Among 66,807 Danish diabetic patients over 20 years, GLP-1 combinations showed the best cardiovascular outcomes while metformin plus sulfonylurea showed the worst.
66,807 patients, 20 yearsentire Danish diabetic population shows GLP-1 combinations have best cardiovascular outcomes
What the researchers found
This massive real-world study compared outcomes across multiple diabetes drug combinations:
Worst performer: metformin plus sulfonylurea (SU) had the highest risk of cardiovascular events and death. Metformin plus basal insulin had the highest severe hypoglycemia risk.
Best cardiovascular protection: regimens including a GLP-1 receptor agonist had the lowest MACE risk.
Best overall: metformin + SGLT2 inhibitor + GLP-1 had the lowest risk for all three endpoints (cardiovascular events, severe hypoglycemia, and all-cause mortality).
Key clinical insight: adding GLP-1 to metformin + basal insulin reduced all three endpoints compared to metformin + insulin alone, especially severe hypoglycemia. This suggests GLP-1 agonists should be considered before or alongside insulin.
The results do not support sulfonylurea as the second-line treatment choice, a finding that aligns with evolving guidelines moving away from SU.
Why it matters
Real-world data from an entire national population is powerful because it captures outcomes that clinical trials may miss: medication adherence, complex patients, and long-term effects. This study provides the strongest real-world evidence that GLP-1 agonists should be prioritized over sulfonylureas as second-line diabetes drugs, and that the triple combination with SGLT2 inhibitors is optimal.
The numbers in context
66,807 patients; 20 years; MET+SU worst; MET+SGLT2i+GLP-1 best; GLP-1 addition to MET+insulin reduced all endpoints
How the study worked
Population-based cohort study using 20 years of data from the Danish National Patient Registry. All 66,807 type 2 diabetes patients treated with metformin plus various second- and third-line therapies were analyzed. Cox regression models assessed risk of MACE, severe hypoglycemia, and all-cause mortality across drug combinations.
Who was studied
66,807 type 2 diabetes patients from the Danish National Patient Registry
What this study cannot tell us
Observational study subject to confounding by indication. Sicker patients may receive insulin (making insulin look worse) while healthier patients may start GLP-1 drugs (making them look better). No randomization. Drug-specific effects within GLP-1 and SGLT2 classes were not separated. Some combinations had small patient numbers, reducing power for those comparisons.
How to read the evidence
Strong evidence from a large population-based cohort study. Observational design means confounding is possible but the scale is compelling.
When this study was published
Published in 2020. Prescribing patterns continue shifting toward GLP-1 and SGLT2 inhibitor use.
The bigger picture
Real-world evidence from an entire national population is powerful because it captures medication adherence, complex patients, and long-term outcomes that clinical trials may miss. This data supports the shift away from sulfonylureas toward GLP-1 and SGLT2 inhibitor combinations.
Questions still open
- Is the sulfonylurea risk real or due to confounding (sicker patients getting older drugs)?
- Should all insulin-requiring diabetics add GLP-1 therapy?
- Will this data influence national prescribing guidelines?
Common questions
Which diabetes drug combination is safest for the heart?
Should I ask my doctor to change my diabetes medication?
Read the original research
Risk of Major Adverse Cardiovascular Events, Severe Hypoglycemia, and All-Cause Mortality for Widely Used Antihyperglycemic Dual and Triple Therapies for Type 2 Diabetes Management: A Cohort Study of All Danish Users.
Diabetes care, 43(6), 1209-1218
Citation
Jensen, Morten Hasselstrøm; Kjolby, Mads; Hejlesen, Ole; Jakobsen, Poul Erik; Vestergaard, Peter. (2020). Risk of Major Adverse Cardiovascular Events, Severe Hypoglycemia, and All-Cause Mortality for Widely Used Antihyperglycemic Dual and Triple Therapies for Type 2 Diabetes Management: A Cohort Study of All Danish Users.. Diabetes care, 43(6), 1209-1218. https://doi.org/10.2337/dc19-2535