7B.07: CIGARETTE SMOKING REDUCES BLOOD PRESSURE RESPONSE TO ANTIHYPERTENSIVE TREATMENT IN NEWLY DIAGNOSED HYPERTENSIVE PATIENTS

Objective: Smoking and hypertension are important risk factors in the development of cardiovascular disease (CVD). Control rates of hypertension are quite poor with only <50% of patients achieving target blood pressure (BP) after antihypertensive monotherapy. Smokers may have a blunted response to antihypertensive drugs but this has not been properly investigated. Therefore we studied the interaction between smoking status and BP response in never-treated hypertensive patients. Design and method: We studied 305 untreated hypertensive subjects (mean age 51 ± 1, mean ± SEM, F = 124) classified according to their smoking status; non- smoker (n = 134), smoker (n = 64) and ex- smoker (n = 104). Haemodynamic measurements including systolic and diastolic BP and heart rate (HR) were measured before and 1 month after monotherapy with commonly used antihypertensive agents;Data were analyzed using with JMP version 7.1 (SAS) for Windows. Results were expressed as mean ± SEM, with p < 0.05 considered significant. Results: There was a significant relationship between smoking status and fall in BP; smokers and ex- smokers showed lower reduction than non- smokers for systolic BP (4 ± 1.7 vs. 13.6 ± 1 vs. 17.6 ± 1) and diastolic BP (6.5 ± 1.0 vs. 8.7 ± 0.8 vs. 10 ± 0.7, p < 0.01) respectively. In a stepwise regression analysis, baseline systolic BP, smoking status and female gender were the only significant predictors of fall in systolic BP (R2 = 0.19, p < 0.0001) with smokers exhibiting 2 mm Hg less fall than smokers and ex-smokers. For reduction in diastolic BP, baseline diastolic BP and smoking status were the only significant predictors R2 = 0.19, p < 0.0001) with smokers showing 2 mmHg less reduction in diastolic BP compared with non- smokers. Conclusions: Smoking is not only an important cardiovascular risk factor in hypertensive patients but also reduces the response to anti-hypertensive treatment, independent of age, gender and body mass index. Therefore, smoking cessation can achieve not only reduced cardiovascular risk but may also improve BP control in hypertensive patients.