Lack of Association Observed Between BMI and Mortality Among C Difficile Hospitalizations

Daniel E Freedberg, MD

New findings suggest a lack of association between body mass index (BMI) and 30 day all-cause mortality or hospital-free days among a cohort of hospitalized patients with Clostridioides difficile infection (CDI).

“It is unlikely that BMI will be a useful factor to further risk-stratify patients with CDI,” wrote study author Daniel E Freedberg, MD, Columbia University Irving Medical Center.

The findings were presented at the 2022 Digestive Disease Week Annual Meeting in San Diego, California.

Although the incidence and severity of CDI has been showing to increase over the past decades, there are still unknowns regarding whether obesity in combination with established risk factors can aid in predicting outcomes among those hospitalized with CDI.

The current three-center retrospective study included this patient population at Columbia University Irving Medical Center, Brigham and Women’s Hospital, and NYU Langone from 2010 to 2018 to test these associations between obesity and mortality.

Eligible patients had either community-acquired or healthcare-associated CDI, as long as BMI was measured at the time of hospitalization. Investigators classified obesity as BMI:

• <20 (underweight)
• 20 - 25 (normal weight)
• 25 - 30 (overweight)
• 30 - 35 (class I obesity)
• 35 - 40 (class II obesity)
• 40 - 45 (class III obesity)
• >45 (extreme obesity)

Investigators used multivariate logistic regression to investigate the relationship between obesity and all-cause death within 30 days after the index CDI test, while a stratified analysis determined if the obesity-death relationship varied based on age. They noted hospital free-days were compared between each obesity category.

A total of 3,851 patients were analyzed, including 373 (9.7%) who died within 30 days following diagnosis of CDI, according to investigators. Following adjustment for other factors, data show BMI did not have an association with increased risk for death in any BMI category.

Investigators then noted it remained true following compression of BMI into fewer categories (adjusted odds ratio [aOR], 0.96; 95% CI, 0.69 to 1.34 for BMI >30 versus BMI 20 - 30 and aOR, 1.02; 95% CI, 0.53 - 1.87 for BMI >40 vs BMI 20 - 30).

They noted advanced age, low albumin, and elevated total bilirubin were factors most closely associated with death. Both low platelet count and elevated bilirubin were associated with increased risk of 30-day mortality in CDI patients.

Following stratification into three age groups, investigators observed trends towards increased mortality with obesity in the young (≤55 years old) and middle-aged (56 - 75 years) (P for trend = 0.33 and 0.14, respectively).

However, they observed decreased mortality with obesity in the old age group (P for trend = 0.37). They additionally found no significant difference in hospital-free days between BMI groups (Kruskal-Wallis P = 0.92).

“Future studies seeking to risk-stratify hospitalized patients with CDI may wish to test alternate variables to improve prognostication for hospitalized patients with CDI,” Freedberg concluded.

The study, “Obesity Is Not Associated with Adverse Outcomes Among Hospitalized Patients with Clostridium Difficile Infection," was presented at DDW 2022.