Are Current Hypertension Goals Successful in Reducing Cardiovascular Risk in Patients with Diabetes?

This review examines the differing arguments recent studies have made regarding blood pressure / hypertension goals and cardiovascular risk in diabetes patients. 

Hypertension remains one of the leading reasons for high mortality, contributing to 20.3% of female deaths and 18.2% of male deaths. A possible reason could be that many adult patients with high blood pressure remain undiagnosed and are not taking blood pressure-lowering medications, which can significantly reduce cardiovascular disease. In addition, patients who are diagnosed with hypertension are not reaching their goal blood pressure levels. In patients with hypertension and diabetes, the 2017 American College of Cardiology/American Heart Association guidelines recommend a blood pressure goal of less than 130/80 mmHg. The European guidelines recommend a blood pressure goal of less than 130/80 mmHg and systolic blood pressure between 120 to 129 mmHg in patients less than 65 years old. Cardiovascular disease risk calculators are recommended when determining blood pressure targets for patients with diabetes. For patients with a 10-year cardiovascular disease risk of ≥15%, a target of <130/80 mmHg is recommended, while a target of <140/90 mmHg is advised for patients with a lower risk. The SPRINT trial, a randomized controlled trial, found that intensive treatment for blood pressure-lowering was significantly better than the standard treatment, regardless of age, sex, cardiovascular disease risk, chronic kidney disease, and blood pressure at the time of diagnosis. Previous prospective studies have also found that increased risk for cardiovascular disease begins when blood pressure is higher than 115/75 mmHg; however, there have not been enough clinical trials to support this number as a target blood pressure goal with medications. Therefore, it is essential to understand how much pharmacological treatment can reduce cardiovascular disease risk, in addition to blood pressure. 

Prospective cohort analysis in Japan examined the risk of coronary artery disease and cardiovascular disease risk among patients with normal glucose levels, prediabetes, and diabetes. Each group was divided based on systolic and diastolic readings. Most studies on blood pressure readings are in Caucasians, while this one was unique in Japan. Data based on diverse populations globally have the potential to differentiate cardiovascular disease risk and make further recommendations. This study required more strict blood pressure targets to prevent cardiovascular disease risk. This analysis showed a linear relationship between diastolic blood pressure readings and cardiovascular risk, and the risk of cardiovascular disease was apparent regardless of glycemia status. Cardiovascular complications and risks began to develop once systolic blood pressure reached greater than 120 mmHg and diastolic blood pressure greater than 75 mmHg in all three patient categories. However, previous studies have revealed that a higher risk for cardiovascular disease is not directly related to a lower diastolic blood pressure reading in patients with diabetes.

On the contrary, it could be possible that adults with lower diastolic blood pressure are usually older with comorbidities and higher cardiovascular disease risk. For example, the ACCORD trial did not find a significant difference in mortality, cardiovascular risk, stroke, and myocardial infarction between a systolic blood pressure target of less than 120 mmHg and less than 140 mmHg in patients with T2D. Further trials have also failed to show an added benefit of blood pressure targets less than 130/80 mmHg in patients with a low risk for cardiovascular disease. 

Current studies support the overall recommendation of a blood pressure target of less than 130/80 mmHg for patients with diabetes and a higher risk for cardiovascular disease. While a further reduction in blood pressure goals is not necessary at this current time, according to studies, patient education on diet and exercise should be stressed. In addition, future studies should exemplify a long-term cardiovascular benefit with a systolic blood pressure goal of less than 120 mmHg along with changes in lifestyle habits. 

Practice Pearls: 

• While the current practice guidelines recommend a target blood pressure goal of less than 130/80 mmHg, researchers in several trials aimed to discover why. 
• A prospective cohort study in Japan found a linear relationship between diastolic blood pressure and cardiovascular risk. In contrast, other studies have not found a significant difference in mortality between different blood pressure goals. 
• A further reduction in blood pressure target is not necessary at this time; however, it is essential to educate patients on non-pharmacological recommendations to reduce cardiovascular risk. 

References for “Are Current Hypertension Goals Successful in Reducing Cardiovascular Risk in Patients with Diabetes?”:

Kaul, Sanjay. “Evidence for the Universal Blood Pressure Goal of <130/80 mm Hg Is Strong: Controversies in Hypertension – Con Side of the Argument.” Hypertension

Lewington, Sarah et al. “Age-specific relevance of usual blood pressure to vascular mortality: a meta-analysis of individual data for one million adults in 61 prospective studies.” Lancet 

Matar, Aishah, and John W McEvoy. “Blood Pressure Limbo-How Low Can You Go?.” Diabetes care

Dalia Elabed, PharmD Candidate 2022, University of South Florida Taneja College of Pharmacy