A Study Is Conducted to Assess the Role of Different

A study is conducted to assess the role of different treatment regimens on cardiovascular outcomes.  Two treatment arms are evaluated:  high-dose hydrochlorothiazide (100 mg/day) and low-dose hydrochlorothiazide (25 mg/day) .  After a defined follow-up period, the mean systolic blood pressure (BP) in the high-dose group is 139 mm Hg, with a mean diastolic BP of 88 mm Hg.  In the low-dose group, the mean values are 143 mm Hg and 92 mm Hg, respectively.  A 2-sample t-test gives p-values of 0.03 for the systolic BP and 0.04 for the diastolic BP differences between the high-dose and low-dose groups.  The relative risk of sudden cardiac death in the low-dose as compared to the high-dose group is 0.4 (95% confidence interval 0.25-0.55) . Another subset of patients from this sample was given a placebo, and the risk of sudden cardiac death was assessed.  When compared to the low-dose hydrochlorothiazide group, the placebo group's relative risk of sudden cardiac death was very close to 1.0.  The mean systolic and diastolic blood pressures in the placebo group were higher when compared to the low-dose hydrochlorothiazide group.  Which of the following is the best statement concerning the risk of sudden cardiac death in the overall sample of patients?

A) High-dose hydrochlorothiazide increases the risk of sudden cardiac death by a factor of ~2.5.
B) High-dose hydrochlorothiazide increases the risk of sudden cardiac death by roughly 50%.
C) Hydrochlorothiazide is a safe drug regardless of the dose.
D) Low-dose hydrochlorothiazide decreases the risk of sudden cardiac death by a factor of ~8.
E) The risk of sudden cardiac death in the sample is high.