Intersection of sepsis, atrial fibrillation, and severe obesity: a population-based analysis in the United States

Background: Atrial fibrillation (AF) is an indicator of poor prognosis in patients with sepsis and can increase the risk of stroke and mortality. Data on the impact of severe obesity on the outcomes of sepsis complicated by AF remains poorly understood.

Methods: National Inpatient Sample (2018) and ICD-10 CM codes were used to identify the principal sepsis admissions with AF. We assessed comorbidities and outcomes of sepsis in people without obesity (BMI < 30) vs. non-severe obesity (BMI 30-35) and severe obesity (BMI > 35) cohorts. We also did a subgroup analysis to further stratify obesity based on metabolic health and analyzed the findings. The primary outcomes were the prevalence and adjusted odds of AF, AF-associated stroke, and all-cause mortality in sepsis by obesity status. Multivariable regression analyses were adjusted for patient- and hospital-level characteristics and comorbidities.

Results: Our main analysis showed that of the 1,345,595 sepsis admissions, the severe obesity cohort was the youngest (median age 59 vs. non-severe 64 and people without obesity 68 years). Patients with obesity, who were often female, were more likely to have hypertension, diabetes, congestive heart failure, chronic pulmonary disease, and chronic kidney disease. The crude prevalence of AF was highest in non-severe obesity (19.9%). The adjusted odds of AF in non-severe obesity (OR 1.21; 95% CI:1.16-1.27) and severe obesity patients with sepsis (OR 1.49; 95% CI:1.43-1.55) were significantly higher than in people without obesity (p < 0.001). Paradoxically, the rates of AF-associated stroke (1%, 1.5%, and 1.7%) and in-hospital mortality (3.3%, 4.9%, and 7.1%) were lowest in the severe obesity cohort vs. the non-severe and people without obesity cohorts, respectively. On multivariable regression analyses, the all-cause mortality revealed lower odds in sepsis-AF patients with severe obesity (OR 0.78; 95% CI:0.67-0.91) or non-severe obesity (OR 0.63; 95% CI:0.54-0.74) vs. people without obesity. There was no significant difference in stroke risk.

Conclusions: A higher prevalence of cardiovascular comorbidities can be linked to a higher risk of AF in people with obesity and sepsis. Paradoxically, lower rates of stroke and all-cause mortality secondary to AF in people with obesity and sepsis warrant further investigation.