Blood pressure-lowering treatment could harm some patients with diabetes

People with diabetes who have systolic blood pressure levels under 140 mm Hg and are treated with blood pressure-lowering drugs could have an increased risk of dying from cardiovascular causes, research suggests.
These findings were reported by at Umeâ University, Sweden. People with diabetes are more likely to have higher blood pressure and cardiovascular disease, so researchers Mattias Brunström and Bo Carlberg investigated how antihypertensive treatment affected diabetic patients with different blood pressure levels.
The blood pressure targets set by NICE for people with diabetes vary slightly depending on diabetes type. People with type 1 diabetes should aim to keep their blood pressure below 135/85 mm Hg; people with type 2 diabetes should aim for below140/80 mm Hg, but this target drops to below 130/80 mm HG if you have diabetic nephropathy (kidney disease) or two signs of metabolic syndrome.
The researchers collected data from 49 published and unpublished studies involving nearly 74,000 participants, most of whom had type 2 diabetes. They found that the effects of antihypertensive treatment depend on patients’ blood pressure levels before treatment – specifically, systolic blood pressure.
If a patient had systolic blood pressure higher than 140 mm Hg before beginning treatment, they experienced a decreased risk of death, stroke, heart attack and heart failure. However, these benefits did not apply to patients whose systolic blood pressure was below 140 mm Hg. These patients actually had a 15 per cent increased risk of cardiovascular death.
Brunström clarified that because the majority of patients had type 2 diabetes, no conclusions can be made regarding people with type 1 diabetes or patients with diabetes and normal blood pressure levels.
Brunström explained: “In practice, it is important to remember that undertreatment of high blood pressure is a bigger problem than overtreatment. At the same time, […] blood pressure-lowering treatment is crucial for the majority of people with diabetes whose blood pressure measures above 140.
“Many treatment guidelines, both Swedish and international, will be redrawn in the next few years. It has been discussed to recommend even lower blood pressure levels for people with diabetes – maybe as low as 130. We are hoping that our study, which shows potential risks of such aggressive blood pressure lowering treatment, will come to influence these guidelines.”
The authors added that blood pressure treatment aims should be handled less aggressively among people with diabetes, and doctors should use caution when prescribing treatment.
The study was published in the BMJ.