Meta-analysis topic ideas in nephrology
Nephrology has fewer large trials than cardiology, and for years people with kidney disease were excluded from the trials that guide other fields. The result is a literature with many observational studies, a modest number of randomized trials, and a steady stream of new drug classes that now report kidney outcomes.
A good nephrology review chooses its outcome carefully. Kidney function changes slowly, and the outcome that matters most to patients, kidney failure, is rare in a short trial, so much of the evidence rests on surrogate measures. Saying clearly what the review pools, and why, is part of the topic.
Find a nephrology 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. Start on the Free plan: no card needed, and every run shows every topic it finds.
Sign up freeWhere gaps tend to hide in nephrology
Drugs developed for other conditions
Glucose-lowering, cardiovascular and anti-inflammatory drugs now report kidney outcomes. The trials tend to enrol people with diabetes or heart disease, and what they show for people with established kidney disease of other causes is often a question for pooling subgroup data across trials.
Dialysis care
Haemodialysis schedules, dialysate composition, vascular access, anticoagulation and exercise during dialysis are studied in many small trials. Outcomes such as quality of life, access patency and intradialytic hypotension are measured inconsistently.
Kidney transplantation
Immunosuppression regimens, desensitisation and the management of infections after transplantation produce trials in the dozens, not the hundreds. Pooling by regimen and time since transplant is usually more informative than pooling everything.
Acute kidney injury
Prevention around surgery and contrast exposure, and the timing of dialysis, have conflicting trial evidence, partly because the definitions of the injury changed over time. Reviews that stratify by definition are useful.
Conservative care and symptoms
Itch, fatigue, sleep problems and depression in kidney disease, and decisions about not starting dialysis, are studied with small trials and qualitative work. Reviews of these patient-centred questions are common and often thin.
Outcomes and effect measures that pool well in nephrology
- Estimated glomerular filtration rate (eGFR) slope: mean difference in annual change, noting the equation used, since equations give different numbers. Short trials often report change over weeks, which can reflect haemodynamic effects rather than long-term decline.
- Kidney failure (dialysis or transplant), a doubling of serum creatinine or a sustained eGFR fall of 40 or 50 per cent: hazard ratios, with the composite definition written out and the components pooled separately where reported.
- Albuminuria or proteinuria: ratio of means or log-transformed measures, because the values are skewed. Say whether the urinary albumin-to-creatinine ratio or 24-hour excretion was used.
- Mortality and cardiovascular events in dialysis populations: hazard ratios or risk ratios, taking account of the high competing risk of death when the outcome is something else.
- Serum phosphate, potassium, haemoglobin and parathyroid hormone: mean differences. These are surrogate outcomes, and a reviewer will ask whether patient-important outcomes agree.
Common traps in nephrology reviews
- Treating a short-term drop in eGFR after starting a drug as kidney damage, when it can be a reversible haemodynamic effect.
- Ignoring the competing risk of death: in older dialysis patients, death often comes before kidney failure or an outcome such as a fracture.
- Pooling people with and without diabetes, or at very different stages of kidney disease, without checking that the effect is similar.
- Using observational dialysis registry data to compare treatments without addressing confounding by indication.
- Different definitions of acute kidney injury across eras (RIFLE, AKIN, KDIGO) in a single pooled estimate.
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 Cochrane Kidney and Transplant group has a large library), PROSPERO for registered reviews, and Epistemonikos. Kidney outcomes were reported inconsistently in older trials, so also check whether an older review used an outcome definition that is no longer standard. 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.
- Exercise programmes during haemodialysis: physical function and quality of life
- Treatments for chronic kidney disease-associated itch
- Timing of kidney replacement therapy in acute kidney injury across different definitions
Questions
How do I check whether a nephrology meta-analysis already exists?
Search PubMed with the systematic review filter and the Cochrane Library, where the Cochrane Kidney and Transplant group publishes many reviews. Then check PROSPERO for registered reviews and Epistemonikos, and note when the newest review last searched.
Is eGFR a good outcome for a meta-analysis?
It is easy to pool, but it is a surrogate. The strongest reviews also report kidney failure, even if few trials had enough events, and explain why short-term changes in eGFR may not reflect long-term kidney health.
Can I include observational studies?
For questions about prognosis or harm, yes, but say how you handled confounding and keep them apart from randomized trials in the analysis. For treatment effects, randomized trials are the main evidence.
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.