699 Impact of Adherence to Antibiotic Prophylaxis on Rheumatic Heart Valve Surgical Outcomes in the Northern Territory of Australia

Abstract

Background: Intramuscular Benzathine penicillin G (BPG) injection every 21-28 days to age 40 years or longer is the recommended secondary prophylaxis therapy for Rheumatic Heart Disease (RHD) surgical patients. Adherence status is highly variable. No studies have looked at the association between adherence to secondary prophylaxis and its impact on long-term surgical outcomes. Method: Of 342 Indigenous patients who underwent their primary RHD surgical procedure between 1997 and 2016, 138 had high quality data in relation to adherence to BPG. Pre-and postoperative data was collated using clinical information systems. Logistic regression was used to estimate relative risk (RR). Multivariable Survival analyses were performed using Cox Proportional Hazards model. Results: Mean follow-up time is 3.9 years (range 0-8.5 years), a total of 542.7 patient years. Improving adherence category is associated with a reduction in mortality, 0-,50%, 50-79%, 80-99% and .100% is 11 (26.8%), 2(7.7%), 6 (12.5%), 1(4.3%) respectively. Of 30 of 138 patients, who received no BPG during the study period, 9 (30%) of these died during the study period compared to 11(10 %) who received any treatment. This equated to a RR of death of 2.89 (95% CI: 1.30-6.45) p value 0.0074, for those with 0-,50%. Conclusion: Adherence to antibiotic prophylaxis improves survival outcomes of high risk RHD populations requiring valve surgery. As such significant focus is required to address system issues and barriers to improving adherence status at community and patient level. Widespread selfmanagement strategies are essential.