Hospital Acquired C. diff Infections Increase Both Length of Stay and Mortality Interview with:
Esther van Kleef
London School of Hygiene and Tropical Medicine,
London, UK

Medical Research: What are the main findings of the study?

Response:  Existing evidence reveals a wide variation in estimated excess length of hospital stay (LoS) associated with healthcare-acquired C. difficile infection (HA-CDI), ranging from 2.8 to 16.1 days. Few studies considered the time-dependent nature of healthcare-acquired C. difficile (i.e. patients that spent a longer time in hospital have an increased risk of infection), and none have considered the impact of severity of healthcare-acquired C. difficile on expected delayed discharge. Using a method that adjusted for this so-called time-dependent bias, we found that compared to non-infected patients, the excess length of stay of severe patients (defined by increased white blood cell count, serum creatinine, or temperature, or presence of colitis) was on average, twice (11.6 days; 95% CI: 3.6-19.6) that of non-severe cases (5.3 days; 95% CI: 1.1-9.5). However, severely infected patients did not have a higher daily risk of in-hospital death than non-severe patients. Overall, we estimated that healthcare-acquired C. difficile prolonged hospital stay with an average of ~7 days (95% CI: 3.5-10.9) and increased in-hospital daily death rate with 75% (Hazard Ratio (HR): 1.75; 95% CI: 1. 16 – 2.62).

Medical Research: What was most surprising about the results?

Response:  Two earlier studies that accounted for time-dependent bias showed contradicting results (i.e. a Canadian study found an excess length of stay of 6 days, whereas an Australian study concluded that HA-CDI did not prolong length of stay). We hypothesised that such difference in findings might relate to heterogeneity in prevalence of severity of the infection among the different hospital settings, as well as to differences in case-mix. However, our results revealed that both patients with severe and non-severe infection had an excess hospital stay. Moreover, when we adjusted our results for age and co-morbidity, both younger and older healthcare-acquired C. difficile patients had an increased average length of stay . The same was true for patients with different co-morbidity scores.

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

Response: A majority of the published estimates regarding additional length of stay due to healthcare-acquired infections (HAI) are an overestimate, as the earlier mentioned time-dependent bias has not been considered. In addition, the impact of healthcare-acquired C. difficile can vary between settings. When quantifying the health and economic burden of hospital-onset of healthcare-acquired C. difficile, this should be accounted for.

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

Response: In order to gain further understanding of the identified variation in the impact of healthcare-acquired C. difficile we urge for additional analysis, using similar methods, of large, linked individual patient-level data, which will allow for identification of a wide range of factors predicting the potential burden of healthcare-acquired C. difficile in addition to severity of the infection, such as causative PCR ribotype, the patient’s treatment specialty, previous hospital admissions and history of CDI.



Excess length of stay and mortality due to Clostridium difficile infection: a multi-state modelling approach

van Kleef, E. et al. Journal of Hospital Infection