Quasiexperimental study of the effects of antibiotic use, gastric acid-suppressive agents, and infection control practices on the incidence of Clostridium difficile-associated diarrhea in hospitalized patients

Abstract

The objective of this study was to evaluate the effects of antimicrobial drug use, gastric acid-suppressive agent use, and infection control practices on the incidence of Clostridium difficile-associated diarrhea (CDAD) in a 426-bed general teaching hospital in Northern Ireland. The study was retrospective and ecological in design. A multivariate autoregressive integrated moving average (time-series analysis) model was built to relate CDAD incidence with antibiotic use, gastric acid-suppressive agent use, and infection control practices within the hospital over a 5-year period (February 2002 to March 2007). The findings of this study showed that temporal variation in CDAD incidence followed temporal variations in expanded-spectrum cephalosporin use (average delay = 2 months; variation of CDAD incidence = 0.01/100 bed-days), broad-spectrum cephalosporin use (average delay = 2 months; variation of CDAD incidence = 0.02/100 bed-days), fluoroquinolone use (average delay = 3 months; variation of CDAD incidence = 0.004/100 bed-days), amoxicillin-clavulanic acid use (average delay = 1 month; variation of CDAD incidence = 0.002/100 bed-days), and macrolide use (average delay = 5 months; variation of CDAD incidence = 0.002/100 bed-days). Temporal relationships were also observed between CDAD incidence and use of histamine-2 receptor antagonists (H2RAs; average delay = 1 month; variation of CDAD incidence = 0.001/100 bed-days). The model explained 78% of the variance in the monthly incidence of CDAD. The findings of this study highlight a temporal relationship between certain classes of antibiotics, H2RAs, and CDAD incidence. The results of this research can help hospitals to set priorities for restricting the use of specific antibiotic classes, based on the size-effect of each class and the delay necessary to observe an effect.

FIG. 1.

Monthly CDAD incidence versus use of selected antibiotic classes and H2RAs, Antrim Area Hospital, February 2002 to March 2007 (thick line, CDAD, number of cases/100 bed-days, 5-month moving average, left y axis; thin line, antimicrobial use and H2RAs, DDDs/100 bed-days, 5-month moving average, right y axis). (A) Expanded-spectrum cephalosporins; (B) broad-spectrum cephalosporins; (C) fluoroquinolones; (D) amoxicillin-clavulanic acid; (E) macrolides; (F) H2RAs.

FIG. 2.

Monthly CDAD incidence (solid line) and monthly sum of the lagged explanatory variables with their respective coefficients (dashed line) as identified in the multivariate time-series analysis model: expanded-spectrum cephalosporin use, broad-spectrum cephalosporin use (lag of 2 months), fluoroquinolone use (lag of 3 months), amoxicillin-clavulanic acid use, H2RA use (lag of 1 month), and macrolide use (lag of 5 months), Antrim Area Hospital, February 2002 to March 2007.