Lower blood pressure with antihypertensive treatments can protect patients against heart attacks but does not reduce sudden cardiac deaths, according to new research conducted by researchers from the Université Claude Bernard, in France.
The researchers conducted a retrospective meta-analysis of 15 trials that included 39,908 patients, investigating the effects of blood pressure-lowering drugs on hypertensive predominant patients (>50%). High blood pressure was defined as having a baseline resting systolic blood pressure (SBP) of at least 140mmHg and/or resting diastolic blood pressure (DBP) of at least 90mmHg.
Patients were split into groups containing those who were administered antihypertensives and those who were administered placebo. The primary outcome researchers analyzed was sudden cardiac death, while the secondary outcomes included fatal myocardial infarction, non-fatal myocardial infarction, and withdrawals due to adverse effects.
Those in the antihypertensive group did not have less risk of sudden cardiac death than those receiving placebo, 12 per 1000 to 13 per 1000 for antihypertensive and placebo, respectively (risk ratio (RR) 0.96, 95% confidence interval (CI) 0.81 to 1.15). However, antihypertensives were shown to reduce both non-fatal myocardial infarction (RR 0.85, 95% CI 0.74 to 0.98) and fatal myocardial infarction (RR 0.75, 95% CI 0.62 to 0.90).
The lack of risk reduction in the antihypertensive group suggests that acute myocardial infarction is not the sole cause of sudden cardiac death. The authors tested the possibility of diuretics potentially inducing sudden cardiac deaths by causing hypokalaemia, though they found the pooled risk ratio of 1.08 did not point to differential effects for diuretics.
The authors also suggested that sudden cardiac death may for the time being be a misnomer, and until such time where a good estimate of its causes has been confirmed it might be better labeled ‘sudden death’.
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