Antibiotic prophylaxis beneficial in percutaneous nephrolithotomy patients

In a matched case-control study that addressed postoperative infection rates in low-risk PCNL patients, researchers from the Clinical Research Office of the Endourological Society (CROES) found a threefold lower incidence of infection in patients who received prophylactic antibiotics.

The CROES study prospectively collected data for 1 year on patients treated consecutively with PCNL who were at a low risk for postoperative infections, defined by negative preoperative urine cultures. The investigators found 5,803 patients who were treated by PCNL at 96 centers worldwide. They matched 162 low-risk patients who had received no antibiotics preoperatively 1:1 with patients who had.

Dr. Gravas and colleagues observed postoperative fever rates of 2.5% versus 7.4% (p=.04) and a mean (standard deviation) operating time of 73.0 minutes (SD=40.8) versus 79.2 (SD=38.1) minutes (p=.160) for patients with and without antibiotic prophylaxis, respectively. Statistically insignificant differences in mean (SD) length of hospital stay were observed: 4.1 days (SD=2.2) versus 3.7 days (SD=3.0) for the antibiotic and no antibiotic groups. The mean stone burden was 317 mm² versus 374.7 mm² (p=.076) for patients with and without prophylactic antibiotics, respectively.

^{Could study's size be a drawback?}

Session co-chair Viorel Bucuras, MD, PhD, of Victor Babes University of Medicine and Pharmacy, Timisoara, Romania, noted that conditions and patient characteristics were difficult to compare in a study that looked at nearly 6,000 patients from nearly 100 worldwide centers. He said that a certain uniformity was also lacking in the antibiotic protocol.

"This is the beauty but also the limitation of the global PCNL project," Dr. Gravas explained. "We did not have a common antibiotic protocol, as this was dependent upon local conditions. The choice of antibiotic was at the discretion of the treating physician, his national guidelines, known antibiotic resistance patterns, and/or the guidelines of the hospital infection committees."

Urologists who attended Dr. Gravas' presentation argued that postoperative fever was not necessarily synonymous with postoperative infection shown by a positive culture. They were concerned that the postoperative fever rate observed in the non-antibiotic patient group may well not have reflected true infections at all. Additionally, different stone types can cause fever more than others, and this information was lacking. Moreover, they argued that patients receiving prophylactic antibiotics frequently received the wrong type, begging the question whether antibiotic prophylaxis should even be routine.

"It is a fair point; however, this is the best we could derive from our database. It is more or less well agreed, though, that if you have a fever for a day of 38.5°C or higher, the physician can suspect a urinary tract infection," Dr. Gravas noted.