Hypertensive effect of bronchial asthma

Abstract

Background: Both bronchial asthma and hypertension are spastic disorders of smooth muscle, salt sensitive and sometimes associated with higher renin-angiotensin system activity, suggesting similarities between their aetiologies. This study was intended to assess the blood pressure status in asthmatic patients. Patients and Methods: The study involved two groups: a control group of 56 healthy subjects matched for gender and age with the study group of 100 patients with a medical history of asthma but no other respiratory disease. Asthma history was recorded to assess asthma activity at the time of examination together with medications. The non-invasive ausculatory method was used for measuring the systolic (SBP) and diastolic (DBP) blood pressures. Mean arterial blood pressure (MABP) was determined by the formula: MABP = DBP + [(SBP – DBP)/3]. Results: DBP was significantly higher in asthmatics (mean±SD = 80±10 mmHg) compared with non-asthmatics (mean±SD = 75±10 mmHg) (P = 0.002). DBP of off-treatment asthmatics was significantly higher compared with that of non-asthmatics (P = 0.015). Diastolic blood pressure of asymptomatic patients was not significantly higher compared with that of symptomatic patients (P = 0.774). Systolic and mean arterial blood pressures were not significantly different in asthmatics and control groups (P = 0.267 and 0.116 respectively). Conclusions: In contrast to systolic and mean arterial blood pressures, diastolic blood pressure was significantly elevated in asthmatics (even in off-treatment patients) compared with non-asthmatics indicating mechanisms that predominantly increases peripheral vascular resistance