Association between relative systemic hypertension and otologic disorders in patients with sickle cell‐hemoglobin C disorder
Authors: Nathalie Lemonne, Marc Romana, Yann Lamarre, Marie‐Dominique Hardy‐Dessources, François Lionnet, Xavier Waltz, Vanessa Tarer, Danielle Mougenel, Benoît Tressières, Marie‐Laure Lalanne‐Mistrih, Maryse Etienne‐Julan, Philippe Connes
Journal: American Journal of Hematology (2014)

To the Editor: The definition of systemic hypertension (HTN) is not clearly established in sickle cell patients. Although sickle cell-hemoglobin C (SC) patients have slightly lower systolic blood pressure (SBP) and diastolic blood pressure (DBP) values than the general population 1, they have higher blood pressure values than patients with homozygous sickle cell anemia (SCA) 1. Recently, in SCA, it was reported that increased blood viscosity could be a risk factor for relative systemic HTN (SBP/DBP > 120/70 mmHg) 2 and that relative systemic hypertension could be a risk factor for several chronic complications in SCA, such as glomerulopathy and pulmonary hypertension 3. However, these relationships have not been investigated in SC patients. We used the data of 89 SC adult patients (M/F: 40/49; mean age: 38 ± 13 years), regularly followed by the Sickle Cell Center of Pointe-à-Pitre (Guadeloupe), to address these issues. The cohort characteristics, including inclusion and exclusion criteria, have been previously reported 4. While leg ulcers, pulmonary hypertension, priapism, and cerebral vasculopathy were very rare in our cohort, retinopathy (60%), glomerulopathy (40%), osteonecrosis (31%), and otologic disorders (20%) were frequent 4. Blood pressures (SBP/DBP) were measured for each patient, as recommended 2. Systemic arterial HTN was defined using the three cutoff values previously proposed for sickle cell patients: (1) HTN1 > 120/70 mmHg 5; (2) HTN2 > 130/80 mmHg 6; or (3) HTN3 > 140/90 mmHg 5. Hematological and hemorheological parameters (blood viscosity, red blood cell deformability, and aggregation) were performed as previously described 4. Results are reported in the Table 1. When using the HTN1 cutoff (i.e., relative systemic HTN), we found a trend for greater hematocrit (P < 0.1) and higher blood viscosity (+11%; P < 0.01) in patients with relative systemic HTN than in those without. Blood viscosity was still higher in SC patients with SBP/DBP greater than the HTN2 cutoff values compared to patients with SBP/DBP below this cutoff (+11%; P < 0.05). We also noted a trend toward patients with HTN2 being older than patients with SBP/DBP below the HTN2 cutoff values (P < 0.1). Finally, using the HTN3 cutoff, the significant difference in blood viscosity between the two subgroups (i.e., patients with SBP/DBP below vs. above HTN3 cutoff values) did not persist (P = 0.18). However, we noted a significant correlation between blood viscosity and the severity of HTN (r = 0.35; P < 0.01). SC patients with HTN3 were older (P < 0.05) and had greater red blood cell aggregates strength than patients with SBP/DBP below HTN3 cutoff (P < 0.05). Whatever the SBP/DBP cutoff used, HTN was neither associated with glomerulopathy, nor with osteonecrosis or retinopathy. In contrast, we observed an association between otologic disorders and HTN when using the HTN1 cutoff, with 69% of patients with otologic disorders having HTN (P < 0.05). Our findings support the need to closely monitor blood pressure levels in SC patients as the presence of relative systemic hypertension (i.e., SBP/DBP > 120/70 mmHg), which was associated with blood viscosity level, could indicate a risk to develop otologic disorders. SC clinical management should include close monitoring of blood pressure level, particularly when it rises above 120/70 mmHg. Nathalie Lemonne1 Marc Romana2,3,4 Yann Lamarre2,3,4 Marie-Dominique Hardy-Dessources2,3,4 François Lionnet5 Xavier Waltz2,3,4 Vanessa Tarer1 Danielle Mougenel1 Benoît Tressières6 Marie-Laure Lalanne-Mistrih2,3,4,6 Maryse Etienne-Julan1,2,3,4 Philippe Connes2,3,4,7,8,9* 1Unité Transversale de la Drépanocytose, CHU de Pointe-à-Pitre, Pointe-à-Pitre, Guadeloupe; 2Inserm UMR 1134, Hôpital Ricou, CHU de Pointe-à-Pitre, Pointe-à-Pitre, Guadeloupe; 3Université des Antilles et de la Guyane, Pointe-à-Pitre, Guadeloupe; 4Laboratory of Excellence GR-Ex, (The red cell: from genesis to death), PRES Sorbonne Paris Cité, Paris, France; 5Centre de Référence de la Drépanocytose, Hôpital Tenon, AP-HP, Paris, France; 6Centre d'Investigation Clinique Antilles Guyane, Inserm/DGOS CIC 1424, CHU de Pointe-à-Pitre, Pointe-à-Pitre, Guadeloupe; 7Laboratoire ACTES EA3596, Pointe à Pitre, Guadeloupe; 8Institut Universitaire de France, Paris, France