Placebo administration in patients with isolated systolic hypertension significantly reduced mean systolic blood pressure by 9.4 mmHg at 4 weeks (p=0.003), unlike in systo-diastolic hypertension.
Observational (n=78)
Does placebo administration reduce blood pressure differently in patients with isolated systolic hypertension compared to systo-diastolic hypertension?
Patients with isolated systolic hypertension exhibit a significant placebo or white coat effect, suggesting that initiation of antihypertensive therapy could potentially be delayed for up to 3 months of careful follow-up.
p-value: p=0.003
It is well recognised from many clinical trials that there is a blood pressure lowering effect when placebo is administered to patients with essential hypertension ("placebo effect"). The reduction in blood pressure, however, may also be partly due to loss of the alerting response ("white coat effect") as a result of familiarisation with the clinical environment. To investigate the hypothesis that there may be a more marked placebo effect and white coat effect in isolated systolic hypertension (ISH) compared with systo-diastolic hypertension (SDH), we studied 78 patients with hypertension: 34 had ISH and 44 patients had SDH. The 34 patients with ISH were older (68.7 vs 54.9 years), had a higher SBP (192.2 vs 169.6 mmHfg) and lower DBP (85.5 vs 102.0 mmHg) when compared to patients with SDH. Amongst the patients with ISH, there were no significant changes in mean blood pressures pre-placebo (paired t-test, p = NS). In the placebo period, there was a significant reduction in systolic blood pressures at all three points, and a significant reduction in diastolic blood pressures after 2 and 3 months placebo (paired t-test, p < 0.05). There was a mean reduction in mean systolic blood pressure at visit 1 by 5.2%, visit 2 by 5.1% and visit 3 by 4.6%, when compared to mean pre-placebo systolic blood pressures (p < 0.05). The mean reduction in diastolic blood pressure was 5.8% at visit 2 and 3.5% at visit 3, when compared to mean pre-placebo diastolic blood pressure (p < 0.05). At the 4-week visit after receiving placebo, the mean systolic blood pressure decreased by 9.4 mmHg (p = 0.003) and mean diastolic blood pressure by 2.7 mmHg (p = NS) in the patients with ISH. In patients with SDH, there were no statistically significant changes in recorded BP readings following the introduction of placebo. We suggest blood pressures in some patients with ISH may settle with careful follow up and initiation of treatment in these patients could potentially be delayed for at least 3 months, as therapy may not prove necessary.
Gregory Y. H. Lip Dirk C. Felmeden (Sat,) conducted a observational in Isolated systolic hypertension and systo-diastolic hypertension (n=78). Placebo vs. Systo-diastolic hypertension group (or pre-placebo baseline) was evaluated on Change in systolic and diastolic blood pressure (p=0.003). Placebo administration in patients with isolated systolic hypertension significantly reduced mean systolic blood pressure by 9.4 mmHg at 4 weeks (p=0.003), unlike in systo-diastolic hypertension.
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