A Cochrane review of the evidence examined the effects of replacing doctors with nurses in hospital settings and analyzed 82 randomized trials involving more than 28,000 patients in 20 countries. A meta-analysis concluded that there was "little to no difference" between nurse-led care and physician-led care on critical outcomes including mortality, quality of life, self-efficacy and patient safety. The studies examined four types of interventions in different clinical settings where nurses of different ages replaced doctors in specialties such as cardiology, diabetes, cancer, obstetrics/gynecology and rheumatology. However, experts have warned that this study has critical flaws and its results are problematic. The researchers came from Ireland, the UK and Australia and their findings were presented as a Cochrane Evidence Review.