Background Infectious endocardits (IE) is a rare condition associated with high morbidity and mortality. IE develops as a result of a complex interaction between the vascular endothelium, haemostatic mechanisms, the immune system and exposure to the causative microorganism. Historically cardiologists have utilised prophylactic antibiotics to cover procedures known to cause bacteraemia such as dental surgery to prevent IE. However, this practice was without evidence base and its efficacy questioned. In 2008 NICE CG64 was published advocating a radical change in practice, recommending cessation of chemoprophylaxis for the prevention of IE. In this study we aim to assess the impact of NICE CG 64 in Wales.

Methods Chemoprophylaxis was most commonly prescribed in the form of a single 3 g oral dose of Amoxicillin or a 600 mg oral dose of Clindamycin. We obtained data of all prescriptions for either Amoxicillin 3 g or Clindamycin 600 mg in Wales from 2001 to 2012. We obtained data on diagnosis of IE including the causative microorganism from PEDW database (Patient Episode Database for Wales) via SAIL databank (Secure Anonymised Information Linkage) to assess the impact of NICE CG64. Previous studies have suggested an upward trend in the incidence of IE prior to the introduction of NICE CG64. We therefore performed analysis of our data using a Poisson regression model with identity link function to correct for any trend in our data.

Results Prescriptions of Amoxicillin 3 g and Clindamycin 600 mg reduced by 77% and 92% (p < 0.001) respectively confirming at least partial adoption of NICE CG64. There was a non-significant increase in total numbers of cases of IE seen after 2008 (p = 0.135) and a significant increase in IE caused by oral streptococcus (p = 0.028). When correction was performed to adjust for the upward trend seen prior to NICE CG64 in 2008 the increase in IE caused by oral streptococcus ceased to be significant.

• Download figure
• Open in new tab
• Download powerpoint

Abstract 98 Figure 1

• Download figure
• Open in new tab
• Download powerpoint

Abstract 98 Figure 2

Conclusion The reduction in antibiotic prescriptions seen after 2008 provides evidence that NICE CG64 is being followed in Wales. NICE CG64 accepted that patients who had previously received chemoprophylaxis may continue this practice which may explain the number of prescriptions seen following 2008. Alternatively practitioners may be following international guidance from AHA 2007 and ESC 2009 that continue to recommend chemoprohylaxis in high risk patients. Despite the major change in prescribing of chemoprophylaxis observed we only identified a gradual, non-significant increasing trend in the incidence of IE. This trend may be explained by increasing population size and improved diagnostics. There was no significant deviation in this linear trend with the introduction of NICE CG64 in 2008 providing support that the cessation of chemoprophylaxis has not resulted in a large increase in the incidence of IE over a four year period.