How Low Should Blood Pressure Targets Go?

Should current guidelines lower the blood pressure treatment threshold for increased prevention of CVD?

Hypertension is one of the most common primary diagnoses in the United States and one of the leading causes of death worldwide. Hypertension is a significant risk factor for strokes, myocardial infarction, chronic kidney diseases, and vascular diseases. Unfortunately, surveys show that many adults with high blood pressure aren’t correctly diagnosed, and therefore, the correct medications for blood pressure-lowering aren’t prescribed. This furthermore represents a failure of the health systems; it’s known that BP-lowering medications are also helpful in significantly reducing chances of strokes, MI’s, CKD, and other severe cardiovascular issues that patients with high blood pressure are at significant risk for developing. Current guideline recommendations reflect the uncertainty around the balance of benefit vs. harm in blood pressure targets. From an epidemiologic perspective, it is established that risk for cardiovascular disease increases at blood pressure levels of greater than 115/75. Still, guidelines do not suggest treatment with medication for a blood pressure level of 115/75.

Furthermore, targets of 130/80 are reserved for patients with a CVD risk of >/= 15%, while a less stringent target of <140/90 is advised for lower-risk patients. Many studies and articles highlight how low is too low when lowering blood pressure. Many well-known informative health websites have articles on blood pressure lowering and hypotension. There are also guidelines on blood pressure-lowering that guide practitioners on how to dose medications based on blood pressure readings.

The purpose of this study is to evaluate the threshold or lowest blood pressure that still supports reduced CVD events. The analyzed study was a prospective epidemiologic cohort analysis; it included 593,196 adults without CVD separated into subgroups based on glycemic status: normoglycemic, prediabetic, and patients with diabetes. The subgroups were further divided into five other categories according to their SBP or DBP readings. Incidence of coronary artery disease or CVD events among the categories was studied. Study population mostly young adults, mean age of 44 normoglycemic, 48 prediabetic, and 52 diabetic.

The study showed a linear relationship between the risk of developing coronary artery disease and the level of the SBP and DBP. The risk of coronary artery disease was evident regarding the subject’s glycemic status. Furthermore, the study showed that the relative risk of developing cardiovascular and cerebrovascular complications was increased at an SBP of >/= 120 mmHg and DBP of >/= 75mmHg whether normoglycemic, prediabetic, or diabetic subgroup – an interesting finding due to the previous studies that are showing a J curve association between DBP and adverse cardiovascular events. These results are consistent with numerous previous studies; these reports call for stricter BP control in all patients to prevent CVD risk.

The study strengths included establishing an epidemiologic association between high blood pressure with a diverse study group compared to other studies where the participants were mainly from Europe and North America. In contrast, this study had participants from Japan and China. However, the weakness of this study was the fact that nonstandardized BP readings were collected and are less reliable. In conclusion, the study suggests the guidelines should be changed to recommend lower blood pressure goals. While the current recommendations suggest a target blood pressure of <130/80, the change to <120/80 would require more studies and analysis to justify lowering the target in the guidelines. 

Practice Pearls:

• Hypertension is the most common primary diagnosis in the USA and the leading cause of death worldwide.
• Risks of further CVD and CKD complications are higher in patients with blood pressures greater than SBP of 120 or DBP of 80.
• Further studies need to be done to reevaluate if guidelines should be changed to lower blood pressure recommendations. 

Aishah Matar, John W. McEvoy Diabetes Care Sep 2021, 44 (9) 1910 1912; DOI: 10.2337/dci21-0017 Matthew R Alexander, M. D. (2021, July 22). Hypertension. Practice Essentials, Background, Pathophysiology.

Erica Hicks, PharmD Candidate 2022, South College School of Pharmacy