One size does not fit all in severe infection: obesity alters outcome, susceptibility, treatment, and inflammatory response

Abstract

IntroductionObesity is an increasingly common comorbidity in critically ill patients. Whether obesity alters sepsis outcome, susceptibility, treatment, and response is not completely understood.MethodsWe conducted a retrospective analysis comparing three group of septic shock patients based on the intervals of actual body mass index (BMI) in patients enrolled in the VASST (Vasopressin and Septic Shock Trial) cohort. Primary outcome measurement was 28-day mortality. We tested for differences in patterns of infection by comparing the primary site of infection and organism. We also compared the treatments (fluids and vasopressors) and inflammatory response, measuring adipose tissue-related cytokine concentrations (interleukin [IL]-6, monocyte chemotactic protein [MCP]-1, tumor necrosis factor [TNF]-α, and resistin) in plasma in a subset of 382 patients. Of the 778 patients in VASST, 730 patients who had body weight and height measurements were analyzed. Patients with BMI <25 kg/m2 (n = 276) were grouped as a reference and compared to 'overweight' (25< BMI <30 kg/m2, n = 209) and 'obese' (BMI >30 kg/m2, n = 245) patients.ResultsObese patients had the lowest 28-day mortality followed by overweight patients while patients with BMI <25 kg/m2 had the highest mortality (p = 0.02). Compared to the patients with BMI <25 kg/m2, obese and overweight patients also had a different pattern of infection with less lung (obese 35%, overweight 45%, BMI<25 kg/m2 50%, p = 0.003) and fungal infection (obese 8.2%, overweight 11%, and BMI<25 kg/m2 15.6%, p = 0.03). Per kilogram, obese and overweight patients received less fluid during the first four days (p<0.05) and received less norepinephrine (obese 0.14, overweight 0.21, BMI <25 kg/m2 0.26 µg/kg/min, p<0.0001) and vasopressin (obese 0.28, overweight 0.36, BMI <25 kg/m2 0.43 µU/kg/min, p<0.0001) on day 1 compared to patients with BMI <25 kg/m2. Obese and overweight patients also had a lower plasma IL-6 concentration at baseline (obese 106 [IQR 34-686], overweight 190 [IQR 44-2339], BMI <25 kg/m2 235 [IQR 44-1793] pg/mL, p = 0.046).ConclusionsOverall obesity was associated with improved survival in septic shock and differences in pattern of infection, fluids, and vasopressors. Importantly, the magnitude of inflammatory IL-6 response is muted in the obese.

Incidence of high body mass index in critically ill cancer patients

“…The group of patients with overweight and obesity are at a major risk of developing chronic diseases, such as systemic arterial hypertension and diabetes mellitus; however, in our study, less than 20% of the patients had a history of those clinical entities (15,28).…”

“…However, in the context of critically ill oncologic patients with high BMI, the impact on mortality is unknown. Different reports have described that in patients with sepsis and septic shock, obesity is a protective factor against death (14)(15)(16)(17)(18).…”

Norepinephrine Dosing in Obese and Nonobese Patients With Septic Shock

“…Recent studies [16][17][18][19] have indicated that the outcomes (ie, hospital mortality) and characteristics (ie, type of underlying infection) of critically ill obese patients differ from those of nonobese patients. These differences may be due to underlying pathophysiological mechanisms or differential use of therapies or suboptimal drug dosing.…”

Intensive Care: Who Benefits?

“…On one hand, obesity does induce a chronic low-grade inflammatory state 38 and obese critically ill patients do have lower early levels of Interleukin-6 in sepsis. 39 Furthermore there is a tendency not to fully dose obese patients on a true mg/kg or mL/kg basis; as a result such obese patients may be 'relatively undertreated' which in other Table 5 Prognosis at collapse; discharged home or to rehabilitation. 29 intensive care spheres (eg, fluids, blood transfusion, vasopressors) have enhanced survival.…”