What Explains Hospital Variation In Antibiotic Usage?

James Baggs, PhD Division of Healthcare Quality Promotion Centers for Disease Control and Prevention Atlanta, GA

Dr. James Baggs, PhD

MedicalResearch.com Interview with:
James Baggs, PhD
Division of Healthcare Quality Promotion
Centers for Disease Control and Prevention
Atlanta, GA

Medical Research: What is the background for this study?

Dr. Baggs: The National Action Plan for Combating Antibiotic Resistance Bacteria calls for annual reporting of antibiotic use in inpatient settings as well as the identification of variations at the provider or patient level that can assist in developing interventions. Antibiotic use varies among hospitals, but some portion of that variability is related to the type of patients admitted to the hospital and other hospital characteristics. We evaluated factors in a large cohort of US hospitals that may account for inter-facility variability in antibiotic use, so that we can more appropriately monitor antibiotic use in hospitals.

Medical Research: What are the main findings?

Dr. Baggs: We utilized data from the Truven Health MarketScan Hospital Drug Database (HDD), which contains detailed administrative records, including inpatient drug utilization data based on billing records, for all patients discharged from a convenience sample of over 500 US hospitals. We retrospectively estimated days of therapy (DOT)/1,000 patient days (PDs) by year from 2006-2012, and created a multivariable model that adjusts for hospital-specific location of antibiotic use (ICU vs. other), average patient age, average patient co-morbidity score, number of hospital beds, teaching status, urban or rural location, proportion of discharges with a surgical diagnosis related code, case mix index, and proportion of patient days with an infectious disease primary ICD-9-CM discharge code. We observed that DOT varied significantly between hospitals; the 10th to 90th percentile values for hospital days of therapy ranged from 546 to 998/1,000 PDs. The variables included in our model accounted for 47-53% of the inter-facility variability, depending on year. However, nearly all of this variability was explained by two predictors: proportion of PDs with an infectious disease diagnosis code and hospital location (ICU vs. other). 

Medical Research: What should clinicians and patients take away from your report?

Dr. Baggs: Clinicians and researchers who make inter-facility comparisons of antimicrobial use should consider adjusting for the proportion of PDs with an infectious disease primary diagnosis code and the hospital location of antibiotic use. However, approximately half of inter-hospital variability in antimicrobial use remains unexplained. We hypothesize that the remaining difference may be due to variations in prescribing behavior that could be addressed through antibiotic stewardship programs. In other words, hospital clinicians in some hospitals might be prescribing more antibiotics than those in other hospitals, even though, as best we can tell, the patients these hospitals provide care for are similar.  This is likely due to inappropriate use of antibiotics in some hospitals. Inappropriate antibiotic use does not improve patient care but does increase the risk of antibiotic resistance among bacteria that infect hospitalized patients.

Medical Research: What recommendations do you have for future research as a result of this study?

Dr. Baggs: Further studies using additional years of data in the MarketScan HDD as well as other datasets containing information from different hospitals should be explored to corroborate our findings and develop methods to adjust for these factors in comparisons between facilities. In addition, further research should focus on determining if other factors may explain variations in prescribing behavior, if increased antibiotic use is related to unfavorable health outcomes in patient populations in addition to well-known outcomes such as Clostridium difficile infection and antibiotic resistance, and how antibiotic stewardship programs can be effective in reducing inappropriate antibiotic use in US hospitals.


IDWeek 2105 abstract: Factors Associated with Inter-Hospital Variability of Inpatient Antibiotic Use in a Cohort of US Hospitals

Oral Abstract Session: Antimicrobial Stewardship: Practice Variability and Interventions
Friday, October 9, 2015: 8:30 AM

James Baggs, PhD (2015). What Explains Hospital Variation In Antibiotic Usage? MedicalResearch.com