Blood pressure and glycaemic effects of dapagliflozin versus placebo in patients with type 2 diabetes on combination antihypertensive therapy: a randomised, double-blind, placebo-controlled, phase 3 study.

Background: Hypertension is a common comorbidity in patients with type 2 diabetes mellitus and a major risk factor for microvascular and macrovascular disease. Although the blood pressure-lowering effects of sodium-glucose cotransporter 2 (SGLT2) inhibitors are already established, guidance is needed on how to use these drugs in patients already receiving antihypertensive therapy. We aimed to compare blood pressure and glycaemic effects of the SGLT2 inhibitor dapagliflozin with placebo in patients with inadequately controlled type 2 diabetes mellitus and hypertension.

Methods: In this double-blind, placebo-controlled, phase 3 study we enrolled patients from 311 centres in 16 countries across five continents. Patients had uncontrolled type 2 diabetes (HbA1c 7·0%-10·5%; 53-91 mmol/mol) and hypertension (systolic 140-165 mm Hg and diastolic 85-105 mm Hg at both enrolment and randomisation, and a mean 24 h blood pressure of ≥130/80 mm Hg by ambulatory monitoring within 1 week of randomisation) and were receiving oral antihyperglycaemic drugs, insulin, or both, plus a renin-angiotensin system blocker and an additional antihypertensive drug. Using an interactive voice-response system, we randomly assigned (1:1) patients to dapagliflozin 10 mg once a day or to placebo, with randomisation stratified by additional antihypertensive drug use and insulin use at baseline, in a block size of two. The co-primary endpoints were changes in seated systolic blood pressure and HbA1c measured in the full analysis set, which included all patients who received at least one dose of study drug and had both a baseline and at least one post-baseline measurement of efficacy. This trial is registered with ClinicalTrials.gov, number NCT01195662.

Findings: Between Oct 29, 2010, and Oct 4, 2012, we randomly assigned 225 patients to dapagliflozin and 224 to placebo. Seated systolic blood pressure was significantly reduced in the group assigned to dapagliflozin (adjusted mean change from baseline -11·90 mm Hg [95% CI -13·97 to -9·82]) compared with those assigned to placebo (-7·62 mm Hg [-9·72 to -5·51]; placebo-adjusted difference for dapagliflozin -4·28 mm Hg [-6·54 to -2·02]; p=0·0002). Reductions in HbA1c concentrations were also significantly greater in patients assigned to dapagliflozin (adjusted mean change from baseline -0·63% [95% CI -0·76 to -0·50]) than in those assigned to placebo (-0·02% [-0·15 to 0·12]; placebo-adjusted difference -0·61% [-0·76 to -0·46,]; p<0·0001). In a post-hoc analysis, we found difference in blood pressure versus placebo was greater in patients receiving a β blocker (-5·76 mm Hg [95% CI -10·28 to -1·23]) or a calcium-channel blocker (-5·13 mm Hg, [-9·47 to -0·79]) as their additional antihypertensive drug than in those receiving a thiazide diuretic (-2·38 mm Hg [-6·16 to 1·40]). Adverse events were similar in the dapagliflozin and placebo groups (98 [44%] patients vs 93 [42%], respectively, had at least one adverse event), with few adverse events related to renal function (1% vs <1%) or volume depletion (<1% vs 0%).

Interpretation: Dapagliflozin 10 mg significantly improved blood pressure and HbA1c and was tolerated similarly to placebo. Its blood pressure-lowering properties were particularly favourable in patients already receiving a β blocker or calcium-channel blocker. Dapagliflozin could benefit patients with type 2 diabetes who need a diuretic-like effect to optimise control of blood pressure, adding meaningful efficacy to antihypertensive drug regimens.

Funding: Bristol-Myers Squibb, AstraZeneca.