Presentation on theme: "The Effect of Serotype on Early and Late Mortality in Invasive Pneumococcal Disease in Hull and East Yorkshire 2002-2009 Chloe Walsh ACF infectious diseases."— Presentation transcript:
1The Effect of Serotype on Early and Late Mortality in Invasive Pneumococcal Disease in Hull and East YorkshireChloe WalshACF infectious diseasesMSc by thesis (part time)Supervisors: Dr Gavin Barlow, Dr Victoria Allgar
2What is Invasive Pneumococcal Disease? Pneumococcus is a gram positive bacterium that colonises the upper respiratory tract.Can become pathogenicInvasive Pneumococcal disease(IPD) is diagnosed whenPneumococcus is isolated froma normally sterile site.
3Why is IPD important?Around 2 million deaths are attributed to Pneumococcus globally per annumLocal study of IPD (Elston et al) found that 21.6% of patients died within 30 days of diagnosis36.8% of patients died within one year of diagnosis.Overall incidence of IPD of 11.8/ in 2002, increasing to 16.4/ by 2009
4IPD and Mortality Traditionally considered an acute illness Both pneumonia and sepsis have been associated with longer term mortalityDeterminants of this poorer long term outcome are not fully understood
5Serotypes Over 90 serotypes based on polysaccharide capsule “Invasive” versus “colonising”“Colonising” serotypes associated with poorer outcomesCapsule is target for vaccination
6Role of serotypeMeta-analysis has shown 1, 7F and 8 to be associated with better outcomes (“low severity”)3, 6A, 6B, 9N and 19F are (“high severity”)Although relationship to acute deaths has been studied, whether serotypes influence longer term mortality has not been established
7Methods Retrospective cohort All patients admitted to Hull Royal Infirmary or Castle Hill with IPD between 2002 and 2009 identifiedSerotype recorded where available and classified as “low severity”, “high severity” or “other”Demographic data also collected (sex, age at time of sample and index of multiple deprivation (IMD) score)
8Results N=553 Mean age 59.4 46% female Mean IMD 31.9 (range 1.6-81.5) Overall mortality at 30 days, 1 year and 2 years respectively 22.9%, 36.9% and 42.4% respectively
9ResultsMortality in patients with lower risk serotypes (1, 7F and 8) (n=123) was lower than with higher risk serotypes (3, 6a, 6B, 9N and 19F) (n=75); 11.4% versus 21.3% at 30 days (p =0.012).At 1 and 2 years p<0.001Increasing age (p<0.001) and male sex (p=0.003) also associated with increased mortality at 2 years.
10Mortality rate at 30 days, 1 year and 2 years by Serotype Group
12ConclusionsIPD is associated with increased mortality up to 2 years following infectionInfection with a “high severity” serotype is associated with worse outcomeNo evidence that infection with “low severity” serotype is associated with increased long term mortality
13DiscussionPossible that patients who have infections caused by “high severity” serotypes have a lower barrier to infection due to underlying co-morbid illnessOngoing work to further establish factors associated with poor long term outcomesImportant to understand the role of serotype for future vaccine development