Meta-analysis topic ideas in cardiology
Cardiology is one of the most trial-dense fields in medicine, which cuts both ways. The big questions (statins, anticoagulation, blood-pressure targets) have been pooled many times over, so a new review on them rarely adds anything. But the volume of trials also means that narrower questions often have enough studies to pool and no review yet.
The practical approach is to leave the headline drug classes alone and look at the edges: a population the large trials under-enrolled, an established drug in a new setting, or a procedure comparison where each trial is small.
Find a cardiology topic that has not been done
SynthGap searches the published literature, checks each candidate against existing systematic reviews, and proposes topics with the primary studies behind them. The free plan includes 3 discovery runs a month.
Start freeWhere gaps tend to hide in cardiology
Under-represented populations
Older adults, women, people with chronic kidney disease and frail patients are often too few in landmark trials for a clear answer. Pooling smaller trials that enrolled them, or reporting subgroup effects across trials, is a common source of new topics.
Established drugs in new settings
Anti-inflammatory and metabolic drugs first developed for other conditions are being tested around cardiac surgery, pericarditis, atrial fibrillation and heart failure. Early trials are small and a pooled estimate may not exist yet.
Perioperative and peri-procedural care
Post-operative atrial fibrillation, myocardial injury after surgery and contrast-related complications are studied in many small randomized trials that are rarely brought together.
Devices and procedures
Ablation strategies, closure devices and imaging-guided interventions are compared in trials that are individually underpowered for clinical outcomes.
Rehabilitation and digital care
Cardiac rehabilitation formats, telemonitoring and remote care vary widely, and reviews often go out of date quickly.
Outcomes and effect measures that pool well in cardiology
- Time-to-event outcomes such as mortality or first hospitalisation: pool the reported hazard ratios (generic inverse variance) instead of converting them to risk ratios.
- Composite endpoints such as MACE are defined differently from trial to trial. Pool the individual components (death, myocardial infarction, stroke) alongside the composite so readers can see what drives the result.
- Atrial fibrillation and other event rates over a fixed window: risk ratios, with the follow-up period stated.
- Left ventricular ejection fraction and similar imaging measures: mean difference, but note the imaging method, since echocardiography and MRI do not give interchangeable numbers.
- Blood pressure and LDL cholesterol are surrogate endpoints. They pool easily, but a reviewer will ask whether the clinical outcomes agree.
Common traps in cardiology reviews
- The same trial published several times (main results, sub-studies, long-term follow-up). Count each trial once, or you will double-count patients.
- Open-label trials with soft endpoints such as hospitalisation, where knowing the treatment can change behaviour.
- Mixing short and long follow-up in one pooled estimate without saying so.
- Treating subgroup differences found by comparing trials as if they were randomized comparisons: they are observational.
Check before you commit
Before committing months to a topic, check that nobody has beaten you to it. Search PubMed with its systematic review filter, the Cochrane Library, the PROSPERO register (for reviews that are registered but not yet published) and Epistemonikos. Look at how recent the latest review is and whether new trials have appeared since its search date. Step-by-step guide.
Starting points to try in SynthGap
These are areas to explore, not claims that they are open. Some may already be well covered, and finding that out quickly is the point.
- Colchicine for post-operative atrial fibrillation after cardiac surgery
- SGLT2 inhibitors in patients with advanced chronic kidney disease and heart failure
- Remote monitoring after hospital discharge for heart failure
Questions
How do I check whether a cardiology meta-analysis already exists?
Search PubMed with the systematic review filter, the Cochrane Library, PROSPERO for registered reviews that are not yet published, and Epistemonikos. Then look at how recent the latest review is and whether new trials have appeared since.
Should I pool hazard ratios or risk ratios?
Pool hazard ratios when trials report them for time-to-event outcomes. Use risk ratios for events counted over a fixed period, and do not mix the two in one estimate.
How many trials do I need for a meta-analysis?
Two is technically enough, but with fewer than about five trials the estimate of heterogeneity is unreliable. Report that as a limitation, or consider a narrative synthesis.
Other specialties
This page is general methodological guidance, not medical advice, and it does not list specific unreviewed topics. SynthGap's suggestions are AI-generated from the published literature, so verify them before registering a protocol.