1845P - The impact of body mass index (BMI) on immune-related adverse events (irAEs) and acute care use among patients receiving immune checkpoint inhibitors (ICIs): A population-based study

Background

ICIs are used in many solid tumors and is better tolerated than chemotherapy. However, irAEs are a concerning toxicity. Studies suggest that BMI may influence irAEs rates. We conducted a population-level study to evaluate BMI on irAEs and acute care use in patients receiving ICIs.

Methods

We used administrative data deterministically linked across databases to identify a cohort of solid tumors patients initiating ICI therapy in Ontario, Canada from June 2012-October 2018. We collected information on socio-demographics including BMI at start of ICI, clinical covariates and outcomes including acute care use and irAEs within 120 days of the last ICI dose. Multivariable Fine Gray competing risk analyses evaluated the impact of BMI on irAEs and acute care use, treating death as a competing event.

Results

Among 4683 patients, median age was 67, 57% were male; 46% had lung cancer, 35% melanoma, 9% renal; Median BMI was 26.1 (3% low, 29% normal, 27% overweight, 19% obese). Overall, 57% had an acute care episode while 7% of patients had an irAE requiring hospitalization. Increased BMI was associated with increased rate of irAEs (aHR=1.03 per 1 unit increase, 95% CI [1.01-1.04] p<0.001). Compared to patients with normal BMI, obese (aHR=1.60 [1.21-2.11] p<0.001) patients had a higher rate of irAEs. Subgroup analysis by gender found that females with increasing BMI (aHR=1.03 per unit increase [1.00-1.06] p=0.02) and obesity (aHR=2.01 [1.30-3.09] p=0.002) had higher rates of irAEs. Disease site analyses found that in patients with melanoma, obesity when compared to normal BMI (aHR=1.67 [1.10-2.53] p=0.02) was associated with increase in irAEs. In particular, in females with melanoma, obesity compared to normal BMI was strongly associated with increased irAEs (aHR=2.60 [1.36-4.96] p<0.004). BMI was not associated with overall general acute care use as a continuous or categorical variable (p>0.05).

Conclusions

Increasing BMI and obesity is associated with increasing risk for irAEs but not acute care use. The association was strongest for female patients and those with melanoma. Further research is needed to understand the mechanism of action behind this association.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

L. Eng.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.