Background
Well-designed trials are of paramount importance in improving the delivery of care to patients with kidney disease. However, it remains unknown whether contemporary clinical trials within nephrology are of sufficient quality and quantity to meet this need.
Study Design
Systematic review.
Setting & Population
Studies registered with ClinicalTrials.gov.
Selection Criteria for Studies
Interventional (i.e., non-observational) studies (both randomized and nonrandomized) registered between October 2007 and September 2010 were included for analysis. Studies were independently reviewed by physicians and classified by clinical specialty.
Predictor
Nephrology versus cardiology versus other trials.
Outcomes
Select clinical trial characteristics.
Results
Of the 40,970 trials overall, 1054 (2.6%) were classified as nephrology. The majority of nephrology trials were for treatment (75.4%) or prevention (15.7%), with very few diagnostic, screening, or health services research studies. Most nephrology trials were randomized (72.3%), including 24.9% that included a single study group, 64.0% that included parallel groups, and 9.4% that were crossover trials. Nephrology trials, compared with 2264 cardiology trials (5.5% overall), were more likely to be smaller (64.5% versus 48.0% enrolling ≤100 patients), phase I-II (29.0% versus 19.7%), and unblinded (66.2% versus 53.3%; P<0.05 for all). Nephrology trials were also more likely than cardiology trials to include a drug intervention (72.4% versus 41.9%) and were less likely to report having a data monitoring committee (40.3% versus 48.5%; P<0.05 for all). Finally, there were few trials funded by the National Institutes of Health (3.3%, nephrology; 4.2%, cardiology).
Limitations
Does not include all trials performed worldwide, and frequent categorization of funding source as university may underestimate NIH support.
Conclusions
Critical differences remain between clinical trials in nephrology and other specialties. Improving care for patients with kidney disease will require a concerted effort to increase the scope, quality, and quantity of clinical trials within nephrology.