Due to the new ACC/AHA task force hypertension guidelines (ACC/AHA), concerns have been raised that the lower cut-off values of blood pressure (BP) categories will lead to a relevant increase of hypertension prevalence. However, not only the cut-off values were changed, but also office blood pressure measurement (BPM) technique was redefined. Our aim was to study the differences in systolic BP classification based on BPM techniques recommended by the American and Canadian guidelines (CHEP).
In this cross-sectional, single-centre trial, 1000 adult subjects were recruited. After five minutes of rest, four sequential standard office BPM were performed at two-minute intervals in a quiet room and in sitting position. Based on the ACC/AHA, we calculated the mean of the first and second systolic BPM (sBPM). Based on the CHEP, we calculated the mean of the second and third sBPM. A systolic BP (sBP) < 120 mmHg was regarded as normal, 120–129 mmHg as elevated and >129 as hypertensive, as per ACC/AHA definition. BP differences were calculated using a related-samples Wilcoxon Signed Rank Test.
Complete measurements were available in 805 subjects. 195 patients were excluded due to incomplete measurements. Median sBP was 126 (114.5–138) mmHg in ACC/AHA technique and 123 (112.5–135) mmHg in CHEP technique (p-value < 0.005), with 199 (24.7%) subjects showing a higher BP value with CHEP technique and 580 (72.0%) subjects with the ACC/AHA technique. 26 subjects had the same sBP with both techniques (Figure 1). Applying both BPM techniques during one BPM session, lead to disagreement regarding sBP classification in 20% of cases. Comparing CHEP and AHA/ACC technique 344 (43%) vs. 297 (37%) subjects were classified as normal BP, 194 (24%) vs. 188 (23%) as elevated BP and 267 (33%) vs. 320 (40%) as hypertensive BP (Figure 2).
There are significant differences in sBP values and classification depending on the guideline regarding BPM technique applied. 20% of hypertensive patients based on ACC/AHA would be reclassified to a lower BP category by applying CHEP.
1University Hospital Basel, Medical Outpatient Department, Basel, Switzerland
2University Hospital Basel, Department of Internal Medicine, Basel, Switzerland
3University Hospital Basel, Department of Cardiology, Basel, Switzerland