Epidemiology of and Surveillance for Postpartum Infections

Deborah S. Yokoe, Cindy L. Christiansen, Ruth Johnson, Kenneth Sands, James Livingston, Ernest S. Shtatland, Richard Platt
2001 Emerging Infectious Diseases  
We screened automated ambulatory medical records, hospital and emergency room claims, and pharmacy records of 2,826 health maintenance organization (HMO) members who gave birth over a 30-month period. Fulltext ambulatory records were reviewed for the 30-day postpartum period to confirm infection status for a weighted sample of cases. The overall postpartum infection rate was 6.0%, with rates of 7.4% following cesarean section and 5.5% following vaginal delivery. Rehospitalization; cesarean
more » ... ery; antistaphylococcal antibiotics; diagnosis codes for mastitis, endometritis, and wound infection; and ambulatory blood or wound cultures were important predictors of infection. Use of automated information routinely collected by HMOs and insurers allows efficient identification of postpartum infections not detected by conventional surveillance. The epidemiology of postpartum infections has not been well characterized. In part this is because of the limitations of surveillance systems, which usually monitor infections that are recognized during hospitalization. Most postpartum and nonobstetrical postsurgical infections, however, occur after hospital discharge (1-3). Decreasing lengths of hospital stay may further compromise detection of these infections. Several methods for postdischarge surveillance of postpartum infections have been evaluated. Hulton et al. (1) used physician questionnaires for postdischarge surveillance of patients undergoing cesarean section. With only inpatient surveillance, 59% of postpartum infections they ultimately detected would not have been identified. The overall infection rate after postdischarge surveillance was implemented was fourfold higher than the previous rate (6.3% vs. 1.6%). Holbrook et al. (2) used patient self-administered questionnaires to conduct large-scale, routine postdischarge surveillance following vaginal delivery or cesarean section. Despite a modest return of questionnaires, self-reported questionnaire results identified twice as many apparent postpartum infections (4% infection rate) as did concurrent prospective in-hospital surveillance. Only 48% of reported maternal infections, however, were confirmed by questionnaires to the patients' physicians. Sands et al. (3) evaluated the use of automated ambulatory diagnosis, testing, and pharmacy code screening combined with discharge diagnoses to identify surgical site infections in nonobstetric patients undergoing surgery. They found that ambulatory code screening was a sensitive method for detecting patients with surgical site infections and that 84% occurred after hospital discharge. Of the postdischarge surgical site infections, most (63%) were diagnosed and treated entirely in the ambulatory setting. In addition, patient and surgeon questionnaires had low sensitivities (28% and 15%, respectively) for identifying postdischarge infections. Routine surveillance for nosocomial infections is recommended by the Centers for Disease Control and Prevention and required by the Joint Commission on Accreditation of Healthcare Organizations, with the goal of using this information to compare infection rates over time and between institutions and to guide the allocation of resources towards improvements most likely to result in reduced infection rates. In this study, we used the inpatient and outpatient data collected by a health maintenance organization (HMO) to identify postpartum infections and describe the epidemiology of these infections. Methods The study population consisted of all women who had a vaginal delivery or cesarean section at Brigham and Women's Hospital from January 1, 1993, to June 30, 1995, and who received postpartum care at Harvard Pilgrim Health Care (HPHC)/Harvard Vanguard Medical Associates (HVMA) centers with automated full-text ambulatory medical records. HPHC is a multimodel health maintenance organization that included a staff model division (now a multispecialty group practice, HVMA) with approximately 300,000 members in the greater Boston area at the time of the study. Brigham and Women's Hospital is the most active obstetrical facility for these members. HMO data included three sources: an extensively automated ambulatory record, pharmacy dispensing data, and administrative claims for hospital, emergency room, and other care delivered outside the health center. The automated ambulatory medical record system (4) used standard-
doi:10.3201/eid0705.010011 fatcat:u5k2hadqjngo5cjtke3fwtdsjm