2021 Johanna Birrell

Johanna Birrell

Johanna went through medical school in Adelaide, Australia, completed basic physician training in Darwin and then migrated across the Tasman in 2018 for advanced training in general medicine and public health. After a year in Taranaki she spent 2020 in Whangarei and is now on maternity leave with her 8 week old baby, Rosie.

Epidemiology, Characteristics And Impact Of Infective Endocarditis In Northland, New Zealand

Aims: To define the epidemiology, microbiology, clinical features and healthcare impact of infective endocarditis (IE) in Northland.

Methods: Health records of patients treated for IE in Northland between 1 January 2010 and 31 December 2019 were analysed retrospectively. Patients were identified through hospital clinical coding systems. Cases were classified using the Modified Duke Diagnostic Criteria.

Results: 140 (97 definite and 43 possible) cases of IE were identified. 104 patients were male (74%). Median age at diagnosis was 70 years. 102 patients (73%) were of European ethnicity and 37 (26%) were Māori. The incidence of IE in Northland was 8.5 per 100,000-person-years. The highest-risk group were Māori aged 80-84 years, with an incidence of 72.9 cases per 100,000-person-years.

Risk factors included prosthetic heart valves (n=62, 44%), congenital valve disease (n=25, 18%) and rheumatic heart disease (n=19, 14%). Causative organisms included streptococcal species (n=60, 43%), Staphylococcus aureus (n=42, 23%) and enterococci (n=22, 16%). Blood cultures were positive in 90% of cases. Sensitivity of transthoracic echocardiography compared to transoesophageal echocardiography in detecting vegetations was 38%.

Complications included stroke (n=33, 24%), systemic embolism (n=53, 38%), congestive heart failure (n=42, 30%) and paravalvular abscess (n=19, 14%).

Mean length of hospitalisation was 27 days, with a total combined hospital stay of 3,809 days. 96 patients (69%) underwent inter-hospital transfer. 57 (41%) required intensive care. 46 (33%) received cardiac surgical intervention. The mortality rate at 6 weeks after diagnosis of IE was 18% and at 1 year was 24%. An estimated $6,560,470 was spent on direct patient care.

Conclusions: IE is causing substantial morbidity and mortality in Northland and consuming considerable healthcare resources. A high index of suspicion for IE and low threshold for TOE is recommended. A high proportion of cases were caused by odontogenic organisms and preventative investment in dental care has the potential to be cost-effective.