The impact of frailty on breast cancer outcomes: evidence from analysis of the Nationwide Inpatient Sample, 2005-2018.

The aims of the present study were to examine whether and how frailty impacts the outcomes of breast cancer. Data of women with breast cancer hospitalized during 2005 and 2018 were extracted from the US Nationwide Inpatient Sample (NIS) database. Frailty was identified using a novel algorithm, Hospital Frailty Risk Score (HFRS). Propensity-score (PS) matching was utilized to balance the baseline characteristics between frail and non-frail groups. In-hospital mortality, unfavorable discharge, prolonged length of stay (LOS), and total hospital cost were compared using univariate and multivariable logistic regression analyses. A total of 19,522 patients with metastatic (frailty n = 9,906; no frailty n = 9,716) and 135,200 with non-metastatic breast cancer (frailty n = 30,235; no frailty n = 104,965) were included. After adjustment, frailty was significantly and independently associated with higher risk for in-hospital mortality, unfavorable discharge, prolonged LOS, and greater hospital cost in both metastatic and non-metastatic diseases, in which the impacts of frailty was greater in women with non-metastatic disease. In stratified analysis, frailty had the greatest impact on in-hospital mortality among women had had non-metastatic disease and aged <50 years (aOR = 3.88; 95% CI: 1.95-7.73). In conclusion, frailty is associated with worse outcomes in women with breast cancer, and the effects are greater in non-metastatic disease and younger patients.