Abstract B017: Adverse events following immune checkpoint inhibitors by pre-existing comorbidities and polypharmacy among patients with lung cancer: A population-based study
Authors: Nikita Nikita , Sharma Swapnil , Shaver Amy , Gandhi Krupa , Keith Scott , Yang Christopher , Gordon Sarah , Lu-Yao Grace 
Published: December 2023

Introduction: Pre-existing comorbidities and polypharmacy (PP) are significant issues among older lung cancer patients leading to complex treatment decisions. Immune check inhibitors (ICIs) have significantly improved lung cancer outcomes; however, most patients with comorbidities are excluded from ICI trials. Moreover, medication management in older adults with cancer is complex due to the volume of medications used and existing comorbidities requiring a high degree of coordination among multiple specialists. This study aims to understand the impact of pre-existing comorbidities and PP among older lung cancer patients using ICI.  Methods: We used Surveillance, Epidemiology, and End Results (SEER)-Medicare-linked data to identify patients aged ≥66 diagnosed with lung cancer (1999-2017) having continuous Medicare coverage for up to 2 years or until death. Immune-related adverse events (irAEs) grade 3/4 were defined as immune-suppressive medication claims during inpatient hospitalization 2 years after ICI, excluding the 14 days before the hospitalization. Comorbidities were calculated using a modified Charlson comorbidity index (CCI) and stratified into 3 groups: 0, 1, and more than 2 conditions. PP was stratified into 3 groups: No PP (&lt;5 medications), PP (5-9 medications), and excessive PP (&gt;10 medications). Incidence rates (IRs) and adjusted IR ratios (IRRs) were determined using negative binomial regression. The IRR model was adjusted for age, race, marital status, SEER region, state buy-in, education, and income.  Results: We identified 2,461 lung cancer patients treated with ICIs. The IR for grade 3/4 irAEs was 27.59 per 100 person-years (PY) for CCI³2, 20.25 per 100 PY among 1 CCI, and 14.99 per 100 PY among no CCI. Overall IR of grade 3/4 irAEs was 29.29 per 100  PY among patients with excessive PP vs. 19.25 per 100 PY among  PP and 13.99 per 100 PY among no PP. Patients with CCI more than 2 are 1.53 times more likely to develop a grade 3/4 irAE than those without CCI (IRR: 1.53; 95% CI: 1.09-2.14). Patients with excessive PP were 1.92 times more likely to develop a grade 3/4 irAE than those using &lt;5 medications (IRR: 1.92; 95% CI: 1.31-2.83).   Conclusion: Older adults with lung cancer usually have pre-existing comorbidities and, on average, use at least 11 concurrent medications. Multi-morbidity and polypharmacy are associated with a higher rate of irAEs among these patients; therefore, it’s critical to pay close attention to this population while on ICIs. Further studies are warranted to confirm these findings.   

Citation Format: Nikita Nikita, Swapnil Sharma, Amy Shaver, Krupa Gandhi, Scott Keith, Christopher Yang, Sarah Gordon, Grace Lu-Yao. Adverse events following immune checkpoint inhibitors by pre-existing comorbidities and polypharmacy among patients with lung cancer: A population-based study [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr B017.