Clinical outcomes of campylobacteriosis: a case series analysis of hospitalisations associated with the Havelock North Campylobacter outbreak

AIM: In August 2016, a large waterborne campylobacteriosis outbreak occurred in Havelock North, New Zealand. This analysis describes the clinical complications of cases admitted to hospital as a result of acute infection, identifies risk factors for hospitalisation and compares deaths between hospitalised and non-hospitalised cases. Hospital admissions with post-infectious sequelae were excluded as they are the subject of a separate analysis. METHODS: A case series analysis was undertaken by reviewing the electronic medical records of 933 residents of Hawke's Bay District Health Board with probable and confirmed campylobacteriosis linked to the Havelock North Campylobacter outbreak. RESULTS: A total of 67 hospital admissions, among 58 individuals, are described. Pre-existing comorbidity and advanced age were significant risk factors for hospital admission in univariate analysis. Dehydration (74.1%), electrolyte imbalance (35.8%) and acute kidney injury (27.6%) were common among hospitalised cases. The proportion of hospitalised cases that died within one year was significantly higher when compared to deaths among non-hospitalised cases (OR 5.0, 95% CI: 2.3-10.7), although this trend was not statistically significant after adjusting for age and comorbidity (OR 2.3, 95% CI: 0.96-5.3). CONCLUSIONS: This study highlights the serious health impacts that occurred from a campylobacteriosis outbreak of this magnitude.