Original Abstract
AIM: To investigate the association of accelerometry daily step count with 3-year overall survival (OS) in patients with malignant pleural effusion (MPE). METHODS: This is a pooled analysis of four studies in patients with MPE. Activity behaviour was captured using 7-day accelerometry (Actigraph GT3X+) and survival information was collected from medical records. Participants were divided in two groups based on median number of steps: high (n=81, median of 7509 [interquartile range (IQR): 5699; 9844] steps) and low steps (n=82, 2940 [IQR: 1676; 3947] steps). Data were analysed with Cox regression analyses (hazard ratio [HR] and 95% confidence intervals [95% CI]) and Kaplan-Meier method to explore the association of daily step count with 3-year OS. RESULTS: A total of 163 MPE patients had 57 and 72 deaths recorded in the high and low steps group, respectively. An unadjusted HR of 0.50 (95% CI: 0.35-0.71) was observed for those in the high steps group. High steps group presented a median 3-year OS of 18.9 (95% CI: 13.4-24.3) months vs. 9.3 (95% CI: 6.2-12.4) months in low steps (p<0.001). An adjusted HR of 0.48 (95% CI: 0.31-0.74) was observed for patients presenting with high number of steps after controlling for age, cancer type, serum albumin, Eastern Cooperative Oncology Group performance status (0, 1, 2, and 3) and sedentary time. CONCLUSION: This exploratory study indicates accelerometry-based physical activity measurement is a meaningful prognostic marker in patients with MPE, even after controlling for established prognostic factors. Accelerometry may add value to existing prognostic models.