Outcomes of Clostridium difficile Infection caused by the NAP1/BI/027 strain vs. Non Hypervirulent Strains: A Propensity Score Analysis.
difficile infection (CDI) is a serious cause of infectious diarrhea in the United
States. The new epidemic of CDI has been associated with the emergence of the
NAP1/BI/027 strain, which has been linked to severe disease outcomes. It is unknown
whether having the NAP1/BI/027strain as the cause of CDI is associated with increased
morbidity and mortality, independent of the... read moreeffect of host risk factors. This was a post
hoc analysis of two phase 3 clinical trials comparing fidaxomicin vs. vancomycin for
treatment of CDI. A propensity score for patients with CDI caused by the NAP1/BI/027
strain versus patients who did not have the strain was calculated. The outcomes assessed
were disease severity, clinical cure and disease recurrence. Three different
applications of the propensity score were used to assess disease outcomes: logistic
regression (using quintiles of propensity score), matching and inverse probability
weighting. Of the 792 patients with typed strains, 283 (35%) patients had the
NAP1/BI/027 strain. Based on univariate analysis, patients with the NAP1/BI/027 strain
were older, more likely to have a chronic disease and be exposed to antibiotics within
two weeks of study enrollment. After controlling for the quintile of propensity, having
the NAP1/BI/027 strain as the cause of CDI was associated with decreased cure (OR 0.42,
95% CI 0.27-0.64) as compared with not having the strain. However, having the
NAP1/BI/027 strain as the cause for disease was not associated with disease severity (OR
1.08; 0.72-1.63). There was a trend towards higher disease recurrence rates among the
patients with the NAP1/BI/027 strain (OR 1.33; 95% CI 0.86-2.04). After propensity score
adjustment, patients with the NAP1/BI/027 strain do not have more severe disease than
patients without the strain but appear to have reduced cure rates, regardless of
underlying risk factors for disease. Patients with the NAP1/BI/027 strain as the cause
of CDI may be at higher risk of recurrence compared to patients without the
Thesis (M.S.)--Tufts University, 2013.
Submitted to the Dept. of Clinical & Translational Science.
Advisor: David Snydman.
Committee: Yoav Golan, and Robin Ruthazer.
Keyword: Medicine.read less