Staffing level: a determinant of late-onset ventilator-associated pneumonia.

A body of knowledge exists to suggest an association between nurse staffing and adverse patient outcomes. Hugonnet and colleagues add further evidence by linking nurse staffing to late-onset ventilator-associated pneumonia. Discussed are a number of concerns surrounding the analytic component of this study, including the construction of variables and the statistical models. The authors' estimation that hospitals maintaining a nurse-to-patient ratio above 2.2 could decrease the risk of health care associated infections is based on findings that are potentially biased and unrealistic.