Scientists build online tool to calculate effectiveness of blood pressure medications

New Delhi, Aug 9 (PTI) Researchers have developed an online tool that can calculate the extent to which blood pressure medicines prescribed by a doctor will be effective, potentially allowing treatment to be tailored to suit a patient's needs.

The team, including researchers from The George Institute for Global Health in Australia and India, built the tool after reviewing and analysing data from nearly 500 previously published studies involving over a lakh participants.

Described in a paper in The Lancet journal, the 'Blood Pressure Treatment Efficacy Calculator' allows doctors to prescribe medicines based on the degree to which a patient's blood pressure needs to be lowered.

"This is really important because every 1 mmHg reduction in systolic blood pressure lowers your risk of heart attack or stroke by two per cent," author Nelson Wang, a cardiologist and research fellow at The George Institute for Global Health, Australia, said.

"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.

Drugs are the most common way hypertension (high blood pressure) is treated, with a single medication typically lowering systolic blood pressure -- the top number in a reading -- by only eight to nine mmHg, while most patients need to lower by 15-30 mmHg to reach ideal targets, the researchers said.

Along with calculating how effective a prescription will be, the online tool also categorises a treatment as 'low', 'moderate' or 'high' intensity, based on the extent to which one's blood pressure is estimated to fall.

Trials that the researchers analysed involved adult participants who were randomly assigned to receive beta-blockers (which block brain chemicals such as adrenaline) and calcium channel blockers (which stop calcium from entering the muscles of the heart and blood vessels), among other types of hypertension medications.

On average, a single drug at a standard dose was found to reduce systolic blood pressure by 8.7 mmHg, with a doubling of the dose lowering the value by an additional 1.5 mmHg.

A two-drug combination at standard dose was found to lower systolic blood pressure by about 15 mmHg, with each doubling of the dose of both the drugs bringing the value down by an additional 2.5 mmHg.

"A model was developed to calculate efficacy for any combination of antihypertensives and validated on external trials of dual and triple combination antihypertensives," the authors wrote.

As a next step, the calculator will be tested in clinical trials involving patients, the researchers said. PTI KRS KRS KSS KSS