Adjunctive Azithromycin in Obese Patients Undergoing Unscheduled C-Sections

In 2018, after Cleveland Clinic integrated a standard dose of azithromycin into for women undergoing unscheduled cesarean delivery to reduce the risk of infectious complications, Maeve Hopkins, MD, decided to study whether the 500 mg dose provided adequate perioperative prophylaxis in obese patients.

“With our standard prophylaxis antibiotic cefazolin, we give different doses based on body weight, increasing the dose for obese patients,” says Dr. Hopkins, a physician in the Department of Obstetrics and Gynecology. “I wondered whether the standard azithromycin dose might have different efficacy based on larger body weight.”

Study design and key findings

Postoperative wound infection is one of the most common complications following cesarean delivery, occurring in up to 12% of women undergoing unscheduled C-sections with standard pre-incision prophylaxis (cefazolin). The 2016 Cesarean Section Optimal Antibiotic Prophylaxis (C/SOAP) study published in the New England Journal of Medicine indicated that adding 500 mg of intravenous azithromycin to the standard prophylaxis reduced the risk of infectious complications. The mean BMI of patients in the randomized controlled trial was 35.5 kg/m2.

The C/SOAP study influenced Cleveland Clinic’s decision to add azithromycin to its order set and led to Dr. Hopkins’ follow-up research project. The retrospective study, published in the American Journal of Perinatology, included 1,273 patients with a BMI ≥ 40 kg/m2 who underwent unscheduled cesarean delivery at Cleveland Clinic from Jan. 1, 2017, to Jan. 1, 2020.

Dr. Hopkins and her colleagues analyzed data for 303 patients in the pre-azithromycin order set group and 970 in the post-azithromycin order set group, reviewing composite wound complications that included clinical diagnosis of wound seroma, hematoma and superficial or deep wound infection.

“When looking at the composite wound outcomes, it appeared that patients who received a standard dose of azithromycin had lower risk of infectious complications related to their unscheduled C-section deliveries,” says Dr. Hopkins. The study also showed that standard-dose azithromycin reduces readmission/unscheduled visits in patients with class III obesity.

Clinical implications

Research projects such as the one conducted by Dr. Hopkins help ensure that Cleveland Clinic provides safe care for all patients.

“In obstetrics, we take patients as they come – at their baseline of health – and do the absolute best we can medically to achieve the best outcome,” says Dr. Hopkins. “Confirming findings from the big C/SOAP study in a high-risk group of patients with BMI over 40 helps reassure us that we are giving quality care to patients of all sizes.”