George Institute for Global Health develops new online tool for high blood pressure management

New Delhi: A first-of-its-kind Blood Pressure Treatment Efficacy Calculator built on data from nearly 500 randomised clinical trials in over 100,000 people allows doctors to see by how much different medications are likely to lower blood pressure.

The research, published in The Lancet, could transform how the condition is managed, allowing doctors to choose a treatment for each patient based on the degree to which they need to lower their blood pressure.

“This is really important because every 1mmHg reduction in systolic blood pressure lowers your risk of heart attack or stroke by two percent,” said Nelson Wang, cardiologist and Research Fellow at The George Institute for Global Health.

“But with dozens of drugs, multiple doses per drug, and most patients needing two or more drugs, there are literally thousands of possible options, and no easy way to work out how effective they are,” he said.

Speaking about the research, Dr. Mohammad Abdul Salam, Program Head, Cardiovascular Research, The George Institute for Global Health, Hyderabad, India, said, “We cannot overlook the importance of controlling high blood pressure effectively and efficiently. Achieving optimal control requires a clear understanding of the efficacy of antihypertensive drugs at different doses and in various combinations. Without clarity on what we want to achieve and how to achieve it, we will not meet our targets. Guidelines define the target blood pressure, while our online tool helps identify which antihypertensive drugs are best suited to reach that target.”

The new tool helps overcome this challenge by calculating the average treatment effect seen across hundreds of trials. It also categorises treatments as low, moderate, and high intensity, based on how much they lower blood pressure (BP) – an approach already routinely used in cholesterol lowering treatment.

A single antihypertensive medication – still the most common way treatment is started – typically lowers systolic BP by just 8-9 mmHg, while most patients need reductions of 15-30 mmHg to reach ideal targets.

Dr Nelson Wang explained that while the traditional way of doing this is by measuring blood pressure directly for each patient and adjusting treatment accordingly, in fact BP readings are far too variable, or ‘noisy’, for it to be reliable.

“Blood pressure changes from moment to moment, day to day and by season – these random fluctuations can easily be as big or larger than the changes brought about by treatment,” he said.

“Also, measurement practices are often not perfect, bringing in an additional source of uncertainty – this means it’s very hard to reliably assess how well a medicine is working just by taking repeated measurements.”

Anthony Rodgers, Senior Professorial Fellow at The George Institute for Global Health, said that while hypertension, or high blood pressure, is the most common reason people visit their doctor, there has been no single, up-to-date resource to show how effective different blood pressure medications are—especially when used in combination or at varying doses.

“Using the calculator challenges the traditional ‘start low, go slow, measure and judge’ approach to treatment, which comes with the high probability of being misled by BP readings, inertia setting in or the burden on patients being too much,” he said.

“With this new method you specify how much you need to lower blood pressure, choose an ideal treatment plan to achieve that based on the evidence, and get the patient started on that ideally sooner rather than later.”

The next step is to test this new approach in a clinical trial, where patients will be prescribed treatments based on how much they need to lower their blood pressure, guided by the calculator.

High blood pressure is one of the world’s biggest health challenges, affecting as many as 1.3 billion people and leading to around ten million deaths each year.2

Often called a silent killer as it does not cause any symptoms on its own, it can remain hidden until it leads to a heart attack, stroke or kidney disease. Fewer than one in five people with hypertension have it under control.3

“Given the enormous scale of this challenge, even modest improvements will have a large public health impact – increasing the percentage of people whose hypertension is under control globally to just 50% could save many millions of lives,” Professor Rodgers added.

The Blood Pressure Treatment Efficacy Calculator can be accessed at www.bpmodel.org.