Blood pressure indices and disease severity in patients with sickle cell anaemia.

Background: Individuals with sickle cell anaemia (SCA) have lower systemic blood pressures compared to individuals with haemoglobin Hb AA phenotype.

Objective: Seventy-nine (79) individuals with SCA (subjects) in steady state and 50 age-matched individuals with Hb AA (controls) were prospectively studied. Height, blood pressure (BP), weight, creatinine clearance (by 24-hour urine collection), full blood count (FBC) and reticulocyte count were obtained from all subjects and controls. Body mass index (BMI), corrected reticulocyte count, mean arterial pressure (MAP) and pulse pressure (PP) were calculated using standard protocols.The frequency of vaso-occlusive crises in the last one year and number of blood transfusions in the last two years were obtained from subjects. Data was analyzed using descriptive and inferential statistics and p ≤0.05 was used to define the level of statistical significance.

Methodology: Seventy-nine (79) individuals with SCA (subjects) in steady state and 50 age-matched individuals with Hb AA (controls) were prospectively studied. Height, blood pressure (BP), weight, creatinine clearance (by 24-hour urine collection), full blood count (FBC) and reticulocyte count were obtained from all subjects and controls. Body mass index (BMI), corrected reticulocyte count, mean arterial pressure (MAP) and pulse pressure (PP) were calculated using standard protocols.The frequency of vaso-occlusive crises in the last one year and number of blood transfusions in the last two years were obtained from subjects. Data was analyzed using descriptive and inferential statistics and p ≤0.05 was used to define the level of statistical significance.

Results: The systolic (105.52±11.75mmHg and 113.20±7.94mmHg respectively; P = 0.01), diastolic (62.59±9.33mmHg and 75.40±5.70mmHg respectively; P=0.03) and mean arterial pressures (76.90±8.81mmHg and 88.00±5.51mmHg respectively; P =0.04) were significantly lower in subjects when compared with controls. ; pulse pressure (PP) was however significantly higher in subjects than controls (42.92±10.91mmHg and 37.80±7.43mmHg respectively (P = 0.03). In female subjects, the white cell count was negatively correlated with systolic BP (r = -0.39;P = 0.01) and PP (r = -0.33; P = 0.03).

Conclusion: Lower systolic and pulse pressures may predict worsening disease severity in individuals with sickle cell anaemia.