Validation of the total illness burden index for prostate cancer (TIBI-CaP) in men with castration-resistant prostate cancer (CRPC): Data from TRUMPET.

Abstract

256 Background: The TRUMPET registry is a prospective, observational cohort study of patients (pts) with CRPC designed to evaluate treatment patterns and health-related quality of life (HRQoL) outcomes associated with CRPC and its management in a real-world setting. Comorbidities may influence how physicians approach CRPC treatment; therefore, evaluation of comorbidity presence and severity is important. The TIBI-CaP questionnaire measures comorbidity, with the aim of this analysis to validate TIBI-CaP in CRPC. Methods: Data were collected from 302 enrolled CRPC pts treated in academic and community-based sites under routine care. Baseline data collected included clinical history and self-reported demographics, comorbidities, and HRQoL. TIBI-CaP scores were analyzed based on correlation analysis and analysis of variance (ANOVA). Estimated correlations were used to verify the association of TIBI-CaP scores to scores on the SF-12v2 and FACT-P questionnaires. ANOVA models were run with SF-12v2 and FACT-P as response and quartile ranges for TIBI-CaP scores as predictor. Results: Mean age was 73.7 years. 84.7% were white; 13.9% were black. 87.8% had M1 CRPC at study entry. Mean (SD) TIBI-CaP score was 5.3 (2.72) [range 0-13], with 42.4% of CRPC pts presenting with moderate/severe comorbidity burden (higher scores). TIBI-CaP scores had statistically significant (p value < 0.0002) negative correlations with all SF-12v2 composite and domain scores. Correlation estimates for physical condition and mental condition scores were -0.46 and -0.23, respectively. TIBI-CaP scores also had statistically significant (p value < 0.02) negative correlations with FACT-P total scores and all subscales. FACT-P total scores had a -0.44 correlation estimate. F-tests showed significant differences across the four quartiles of TIBI-CaP scores and SF-12v2 and FACT-P (all p values < 0.05). Conclusions: At baseline, TIBI-CaP scores were negatively correlated with CRPC pts baseline functional status as measured by the SF-12v2 and FACT-P questionnaires. TIBI-CaP was strongly associated with HRQoL physical subscales. This analysis demonstrates validity of TIBI-CaP in CRPC pts.