Comparison of Duke Activity Status Index with cardiopulmonary exercise testing in cancer patients

Purpose: The Duke Activity Status Index (DASI), a patient-administered questionnaire, is used to quantify functional capacity in patients undergoing cancer surgery.

Methods: This retrospective cohort study assessed whether the DASI was accurate in predicting peak oxygen consumption (pVO₂) that was objectively measured using cardiopulmonary exercise testing (CPET) in 43 consecutive patients scheduled for elective major cancer surgery at a tertiary cancer centre. The primary outcome measured the limits of agreement between DASI-predicted pVO₂ and actual measured pVO₂.

Results: The study population was elderly (median 63 years, interquartile range 18), 58% were male, with the majority having intraabdominal cancer surgery. Although the DASI scores were statistically related to the measured pVO₂ (N = 43, adjusted R² = 0.20, p = 0.002), both the bias (8 ml kg^{- 1} min^{- 1}) and 95% limits of agreement (19.5 to - 3.4 ml kg^{- 1} min^{- 1}) between the predicted and measured pVO₂ were large. Using some of the individual components, recalibrating the intercept and regression coefficient of the total DASI score did not substantially improve its ability to predict the measured pVO₂.

Conclusion: In summary, both the limits of agreement and bias between the measured and DASI-predicted pVO₂ were substantial. The DASI-predicted pVO₂ based on patient's assessment of their functional status could not be considered a reliable surrogate of measured pVO₂ during CPET for the population of patients pending major cancer surgery and cannot, therefore, be used as a triage tool for referral to CPET centres for objective risk assessment.