Are blood pressure recommendations for type 2 diabetes too high?

People with type two diabetes should aim for a 120 mm Hg blood pressure to keep their risk of a major cardiovascular event low, say Jiao Tong University scholars. A massive clinical trial conducted in China has found that the current blood pressure recommendations for people with type 2 diabetes may need to be revised down.

In the study published last month in the New England Journal of Medicine, a consortium of doctors from across People’s Republic of China worked with Shanghai experts to investigate whether current blood pressure guidelines for type 2 diabetes are missing the mark. One of the most common complications of type two diabetes is its effect on the cardiovascular system; people with type 2 diabetes are at an increased risk of stroke and heart attack.

How low should we go?

For many years, standard treatment for type two diabetics has been to encourage people to keep their blood pressure below the cut-off point for hypertension. Hypertension is a condition where an individual’s blood pressure is high enough that it escalates their risk of a cardiovascular event. The lower limit for hypertension is a systolic blood pressure of 140 mm Hg. Systolic blood pressure is a measure of the force that blood applies to your artery walls when your heart beats.

In theory keeping your blood pressure below the cut-off should be sufficient to reduce your chances of a stroke or a heart attack, but is this also true for type two diabetics? Shanghai Jiao Tong University scholars say, ‘no’. After a huge randomized controlled study including over 12,000 participants, researchers have concluded that type two diabetics, at least in Asia, should try for blood pressure of 120 mm Hg or less to minimize their risk.

Current practice in most regions is that people with type 2 diabetes should be aiming for a systolic blood pressure of 140 mm Hg. The idea is that at more than 140 mm Hg, the stress on your arteries can lead to hardening of the blood vessel walls or mechanical damage that can contribute to atherosclerosis and other conditions.

The Weight of Risk

Doctors have long known that when people take action to reduce their blood pressure, their chance of having a stroke or a heart attack goes down. Whether this is because lower blood pressure is gentler on your blood vessels, or because the same underlying problem that makes blood pressure high also makes cardiovascular events more likely, the outcome is the same.

Lower blood pressure means lower risk of heart attack, stroke, heart failure and other cardiovascular events.

The challenge comes, however, when you have more than one risk factor for cardiovascular troubles. Imagine each risk factor for heart attack or stroke is a pebble you carry around with you. The more stones in your pocket, the harder you have to work your cardiovascular system to get through each day.

You might have a pebble illustrating your stress levels, another bigger one representing carrying a few extra inches on the belly. A boulder could be your smoking habit and a small rock could represent the fact that you had pre-eclampsia during your pregnancy. Yet another small stone might be that you have a genetic predisposition to high blood pressure. A small pebble represents high systolic blood pressure (that’s more than 120 mm Hg) and a large rock corresponds to hypertension (blood pressure above 140 mm Hg). The metabolic changes that come with type 2 diabetes add another boulder to the pile.

Tossing rock will lower your chances of having a heart attack or a stroke. Some stones are more tricky to lose than others. If you can’t get rid of the diabetes boulder, dropping some of your other stones that add up to a similar size could be a way to lower your risk. So should type two diabetics be dropping their high blood pressure stone along with their hypertension rock?

Is it time to rethink the tipping point for diabetics?

Are blood pressure recommendations for Type 2 diabetics too high?

The Shanghai researchers hypothesized that dropping the target blood pressure to 120 mm Hg should reduce the number of cardiovascular events such as stroke or heart attack in type 2 diabetics. They ran a straight forward experiment comparing the outcomes of type 2 diabetics who continued with normal hypertension therapy with type 2 diabetics who aimed for a blood pressure of 120 mm Hg with a more intensive treatment regime. Would lowering the target blood pressure reduce the number of heart attacks and strokes after five years?

In a controlled, randomized clinical trial, the doctors recruited over 12,000 participants across 145 hospitals and clinics. The researchers assembled a cohort of type 2 diabetics aged over 50 years old. They each had a systolic blood pressure between 130 mm Hg and 180 mm Hg if they had been taking blood pressure medicine and 140 mm Hg if they weren’t using meds. Finally, the participants all had a high risk of cardiovascular problems. This included people with chronic kidney disease and a history of clinical or subclinical cardiovascular disease for at least three months or three years respectively before the trial.

