Effects of loneliness on emergency room usage in US cancer survivors.

538 Background: Loneliness among cancer survivors is linked to reduced quality of life and inferior survival outcomes. However, associations of loneliness with healthcare utilization remains understudied. We aimed to examine how loneliness relates to emergency room (ER) usage in a nationally representative sample. Methods: We identified 3,326 cancer survivors from the 2021-2022 Medical Expenditure Panel Survey. Loneliness was defined as a score of ≥6 on the three-item Loneliness Scale, which assessed how often individuals felt lacking companionship, left out, or isolated from others at time of survey. Each item was scored from 1 to 3 (1: never/rarely, 2: sometimes, 3: often). Survey-weighted logistic regression models (quasibinomial family) assessed the association of loneliness with frequent ER use (ER visits ≥3 during past year), stratified by age group 18-64 (younger) and ≥65 years (older), adjusting for age, race/ethnicity, education, comorbid illnesses, activity limitation, and health insurance, with interaction terms of loneliness and marriage or sex. Results: In all cancer survivors, 20% (724) had loneliness and 3% (96) had frequent ER use. Loneliness was associated with an average of 2.44-fold odds of frequent ER use in unmarried older survivors (95% CI: 1.16–5.05), while with no significant association among married older adults (OR: 0.14; 95% CI: 0.02-1.12), unmarried younger adults (OR: 2.08; 95% CI: 0.76-5.64), or married younger adults (OR: 1.43; 95% CI: 0.42-4.81). Loneliness was also associated with a 2.32-fold odds of frequent ER use in older women (95% CI: 1.03-5.21), while with no significant association in older men (OR: 0.76; 95% CI: 0.26-2.23), younger women (OR: 0.75; 95% CI: 0.12-4.76), or younger men (OR: 2.32; 95% CI: 1.00-5.42). Conclusions: Loneliness was prevalent in one-fifth of cancer survivors. In older adults, higher loneliness was associated with frequent ER utilization in unmarried adults and in women. Findings highlight the need to explore how loneliness impacts healthcare use and to enhance support for older cancer survivors to reduce loneliness and optimize healthcare outcomes. Odds ratio with 95% CI of loneliness in relation to frequent ER use (≥3 ER visits). 18-64 years ≥65 years Loneliness Yes No Yes No Married No 2.08 (0.76-5.64) ref 2.44 (1.16-5.05)* ref Yes 1.43 (0.42-4.81) 0.14 (0.02-1.12) Sex Women 0.75 (0.12-4.76) ref 2.32 (1.03-5.21)* ref Men 2.32 (1.00-5.42) 0.76 (0.26-2.23) *p<0.05.