Racial disparities in the frequency of patient safety events: results from the National Medicare Patient Safety Monitoring System.

BACKGROUND: Although there is extensive evidence of racial disparities in processes and outcomes of medical care, there has been limited investigation of disparities in patient safety.
OBJECTIVE: To determine whether there are racial disparities in the frequency of adverse events studied in the Medicare Patient Safety Monitoring System. DESIGN AND
SUBJECTS: Abstraction of 102,623 randomly selected charts from hospital discharges of non-Hispanic white and black Medicare patients between January 1, 2004 and December 31, 2007 to assess frequency of patient safety events in 4 domains: general (pressure ulcers and falls), selected nosocomial infections, selected procedure-related adverse events, and adverse drug events due to anticoagulants and hypoglycemic agents. MEASURES: Racial disparities in risk of patient safety events, and differences in adverse event rates among hospital groups stratified by percentage of black patients.
RESULTS: Blacks had higher adjusted risk than whites of suffering one of the measured nosocomial infections (1.34; 95% confidence interval, 1.17-1.55; P < 0.001) and one of the measured adverse drug events (1.29; 95% confidence interval, 1.19-1.40; P < 0.001). After adjustment for patient and hospital factors, patients in hospitals with the highest percentages of black patients were at increased risk of experiencing one of the measured nosocomial infections (1.9% vs. 1.5%; P < 0.001) and adverse drug events (8.7% vs. 7.8%; P < 0.01).
CONCLUSIONS: Hospitalized blacks are at higher risk than whites of experiencing certain patient safety events. In addition, hospitals serving high percentages of black patients have higher risk-adjusted rates of selected patient safety events.