The doctors randomly assigned each participant to one of two groups. These were people who would follow the standard treatment for high blood pressure. They would use antihypertensive drugs to aim for a blood pressure below 140 mm Hg. The other group would be using antihypertensives to get their blood pressure under 120 mm Hg. The groups were evenly matched in terms of age, sex, education, medical history and baseline blood work.

Every three months, the clinics would use an electronic data system to relay check up stats to the researchers. They would collect information on blood pressure, kidney function, cardiovascular health and any reports of a cardiovascular event. Cardiovascular events included non-fatal stroke, non-fatal heart attack, treatment or hospitalization for heart failure, or death from cardiovascular causes.

The team followed then followed the 12,821 participants over the next five years to see which treatment protocol would win out.

The patients knew which treatment group they were in, but the doctors who would collect and analyse their cardiovascular data throughout the trial did not know who was receiving which care.

Under pressure

At the end of the study, the results were clear. The average starting blood pressure was 140 mm Hg plus or minus 10 mm Hg for both groups. After just a year of intensive blood pressure control, the 120 mm Hg target group had an average systolic blood pressure of 118 mm Hg. The standard treatment group on average achieved 133 mm Hg. The two groups maintained these average blood pressures for the next four years.

The intervention worked, as far as blood pressure goes, but would it lead to a drop in cardiovascular problems? Well, after five years, the researchers report, participants who aimed for a blood pressure under 120 mm Hg were 21% less likely to have had a primary cardiovascular outcome than people who stuck to the standard treatment. In the intensive blood pressure control group 393 out of 6414 participants suffered a stroke, heart attack, were treated for heart failure or died due to cardiovascular causes. In the standard treatment group, 492 of 6407 participants experienced these outcomes. The difference between the two groups was both statistically significant and clinically significant.

The groups were equally likely to experience adverse events from the treatment, around 36%. This indicated that intensive blood pressure control was no more harmful than standard treatment. The differing approaches to blood pressure did not affect the rate of chronic kidney disease progression.

A Stroke of luck

All in all, the researchers concluded that that 21% drop in the risk of a poor cardiovascular outcome with intensive blood pressure control demonstrates that it’s worth considering revisiting the standard of care for type two diabetics.

They did make some observations about the limitations of their study. Firstly, people dropped out throughout the trial. While they started with 12,821, by the end of year five they only collected data for around 3000 participants. The study started just before the pandemic, and so for a least a year some patients were self-reporting data to the clinics over the phone. The researchers also looked only at systolic blood pressure. They did not test how diastolic blood pressure responded to the treatment or how it related to cardiovascular events. The trial was only partially blinded – both the participants and their treating doctors knew which treatment they were getting. Placebo effects or bias in reporting outcomes could factor in.

Finally, people of East Asian descent have a higher risk of type 2 diabetes, hypertension and cardiovascular disease than other populations. People with Chinese heritage are more likely to develop metabolic syndrome at a lower BMI than white European populations, for example. This means that the intensive blood pressure control approach for type two diabetics might need to be tested in other ethnic groups before adopting it as a standard of care.

Take the Pressure Off

These findings, the authors say, are very encouraging when it comes to preventing stroke. Within Chinese populations, hypertension is the biggest risk factor for non-fatal stroke and fatal stroke. Stroke is the most common cardiovascular-related condition for this demographic. Non-fatal strokes can cause long-term disabilities that significantly impact quality of life and people’s ability to care for themselves.

Let’s return to our pocket full of pebbles. The good news is that for people of Chinese descent, while they might be carrying larger rocks representing genetic high blood pressure, type 2 diabetes and BMI, dropping the hypertension and the high blood pressure stones is relatively easy with antihypertensives. Dropping the blood pressure target to below 120 mm Hg for type two diabetics has a significant effect on the number of lives extended and reducing the debilitating long-term complications that result from a stroke.

Bi Y, Li M, Liu Y, et al. Intensive Blood-Pressure Control in Patients with Type 2 Diabetes. New England Journal of Medicine. 2025;392(12):1155-1167. doi:10.1056/NEJMoa2412006