Long-term trends in incidence and mortality in Staphylococcus aureus bacteraemia; a retrospective population-based study from Central Norway 1996-2022

Objectives This study aims to examine changes in incidence and mortality in Staphylococcus aureus bacteraemia (SAB) over time and between sexes, describe clinical characteristics and assess their associations with 30-day mortality. Methods We included 837 first-time SAB episodes from 1996 through 2022 in patients aged 18 years or older recorded in the Nord-Trøndelag Hospital Trust Sepsis Registry. Logistic regression was used to investigate time trends and associations with mortality. The study period was divided into early- (1996–2004), mid- (2005–2013) and late- (2014–2022) periods, and results are reported for each period and overall. Results The incidence of SAB increased from 20.0 to 40.3 per 100 000 person years from the early- to the late periods, with males accounting for 522 (62.4%) of all cases. Mortality decreased from 22.6% to 19.0% in males and 29.2% to 20.0% in females. Higher age, malignancy, congestive heart failure, pulmonary infection focus, and unknown focus were associated with increased 30-days mortality. Conclusion The incidence rate of SAB increased significantly from 1996 to 2022, with a consistently higher rate in males compared to females. While the highest mortality rate was observed in females in the earliest period, the mortality rate declined more in females than males, resulting in similar rates between the sexes in the last period. This decline occurred despite an ageing patient population and a stable burden of comorbidities. With the exception of age, none of the variables associated with increased or decreased mortality changed significantly over time.