INTERPRETATION Drug-class effects on interindividual variation in blood pressure can account for differences in effects of antihypertensive drugs on risk of stroke independently of effects on mean SBP .
INTRODUCTION Unexplained differences between classes of antihypertensive drugs in their effectiveness in preventing stroke might be due to class effects on intraindividual variability in blood pressure .
We did a systematic review to assess any such effects in r and omised controlled trials .
The Felodipine Event Reduction (FEVER) Study: a randomized long-term placebo-controlled trial in Chinese hypertensive patients
Objective To compare the incidence of stroke and other cardiovascular events in hypertensive patients receiving a low-dose diuretic and low-dose calcium antagonist combination with those receiving low-dose diuretic monotherapy  , and assess the effects of a small blood pressure difference at achieved levels lower than those achieved in previous placebo-controlled trials . Methods The Felodipine Event Reduction ( FEVER ) trial was an investigator- design ed , prospect i ve , multicentre , double-blind , r and omized , placebo-controlled , parallel group trial . It enrolled 9800 Chinese patients , of either sex , aged 50–79 years , with one or two additional cardiovascular risk factors or disease , whose blood pressure , 6 weeks after switching from previous antihypertensive therapy to low-dose ( 12.5 mg a day ) hydrochlorothiazide , was in the range 140–180 mmHg ( systolic ) or 90–100 mmHg ( diastolic ) . These patients were r and omly assigned either to low-dose felodipine extended release or placebo , and followed at 3-month intervals for an average of 40 months . Results The intention-to-treat analysis included 9711 r and omly selected patients with only 30 ( 0.3 % ) lost to follow-up . A total of 31 842 patient-years of follow-up were accumulated , with 85.9 % of patients remaining on blinded r and omized treatment . Add-on therapy was given to 33.9 % of the hydrochlorothiazide – felodipine patients and to 42.3 % of the hydrochlorothiazide – placebo patients . In the felodipine  group , systolic blood pressure (SBP)/diastolic blood pressure ( DBP ) decreased ( from r and omization to study end ) from 154.2/91.0 to 137.3/82.5 mmHg , and in the placebo group from 154.4/91.3 to 142.5/85.0 mmHg , with an average difference throughout the trial of 4.2/2.1 mmHg . In the felodipine group , the primary endpoint ( fatal and non-fatal stroke ) was reduced by 27 % ( P = 0.001 ) . Among secondary endpoints , all cardiovascular events were reduced by 27 % ( P < 0.001 ) , all cardiac events by 35 % ( P = 0.012 ) , death by any cause by 31 % ( P = 0.006 ) , coronary events by 32 % ( P = 0.024 ) , heart failure by 30 % ( P = 0.239 ) , cardiovascular death by 33 % ( P = 0.019 ) , cancer by 36 % ( P = 0.017 ) in the felodipine group . No significant differences were found in new-onset diabetes . Both treatments were very well tolerated . Conclusions In moderately complicated hypertensive patients from China even a difference in SBP/DBP as small as 4/2 mmHg , such as that induced by adding low-dose felodipine to low-dose hydrochlorothiazide , is associated with very substantial reductions in the incidence of most types of cardiovascular events . As the SBP achieved in the felodipine group was below the recommended goal of less than 140 mmHg , and SBP in the placebo group was slightly above that level , FEVER provides the required evidence in support of the guidelines recommended goal , even for a hypertensive population not entirely consisting of patients with diabetes or previous cardiovascular events
INTERPRETATION Drug-class effects on interindividual variation in blood pressure can account for differences in effects of antihypertensive drugs on risk of stroke independently of effects on mean SBP .
INTRODUCTION Unexplained differences between classes of antihypertensive drugs in their effectiveness in preventing stroke might be due to class effects on intraindividual variability in blood pressure .
We did a systematic review to assess any such effects in r and omised controlled trials .