The Impact of Adverse Events on Health Care Resource Utilization, Costs, and Mortality Among Patients Treated with Immune Checkpoint Inhibitors

BACKGROUND: We investigated the association between adverse events (AEs) suspected to be immune‐related and health care resource utilization, costs, and mortality among patients receiving programmed cell death 1/programmed cell death ligand 1 immune checkpoint inhibitor (ICI) monotherapy for urothelial carcinoma, renal cell carcinoma, non‐small cell lung cancer, or Merkel cell carcinoma. PATIENTS AND METHODS: We conducted a retrospective cohort study using medical and pharmacy claims and enrollment information from U.S. commercial and Medicare Advantage with Part D enrollees in the Optum Research Database from March 1, 2014, through April 30, 2019. Claims were linked with mortality data from the Social Security Death Index and the National Death Index. Eligible patients had at least one ICI claim between September 1, 2014, and April 30, 2019. RESULTS: After adjusting for potential confounding variables, we found patients with AEs had more than double the risk of an inpatient stay (hazard ratio [HR], 2.2; 95% confidence interval [CI], 1.9–2.5) and an 80% higher risk of an emergency visit (HR, 1.8; 95% CI, 1.6–2.1) than patients without AEs. Adjusted 6‐month total costs were $24,301 higher among patients with an AE versus those without ($99,037 vs. $74,736; 95% CI, $18,828–29,774; p < .001). Mean ± SD AE‐related medical costs averaged $2,359 ± $7,496 per patient per month, driven by inpatient visits, which accounted for 89.9% of AE‐related costs. Adjusted risk of mortality was similar in patients with and without AEs. CONCLUSION: Patients with AEs had higher risks of hospitalizations, emergency room visits, and higher health care costs, driven by inpatient stays, than patients without AEs. The adjusted risk of mortality was similar between the two cohorts. IMPLICATIONS FOR PRACTICE: Patients taking immune checkpoint inhibitors (ICIs) who had adverse events (AEs) had significantly higher health care costs and utilization, driven by inpatient stays, compared with patients who did not. Given this high cost associated with AEs and the differences in the side effect profile of ICIs versus traditional chemotherapy, it is important for physicians to be cognizant of these differences when treating patients with ICIs. Ongoing evaluation, earlier recognition, and more effective, multidisciplinary management of AEs may improve patient outcomes and reduce the need for costly inpatient stays.