Discussion
This post hoc analysis evaluated attainment of glycemic and BP quality measures for diabetes. A significantly greater proportion of patients achieved the individual quality measures of A1C < 7% and A1C < 8% with dual add-on saxagliptin plus dapagliflozin to metformin compared with single add-on saxagliptin or dapagliflozin to metformin after 24 weeks. Similar results were seen when the analysis excluded patients with A1C < 7% and < 8% at baseline. All measures of good glycemic control had clinically relevant NNTs ≤ 10 after 24 weeks with saxagliptin plus dapagliflozin plus metformin compared with saxagliptin or dapagliflozin plus metformin, regardless of baseline status. Very few patients experienced lackof improvement in glycemic control, evidenced by small proportions of patients with A1C > 9%.
There was little difference in BP between dual add-on saxagliptin plus dapagliflozin or single add-on saxagliptin or dapagliflozin to metformin. The proportion of patients who attained the BP quality measure of BP < 140/90 mm Hg was similar across the 3 treatments, as might be expected because most patients already met this target at baseline. However, as might be expected based on the mild diuretic effect and weight loss associated with SGLT-2 inhibitors [16,17], trends in BP favored groups treated with dapagliflozin.
Attainment of multiple treatment targets is desirable in reducing complications of diabetes. A significantly greater proportion of patients achieved both A1C < 7% and BP < 140/90 mm Hg when both saxagliptin and dapagliflozin were added to metformin compared with single-agent addition of either saxagliptin or dapagliflozin plus metformin. Similarly, a significantly greater proportion of patients achieved both A1C < 8% and BP < 140/90 mm Hg with dual addition of saxagliptin and dapagliflozin plus metformin compared with saxagliptin plus metformin. There was also a numerically greater number of patients who achieved both of these goals with triple therapy compared with dapagliflozin plus metformin, but this finding did not reach statistical significance. Clinically relevant NNT values ≤ 10 were observed for both composite outcomes for saxagliptin plus dapagliflozin plus metformin compared with saxagliptin plus metformin or dapagliflozin plus metformin after 24 weeks.
Despite advances in the medical management of T2D, a report published in 2013 showed that between 2007 and 2010, only 53% of patients achieved an A1C < 7.0% and only 19% simultaneously achieved all 3 American Diabetes Association (ADA) goals recommended for most patients at that time: A1C < 7.0%, BP < 130/80 mm Hg, and low-density lipoprotein cholesterol LDL-C < 100 mg/dL [18]. These data highlight a need for new approaches to help patients attain glycemic, BP, and cholesterol goals. Our results demonstrated that a higher proportion of patients attained glycemic and BP quality measures with dual add-on saxagliptin plus dapagliflozin compared with single add-on saxagliptin or dapagliflozin to metformin. As a result of recent updates for cholesterol management from the American College of Cardiology and the American Heart Association [19], attainment of a cholesterol level was retired as a diabetes quality measure and replaced with a recommendation for statin therapy use [20,21]. Although the current analysis did not include assessment of LDL, DPP-4 inhibitors have demonstrated neutral effects on lipids [22,23], and SGLT-2 inhibitors have demonstrated generally modest increases in LDL-C (placebo-adjusted change from baseline: 4.5%–8.0% for canagliflozin 100 and 300 mg/d, 3.9% for dapagliflozin 10 mg, and 2.3%–4.2% for empagliflozin 10 and 25 mg/d) [12,24,25], as well as increases in high-density lipoprotein cholesterol and reductions in triglycerides [26].