WASHINGTON — The use of scheduled narcotic analgesics delayed the time to diagnosis of Clostridium difficile infection and also was associated with a greater risk of both severe and refractory infection in a study that involved more than 21,000 hospitalized patients.
Narcotic analgesics have antimotility effects similar to those of antiperistaltics, which have been shown to increase the risk of complications associated with C. difficile infection (CDI).
Although this 2-year retrospective cohort study did not show an increase in the overall risk of developing CDI among hospitalized patients who were given narcotics, the findings of delayed diagnosis and increased severity suggest that if possible, these agents should be withheld from patients with suspected or proven CDI and those who may be at high risk, Andrea L. Mora, Pharm.D., said at the jointly held annual Interscience Conference on Antimicrobial Agents and Chemotherapy and the annual meeting of the Infectious Diseases Society of America.
The study population included 21,358 adult patients admitted to St. Luke's Episcopal Hospital, Houston, between August 2005 and April 2007 who had received previous broad-spectrum systemic antibiotics. Of those, 241 developed CDI while in the hospital, and of this group, 123 had been in the hospital for more than 48 hours at onset of diarrhea (considered hospital-acquired). Compared with the 21,117 who did not develop CDI, the 123 who developed hospital-acquired CDI were significantly older (67.7 vs. 62.5 years), had longer lengths of stay (24 vs. 9.2 days), and had longer stays in intensive care (10.8 vs. 3.1 days).
The use of multiple broad-spectrum antibiotics was greater among those who developed CDI than among those who did not, including cefepime (55.3% vs. 20.5%), ceftriaxone (30.1% vs. 18%), meropenem (17.9% vs. 4.5%), and piperacillin/tazobactam (32.5% vs. 15%). The treatment of CDI included metronidazole in 90.2% of the 123 patients who were hospitalized 48 hours or longer and in 92.1% of all 241 CDI patients; vancomycin was used in 18.9% and 24.5%, respectively, said Dr. Mora, who is now with the South Texas Veterans Health Care System, San Antonio. Dr. Mora completed this study during her residency training at St. Luke's Episcopal Hospital.
Narcotics were used in 51.2% of the 123 CDI patients hospitalized 48 hours or longer at onset, compared with 49.3% of the 21,117 hospitalized patients without CDI, a nonsignificant difference. However, the diagnosis of CDI was significantly delayed among those who received narcotics—17.0 days from admission to the first positive C. difficile test, compared with 7.9 days among those who did not receive narcotics—even after researchers controlled for age, antibiotic use, and sex.
The reason for this isn't entirely clear, but it is believed that the constipation induced by the narcotics may mask the diarrhea that is the most characteristic symptom of CDI infection. Thus, patients may be infected but don't get tested as early as those who experience diarrhea, Dr. Mora said in an interview.
Severe CDI was also significantly more likely among those receiving narcotics (61.5% vs. 40.4%), as was refractory CDI (20% vs. 10.4%). These differences were not associated with age, sex, ethnicity, antibiotic use, or ICU status.
“We believe these results are significant because minimizing these risk factors is an important part of managing CDI,” Dr. Mora said.
Dr. Mora stated that she had no disclosures.