The Effects of Missed Doses of Antibiotics on Hospitalized Patient Outcomes.

Background: Missing doses of antibiotics in hospitalized patients is a well-described but inadequately recognized issue. We hypothesized that missing doses of antibiotics decreases quality of care.

Methods: Retrospective study on patients admitted to the Shock Trauma ICU from February to June 2015. Patients prescribed a multidose course of antibiotics were evaluated. A missed antibiotic dose was one ordered but never given (a completely missed dose) or a dose that was not given within an hour before or after the planned time (an off-schedule missed dose). Patient outcomes included a positive culture, ventilator, ICU and hospital length of stay (LOS), and mortality. Multiple statistical methods were used as appropriate; significance was set as P < 0.05.

Results: For the 5-mo study period, 280 patients were admitted and 200 met inclusion criteria. Eight percent of patients (16/200) did not miss any antibiotic doses, 39% (77/200) had only off-schedule doses, 2% (4/200) had only completely missed doses, and 51% (103/200) had both off-schedule and completely missed doses. For the 200 patients, 8167 doses were ordered and 2096 (26%) were missed. Adjusting for age, gender, BMI, injury severity score, and doses of antibiotics showed that those who miss doses off-schedule had longer LOS than those who do not miss doses of antibiotics. There was a significant nonlinear relationship between LOS and frequency of early (P-value = 0.02) and late (P-value = 0.01) doses.

Conclusions: To reduce length of hospital stay and optimize quality, methods to improve compliance with antibiotic dosing schedules should be investigated.