DiRECT analysis supports antihypertensive withdrawal before very-low-calorie diet
medwireNews: Blood pressure (BP) falls markedly when people with type 2 diabetes undertake a very-low-calorie diet, and immediate withdrawal of antihypertensive medications has few ill effects, say the DiRECT investigators.
“Withdrawing antihypertensive medications was initially a concern for some GPs [general practitioners] in practices participating in DiRECT, uncertain whether weight loss would be achieved, or could provide good alternative treatment for hypertension,” they write in Diabetologia.
But systolic BP fell by a significant average 3.6 mmHg within the first week of the intervention, and by approximately 10 mmHg at week 20. The fall in diastolic BP achieved significance by week 3, at which point it had fallen by an average of 1.9 mmHg.
“Importantly, there was no worrying early rebound rises in BP,” say Michael Lean (University of Glasgow, UK) and co-researchers.
These BP reductions were significantly associated with weight loss, with each kg of weight lost linked to systolic and diastolic reductions of 0.53 and 0.34 mmHg, respectively.
“It was not possible to identify reliably at baseline the patients who would fail to lose weight or those whose BP responded less well to weight loss,” warn the investigators.
BP should therefore be closely monitored throughout the intervention period, they say, which “entails a small commitment from either healthcare staff or potentially patients themselves using home monitoring.”
And they observe that “[i]t is important that BP continues to be monitored, at least annually along with [glycated hemoglobin], as even without weight regain, BP often rises with age.”
This analysis included 143 DiRECT participants who were assigned to the total diet replacement group, of whom 57% had hypertension, with 96% taking antihypertensive medications – two or more in the case of 54%.
In line with the trial protocol, most (83%) people discontinued all antihypertensive medications when they started the 12–20-week total diet replacement period (825–853 kcal/day). Thirteen participants continued all or some of their medications, for reasons including cardiovascular comorbidities, high blood pressure, GP decision, or participant reluctance.
The researchers found that BP reduction was “immediate and quite substantial” for previously untreated participants, but slower in treated participants. BP reductions in those previously taking antihypertensive medications did not attain significance until around week 9, with the slowest changes seen in people initially taking two or more medications.
Around a third (36%) of the participants reported at least one episode of dizziness, potentially indicative of postural hypotension, during the diet-replacement phase, but this was mild in the majority (82%) of cases.
Two-thirds of people who had stopped all their antihypertensive medications had to reintroduce at least one. For 29%, this was required during the total diet replacement phase, and most of these people had been taking two or more antihypertensives at baseline. However, over a third (35%) of people who had to reintroduce their medications were able to stop them again within the first 12 months of the trial.
“The present analysis shows a bonus for those individuals who achieved remission, from the high likelihood of being able to withdraw antihypertensive and diuretic medications completely,” say the researchers.
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