Impact of metformin use on the cardiovascular effects of dipeptidyl peptidase-4 inhibitors: An analysis of Medicare claims data from 2007 to 2015

Could metformin modulate cardiovascular outcomes differently with DPP-4 inhibitors compared with SGLT2 inhibitors?

AIMS

Preliminary data have suggested that metformin might potentiate cardiovascular (CV) protection by dipeptidyl peptidase-4 inhibitors (DPP-4is), but reduce CV protection by sodium-glucose cotransporter type-2 inhibitors (SGLT2is), in patients with type 2 diabetes (T2DM) at high CV-related risk. For this reason, the present meta-analyses aimed to compare metformin moderation of the CV effects of the two pharmacological classes.

METHODS

Major adverse CV events (3-point MACEs) were counted in high-risk patients with T2DM treated with or without metformin as background therapy in five CV outcome trials with DPP-4is (SAVOR-TIMI 53, EXAMINE, TECOS, CARMELINA, CAROLINA) involving 24,821 patients (17,870 with and 6951 without metformin) and 2550 events (1696 with and 854 without metformin), and four trials with SGLT2is (EMPA-REG OUTCOME, CANVAS, DECLARE-TIMI 58, VERTIS CV) involving 24,563 patients (19,090 with and 5473 without metformin) and 1829 events (1300 with and 529 without metformin).

RESULTS

DPP-4is failed to reduce 3-point MACEs in both metformin users (OR: 0.96, 95% CI: 0.89-1.03) and non-users (OR: 1.05, 95% CI: 0.95-1.16), with no heterogeneity between trials and no significant between-subgroup differences (P = 0.4074), whereas SGLT2is significantly reduced 3-point MACEs in both patients with (OR: 0.91, 95% CI: 0.84-0.98) and without (OR: 0.81, 95% CI: 0.71-0.91) metformin, but again with no heterogeneity between trials and no significant between-subgroup differences (P = 0.2977). Overall, metformin non-users had a poorer risk profile than metformin users.

CONCLUSION

Our meta-analyses involving a larger number of trials than before have revealed that background metformin therapy has no significant influence on either the neutral impact of DPP-4is or the positive impact of SGLT2is on CV events (3-point MACEs) in T2DM patients at high CV risk.

Are the cardiovascular and kidney benefits of empagliflozin influenced by baseline glucose-lowering therapy?

AIMS

In the EMPA-REG OUTCOME® trial, the sodium-glucose cotransporter 2 inhibitor empagliflozin when given in addition to standard care improved cardiovascular (CV) and renal outcomes, and reduced mortality. Trial participants were on a variety of glucose-lowering therapies at baseline, some of which could potentially affect CV risk. This analysis investigated whether the use of background diabetes therapy affected the risk of CV death, hospitalizations for heart failure, and progression of chronic kidney disease, among patients treated with empagliflozin.

MATERIALS AND METHODS

Patients meeting inclusion and exclusion criteria were randomized to placebo, empagliflozin 10 mg or empagliflozin 25 mg; glucose-lowering therapy was to remain unchanged for 12 weeks and then adjusted to achieve glycaemic control according to local guidelines. Differences in risk of cardio-renal outcomes between empagliflozin and placebo by baseline use of metformin, sulphonylurea (SU) and insulin were assessed using a Cox proportional hazards model.

RESULTS

Of 7020 eligible patients, 74% were receiving metformin, 43% SU and 48% insulin at baseline (each alone or in combination); the most common regimens were metformin plus SU (20%) and metformin plus insulin (20%). Empagliflozin reduced the risk of CV death irrespective of the use of: metformin [with: hazard ratio (HR) 0.71 (95% confidence interval, CI, 0.54-0.94); without: 0.46 (0.32-0.68); P_interaction = 0.07]; SU [with: HR 0.64 (0.44-0.92); without: 0.61 (0.46-0.81); P_interaction = 0.85]; or insulin [with: HR 0.63 (0.46-0.85); without: 0.61 (0.44-0.85); P_interaction = 0.92]. Reductions in three-point major adverse CV events, hospitalizations for heart failure, and all-cause mortality were consistent across subgroups of baseline therapies. Empagliflozin reduced the risks of incident or worsening nephropathy versus placebo irrespective of the use of SU or insulin at baseline (P_interaction > 0.05), but there was a greater reduction in this risk for patients not using metformin [HR 0.47 (95% CI 0.37-0.59)] versus those using metformin [HR 0.68 (95% CI 0.58-0.79)] at baseline (P_interaction = 0.01).

CONCLUSIONS

The addition of empagliflozin to antihyperglycaemic regimens of patients with type 2 diabetes and CV disease consistently reduced their risks of adverse CV outcomes and mortality irrespective of baseline use of metformin, SU or insulin. For chronic kidney disease progression, there may be a larger benefit from empagliflozin in those patients who are not using metformin.

Heart failure in the patient with diabetes: Epidemiology, aetiology, prognosis, therapy and the effect of glucose-lowering medications

In people with type 2 diabetes the frequency of heart failure (HF) is increased and mortality from HF is higher than with non-diabetic HF. The increased frequency of HF is attributable to the cardiotoxic tetrad of ischaemic heart disease, left ventricular hypertrophy, diabetic cardiomyopathy and an extracellular volume expansion resistant to atrial natriuretic peptides. Activation of the renin-angiotensin-aldosterone system and sympathetic nervous systems results in cardiac remodelling, which worsens cardiac function. Reversal of remodelling can be achieved, and cardiac function improved in people with HF with reduced ejection fraction (HFrEF) by treatment with angiotensin-converting enzyme inhibitors and β-blockers. However, with HF with preserved ejection fraction (HFpEF), only therapy for the underlying risk factors helps. Blockers of mineralocorticoid receptors may be beneficial in both HFrEF and HFpEF. Glucose-lowering drugs can have a negative effect (insulin, sulphonylureas, dipeptidyl peptidase-4 inhibitors and thiazolidinediones), a neutral effect (α-glucosidase inhibitors and glucagon-like peptide-1 receptor agonists) or a positive effect (sodium-glucose co-transporter-2 inhibitors and metformin).