Effects of blood pressure lowering on cardiovascular events, in the context of regression to the mean: a systematic review of randomized trials

Journal article

Objective: To assess the clinical relevance of regression to the mean for clinical trials and clinical practise.

Methods: MEDLINE was searched until February 2018 for randomized trials of BP lowering with over 1000 patient-years follow-up per group. We estimated baseline mean BP, follow-up mean (usual) BP amongst patients grouped by 10 mmHg strata of baseline BP, and assessed effects of BP lowering on coronary heart disease (CHD) and stroke according to these BP levels.

Results: Eighty-six trials (349,488 participants), with mean follow-up 3.7 years, were included. Most mean BP change was due to regression to the mean rather than treatment. At high baseline BP levels, even after rigorous hypertension diagnosis, downwards regression to the mean caused much of the fall in BP. At low baseline BP levels, upwards regression to the mean increased BP levels, even in treatment groups. Overall, a BP reduction of 6/3 mmHg lowered CHD by 14% (95% CI 11%-17%) and stroke by 18% (15%-22%), and these treatment effects occurred at follow-up BP levels much closer to the mean than baseline BP levels. In particular, more evidence was available in the systolic BP (SBP) 130-139 mmHg range than any other range. Benefits were apparent in numerous high-risk patient groups with baseline mean SBP<140 mmHg.

Conclusion: Clinical practise should focus less on pre-treatment BP levels, which rarely predict future untreated BP levels or rule out capacity to benefit from BP lowering in high cardiovascular risk patients. Instead, focus should be on prompt, empirical treatment to maintain lower BP for those with high BP and/or high risk.

Authors: Salam, A; Atkins, E; Sundström, J; Hirakawa, Y; Ettehad, D

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Lippincott, Williams and Wilkins
• Journal: Journal of Hypertension More from this journal
• Volume: 37
• Issue: 1
• Pages: 16–23
• Publication date: 2018-12-18
• Acceptance date: 2018-09-25
• DOI: 10.1097/HJH.0000000000001994
• EISSN: 1473-5598
• ISSN: 0263-6352
• Keywords: blood pressure; systematic review; stroke; coronary Heart Disease; antihypertensive therapy; regression to the mean