LAUSR

BACKGROUND A considerable proportion of surgical site infections (SSI) could be prevented by surveillance. The study aimed to compare the cost-effectiveness of 3 methods of SSI surveillance: Inpatient, phone, and out-patient clinic (OPC); to ensure that the risk of SSI is independent from loss-to-follow-up in phone and OPC surveillances, and to determine the reliability of phone surveillance. METHODS A cohort of 351 surgical patients were followed by 3 different surveillance methods: inpatient, follow-up in OPC and over the phone. Costs of nurse time and phone calls were expressed in 2019 USD. Effectiveness of surveillance was assessed using number of detected SSIs. RESULTS Phone surveillance was more cost-effective than OPC surveillance. Compared to inpatient surveillance, the OPC method costs USD 15.6 per extra detected SSI, whereas the phone method costs only USD 4.6 In phone and OPC surveillances, the risk of SSI was independent of loss-to-follow-up. However, the higher rate of SSI among OPC attendees raises the suspicion that the incidence of SSI estimated by OPC surveillance could be biased upward. Phone surveillance was reliable with high sensitivity and specificity. CONCLUSIONS Phone surveillance was a reliable cost-effective method. Inpatient surveillance was less effective, but it still can be used to detect severe SSI at low cost. While out-patient-clinic surveillance had the highest cost, the incidence estimated by it might be biased upward.