Doctors may be overprescribing anti-hypertensives in people with type 2 diabetes by relying only on threshold triggers rather than absolute risk to initiate treatment, researchers say.

Australian and international investigators in the ADVANCE trial found in a post hoc analysis that not all patients gain equivalent benefit from BP-lowering treatment and that an algorithm based on routine clinical data could identify patients with T2DM who would benefit most from the drugs.

ADVANCE was a randomised controlled trial evaluating the effect of intensive glucose control and routine BP-lowering therapy (perindopril-indapamide) or placebo on vascular events and death.

In the new study, researchers used their algorithm retrospectively on data from the 11,000 ADVANCE patients, identifying 17% of people who would have very little absolute risk reduction (ARR) benefit from BP-lowering drugs, thus potentially eliminating unnecessary treatment-related cost, side-effects, or adherence issues.

“There’s an automatic tend­ency in doctors’ minds that once people hit 140/90mmHg we’ve got to get out our prescription pad,” agreed Professor Mark Harris, a leading primary care researcher, who was not involved in the study.

Professor Chalmers, senior director at the George Institute, said the algorithm used 14 variables — including diabetes duration, HBA1c and eGFR — to identify people who would benefit most from treatment.

It was hoped the calculator could be integrated into existing GP software, he said.

Professor Harris, executive director of the Centre for Primary Health Care and Equity at the University of New South Wales,  said while updated diabetes guidelines published in 2012 supported treatment decisions based on absolute risk rather than BP level, the reality is that many doctors still aggressively treated all T2DM patients with a BP of 140/90mmHg.

Low-risk patients would still need BP to be managed with lifestyle interventions