The dynamic nature of frailty in metastatic spine disease patients

Frailty measures are critical for predicting outcomes in metastatic spine disease (MSD) patients. This study aimed to evaluate frailty measures throughout the disease process.

This retrospective analysis measured frailty in MSD patients at multiple time points using a modified Metastatic Spinal Tumor Frailty Index (MSTFI). Scores were 0: "not frail," 1: "mild", 2: "moderate, and ≥ 3: "severe." Measurements were taken at cancer diagnosis, spine metastasis (SM) diagnosis, and 4-month intervals up to 2-years. The change in frailty distribution was described at the general cohort and patient levels. Two-year survival was assessed from baseline frailty status at SM diagnosis.

This study included 465 patients with an average age of 62.3 years (± 12.7), 33.8% female. Prostate cancer was most common (20.9%), followed by renal cell carcinoma (15.3%), non-small cell lung cancer (NSCLC, 13.5%), and others. Frailty changed dynamically, most significantly early in the disease. Initially, 79.4% were not frail; this dropped to 60.1% at SM diagnosis and to 42.7% at 4 months. Patients with short-term (4 month) data showed rapid frailty progression, with 57% becoming moderately to severely frail (p = 0.01), whereas 45% with long-term (24 months) data remained non-frail (p < 0.0001). Contributing factors included anemia (32.7%), electrolyte abnormalities (16.9%), and malnutrition (11.4%). Histological classification influenced frailty. Higher frailty scores at metastatic diagnosis correlated with worse 2-year survival outcomes (p: <0.001-0.04), underscoring frailty's prognostic significance.

Frailty is dynamic, with a potential early intervention point to maintain or reverse it. Further research is needed to assess which frailty measures are most dynamic and amenable to intervention.