and well-recognised modifiers of disease severity in SCA: haemoglobin F and co-inherited α-thalassaemia. We failed, however, to find any independent predictive value of the Oxygenscan in the clinical outcome measure of pain, as well as other important parameters such as hydroxycarbamide treatment. Although the Oxygenscan remains an intriguing tool for basic research, our results question whether it provides any additional information in predicting the clinical course in children with SCA, beyond measuring known markers of disease severity.

ABO, secretor, and Lewis carbohydrate histo-blood groups are associated with autoimmune neutropenia of early childhood in Danish patients.

BACKGROUND: Autoimmune neutropenia of early childhood (AIN) is caused by autoantibodies directed against antigens on the neutrophil membrane. The ABO, secretor, and Lewis histo-blood group systems control the expression of carbohydrate antigens and have previously been linked to autoimmune diseases. We aimed to investigate the association between genotypes and the risk of AIN in Danish patients. STUDY DESIGN AND METHODS: One hundred fifty-four antibody-positive AIN patients were included. Controls (n = 400) were healthy unrelated Danish blood donors. Molecular determination of ABO, secretor (FUT2), and Lewis (FUT3) genotypes were determined using real-time polymerase chain reaction (qPCR) or Sanger sequencing to infer the prevalence of Lewis antigens (Lea and Leb ) and secretor (SeSe or Sese) or nonsecretor (sese) phenotypes. RESULTS: Blood type O was more common in controls (46.8%) than in AIN patients (36.4%) (OR = 0.65; p = 0.028). Secretors of H Leb antigens were less frequent among AIN patients (25.2%) than controls (35.0%) (OR = 0.62; p = 0.037). DISCUSSION: ABO blood group antigens and the secretion of these antigens are associated with a diagnosis of AIN. The mechanism underlying the association between autoimmunity and interaction among ABO, secretor, and Lewis genotypes has not yet been elucidated, but several studies indicate a connection to the gut microbiota.

The significance of spleen size in children with sickle cell anemia.

It is well established that splenic dysfunction occurs in early childhood in sickle cell anemia (SCA), although the determinants and consequences of splenic injury are not fully understood. In this study, we examined spleen size and splenic function in 100 children with SCA aged 0-16 years at King's College Hospital in London. Spleen size was assessed by abdominal ultrasound (US) and splenic function by pitted red blood cells (PIT counts). In our cohort, 5.6% of children aged 6-10 years and 19.4% of children aged 11-16 years had no visible spleen on US (autosplenectomy). Splenomegaly was common in all age groups, with 28% of children overall having larger spleens than the average for their age. Only one child had a PIT count suggesting preserved splenic function. We found no correlation between hemoglobin F levels and spleen size, nor was there any difference in spleen size between children treated with or without hydroxyurea. Although there was a trend toward increased spleen length in children with co-inherited α-thalassemia, this did not reach statistical significance. Finally, we found a strong association between erythrocyte deformability measured with oxygen gradient ektacytometry, spleen size, and PIT counts. In conclusion, our results do not agree with the general perception that most children with SCA undergo autosplenectomy within the first decade of life and indicate that loss of erythrocyte deformability contributes to loss of splenic filtration capacity in SCA, as well as phenotypical variations in spleen size.

Hb Kalundborg [ß79(EF3)Asp→Glu; HBB: c.240C>a], a Possible Low-affinity Hemoglobin Variant Detected during Hb A1c Measurement.

A previously unknown hemoglobin (Hb) variant was detected during measurement of glycosylated Hb (Hb A1c) after the introduction of a new high performance liquid chromatography (HPLC) apparatus. Subsequent DNA sequencing revealed a heterozygous single nucleotide substitution at codon 79 (C>A) on the ß-globin gene changing an amino acid [ß79(EF3)Asp→Glu; HBB: c.240C>A]. The new Hb variant was named Hb Kalundborg after the place of origin of the proband. Heterozygosity for this mutation appears to have no clinical significance in itself except for a possibly slightly lower oxygen affinity. However, it interferes with Hb A1c measurement by HPLC, causing a falsely high Hb A1c concentration when using the G11 apparatus with clinical implications possibly to follow.

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.