What 869 trials say about diabetes drugs
A living BMJ review maps the benefits and harms of 63 drugs, showing why heart, kidney and weight priorities matter more than a single league table.
The 60-second version
A living BMJ review of 869 randomized trials shows that type 2 diabetes medicines have different strengths and harms, so treatment choice should follow a person's risk profile and priorities.
Key points
- SGLT-2 inhibitors and GLP-1 receptor agonists have established cardiovascular and kidney benefits, while finerenone benefits selected patients with chronic kidney disease.
- Tirzepatide produced the largest average weight reduction in the network, but weight is only one outcome and gastrointestinal harms matter.
- Network meta-analysis mixes direct and indirect comparisons, and absolute benefits depend strongly on baseline risk.
- Drug-specific harms include genital infection, ketoacidosis, gastrointestinal events, hyperkalaemia, fracture, heart-failure hospitalization and hypoglycaemia.
Verdict. Use the evidence to structure a clinician conversation, not to self-prescribe or chase a universal winner.
Bottom lineThe review is a map, not a single ranking
A living BMJ review combined 869 randomized trials involving 493,168 adults with type 2 diabetes. It found no one drug that wins every outcome: cardiovascular risk, kidney disease, weight, hypoglycaemia and adverse effects point toward different choices.
MethodHow the evidence network works
The review included randomized trials lasting at least 24 weeks. A network meta-analysis combines direct head-to-head trials with indirect comparisons through a shared comparator. That allows a broad map, but it also means certainty differs from one comparison to another.
The authors used GRADE to rate confidence and a random-effects model to allow for differences across studies. The search for this version ran through 31 July 2024; the project plans updates at least twice a year.
BenefitsHeart, kidney and weight outcomes do not align perfectly
Moderate- to high-certainty evidence confirmed cardiovascular and kidney benefits for SGLT-2 inhibitors and GLP-1 receptor agonists. Finerenone showed benefit for patients who already have chronic kidney disease. The absolute gain varies substantially with a person's baseline cardiovascular and kidney risk.
| Cardiovascular and kidney risk | SGLT-2 inhibitors and GLP-1 receptor agonists have established benefits; absolute gains are larger when baseline risk is higher. |
|---|---|
| Chronic kidney disease | Finerenone adds evidence for selected patients with established CKD, alongside its potassium risk. |
| Weight | Tirzepatide had the largest average reduction in the network; orforglipron followed, but its evidence was less certain. |
| Severe hypoglycaemia | Sulfonylureas, insulin and DPP-4 inhibitors probably increased risk. |
Those weight estimates are averages across a trial network, not forecasts for one person. They also do not settle other priorities such as glucose control, cardiovascular disease, kidney function, tolerability, cost or access.
HarmsEach class carries a different trade-off
| SGLT-2 inhibitors | More genital infections (OR 3.29) and diabetic ketoacidosis (OR 2.08); amputations probably increased modestly (OR 1.27). |
|---|---|
| Tirzepatide and GLP-1 drugs | Probably more severe gastrointestinal events; the largest estimate was for tirzepatide (OR 4.21). |
| Finerenone | More severe hyperkalaemia (OR 5.92), making potassium and kidney monitoring relevant. |
| Thiazolidinediones | More major osteoporotic fractures and probably more hospitalization for heart failure. |
LimitsWhat the review cannot settle
- Not every drug pair was compared directly; some estimates come from indirect links in the network.
- Trials differed in populations, follow-up and outcome definitions, even though statistical models account for heterogeneity.
- Evidence for neuropathy and visual impairment was low or very low certainty.
- Whether GLP-1 drugs reduce dementia remained uncertain: OR 0.92, 95% CI 0.83 to 1.02, with low certainty.
- The current search cutoff was July 2024, so a living review still requires later updates.
The best-supported choice depends on the outcome a patient most needs to improve and the harm they most need to avoid.
Next stepTurn the evidence into the right questions
For the next clinical review, bring a short list: cardiovascular disease or heart failure, kidney function, desired weight change, previous adverse effects, hypoglycaemia risk, other medicines, cost and access. The review makes those trade-offs easier to discuss; it does not replace individualized care.
Primary sourcesTelegram post 1438·BMJ paper·PubMed·Crossref record·PROSPERO CRD42022325948