Objective: To critically review the existing evidence on interventions aimed at reducing errors in health care delivery.
Design: Systematic review of randomized trials on behavioral, educational, informational and management interventions relating to medical errors. Pertinent studies were identified from MEDLINE, EMBASE, the Cochrane Clinical Trials Registry, and communications with experts.
Setting: Both inpatients and outpatients qualified. No age or disease restrictions were set.
Measurements: Outcomes were medical errors, including medication, prescription, and diagnostic errors, and excluding preventive medicine errors and simple ordering of redundant tests.
Main results: Thirteen randomized studies qualified for evaluation. The trials varied extensively in their patient populations (mean age, 2 weeks to 83 years), study setting, definition of errors, and interventions. Most studies could not afford masking and rigorous allocation concealment. In 9 of 13 studies, error rates in the control arms were very high (10% to 63%), and large treatment benefits from the studied interventions were demonstrated for the main outcome. Interventions were almost always effective in a sample of 24 nonrandomized studies evaluated for comparison. Actual patient harm from serious errors was rarely recorded.
Conclusions: Medical errors were very frequent in the studies we identified, arising sometimes in more than half of the cases where there is an opportunity for error. Relatively simple interventions may achieve large reductions in error rates. Evidence on reduction of medical errors needs to be better categorized, replicated, and tested in study designs maximizing protection from bias. Emphasis should be placed on serious errors.