Factors Affecting Recurrent Staphylococcus aureus Bacteremia Among Older Patients in Rural Community Hospitals: A Retrospective Cohort Study.

Introduction Staphylococcus aureus bacteremia (SAB) poses a significant health risk, particularly among adults over 65 years old, due to age-related vulnerabilities and comorbidities. Recurrent SAB is associated with increased morbidity, prolonged hospitalizations, and higher healthcare costs, necessitating the identification of risk factors that contribute to these recurrent infections. Methods A retrospective cohort study was conducted at a rural community hospital to identify factors associated with recurrent SAB in older patients. Data were extracted from electronic medical records of patients diagnosed with SAB between April 2016 and December 2023. Multivariate logistic regression was employed to analyze the relationship between recurrent SAB and potential risk factors, including age, sex, BMI, dependency on Japanese long-term health insurance, and comorbidities. Results Among 99 patients with SAB, 36 (36.4%) experienced recurrence. Higher BMI was significantly associated with recurrent SAB (OR: 1.15, 95% CI: 1.01-1.31, p = 0.036), while dependency on long-term care was associated with a lower risk of recurrence (OR: 0.20, 95% CI: 0.06-0.64, p = 0.007). Age and sex did not show significant associations with recurrence. Conclusion This study identified higher BMI as a risk factor for recurrent SAB in older patients, while dependency on long-term care was protective. These findings highlight the need for targeted management strategies for patients with higher BMI to prevent recurrent SAB. Further research is needed to explore these associations and confirm their relevance in other clinical settings.