Catheter-tip colonization as a surrogate end point in clinical studies on catheter-related bloodstream infection: how strong is the evidence?

In clinical trials, the incidence of catheter-tip colonization (CTC) is frequently used as a surrogate end point for the incidence of catheter-related bloodstream infection (BSI). It is not clear whether the correlation between CTC and catheter-related BSI is good. We searched the MEDLINE database and conducted a literature search for the years 1990-2002 and retrieved 29 studies (with a total of 60 study groups) with incidence data on predefined CTC and catheter-related BSI definitions. A good linear correlation between CTC and catheter-related BSI was found (r=0.69; r2=0.48; P<.001). The data from the medical literature about catheter-related infection seem to support the use of CTC as a surrogate end point for catheter-related BSI. In evaluations of clinical interventions or new techniques for the prevention of catheter-related BSI, investigation of the prevention of CTC seems to be a logical first step.