[Arterial blood pressure in homozygote patients with drepanocytosis]

Relative hypotension has been reported in sickle cell patients. The aim of this study was to compare blood pressure in patients with SS disease and subjects with normal hemoglobin genotype AA and to assess whether the same clinical, biological and socio-demographic variables are associated to the mean arterial pressure in patients with sickle cell disease and normal subjects.

Blood pressure was measured with a standardized automated oscillometric method in 88 SS patients et 88 AA control subjects seen in the University Hospital of Pointe-à-Pitre (Guadeloupe). A multiple linear regression analysis for mean arterial pressure was done including type of hemoglobin (forced variable), age, sex, body mass index, pulse rate, hemoglobin concentration and interaction terms between type of hemoglobin and other variables. A regression was also fitted separately for each population. A downward stepwise strategy was used to simplify the models.

The two groups were similar for age, height and gender ratio and pulse rate. Mean arterial pressure was significantly lower in sickle cell patients (81.6 mmHg in SS patients vs 89.9 mmHg in AA subjects, p < 10(-4)). The final model included type of hemoglobin, age, sex, body mass index, pulse rate and an interaction between type of hemoglobin and age (global F = 22.04, adjusted R2 = 42%). The separate models indicated that sex was associated with mean arterial pressure only in patients with sickle cell disease and that age and hemoglobin concentration was associated with mean arterial pressure only in normal subjects.

Blood pressure determinants are not similar in the two populations. The effect of age, especially, is not the same in patients with sickle cell disease and in normal subjects. These results confirm that specific patho-physiological models should be defined in sickle cell disease.