Post-discharge surgical site surveillance: does patient education improve reliability of diagnosis?

Post-discharge surgical infection surveillance by patients remains an integral part of many infection control programmes despite proven unreliability. We attempted to improve the validity of patient recognition of signs and symptoms of wound infection and post-discharge postal questionnaire responses through specific education prior to discharge. In total, 588 patients were studied after random assignment into two intervention groups, one of which received relevant education. Both groups were followed for four weeks post-operatively, with features of infection assessed weekly by experienced infection control nurses (ICNs) and by patient responses to routine postal questionnaires. Those patients who received education demonstrated a significantly poorer correlation with ICN diagnosis compared to the non-educated group (Kappa 0.69 and 0.81 respectively, P=0.05). Both patient groups achieved the same sensitivity for recall (83.3%), with high specificity demonstrated by both groups [educated (93.7%); non-educated (98.1%)]. The positive predictive value was 65.2% for the educated group and 83.3% for the non-educated patient group. When infected wounds identified by patients were examined for the proportion that were overdiagnosed, the excess of SSI identified by the educated patient group was 44.4% and by the non-educated group 16.7%. These results suggest that pre-discharge education causes patients to overdiagnose clinical features of wound infection and fails to improve the validity of diagnosis. This outcome further questions the value of post-discharge infection rates obtained by patient self-assessment as a measure of quality of performance.