A simplified (modified) Duke Activity Status Index (M-DASI) to characterise functional capacity: a secondary analysis of the Measurement of Exercise Tolerance before Surgery (METS) study

Abstract

Background: Accurate assessment of functional capacity, a predictor of postoperative morbidity and mortality, is essential to improving surgical planning and outcomes. We assessed if all 12 items of the Duke Activity Status Index (DASI) were equally important in reflecting exercise capacity. Methods: In this secondary cross-sectional analysis of the international, multicentre Measurement of Exercise Tolerance before Surgery (METS) study, we assessed cardiopulmonary exercise testing and DASI data from 1455 participants. Multivariable regression analyses were used to revise the DASI model in predicting an anaerobic threshold (AT) >11 ml kg À1 min À1 and peak oxygen consumption (VO 2 peak) >16 ml kg À1 min À1 , cut-points that represent a reduced risk of postoperative complications. Results: Five questions were identified to have dominance in predicting AT>11 ml kg À1 min À1 and VO 2 peak>16 ml.kg À1 min À1 . These items were included in the M-DASI-5Q and retained utility in predicting AT>11 ml.kg À1 .min À1 (area under the receiver-operating-characteristic [AUROC]-AT: M-DASI-5Q¼0.67 vs original 12-question DASI¼0.66) and VO 2 peak (AUROC-VO2 peak: M-DASI-5Q 0.73 vs original 12-question DASI 0.71). Conversely, in a sensitivity analysis we removed one potentially sensitive question related to the ability to have sexual relations, and the ability of the remaining four questions (M-DASI-4Q) to predict an adequate functional threshold remained no worse than the original 12-question DASI model. Adding a dynamic component to the M-DASI-4Q by assessing the chronotropic response to exercise improved its ability to discriminate between those with VO 2 peak>16 ml.kg À1 .min À1 and VO 2 peak<16 ml.kg À1 .min À1 . Conclusions: The M-DASI provides a simple screening tool for further preoperative evaluation, including with cardiopulmonary exercise testing, to guide perioperative management.

Occam's razor at the sharp end: simplified preoperative risk assessment

“…Clinical outcomes are not systematically reported by Riedel and colleagues, 4 apart from a statement that only a recalibrated of the long form DASI and the M-DASI-4Q HR response were significantly predictive of 1-year mortality. By implication, the suite of simplified DASI indices were generally not successful predictors of the various clinical endpoints explored in this study.…”

“…In attempting to estimate functional capacity, the original DASI and the modified versions produced by Riedel and colleagues 4 are essentially predicting a predictor. Clinical outcomes are likely to be of more interest to clinicians and patients than isolated measurements of their functional capacity.…”

“…So the work of Riedel and colleagues 4 published in this issue of the British Journal of Anaesthesia to produce a suite of simplified, modified versions of the DASI is intriguing. Using elegant regression analyses on data from 1455 participants in the METS study, Riedel and colleagues 4 sought to determine which domains of the long form DASI best discriminate individuals with an oxygen consumption at anaerobic threshold (AT) >11 ml kg À1 min À1 and at peak (VO 2 peak) of >16 ml kg À1 min À1 , which are established thresholds associated with better postoperative outcomes. 5 The M-DASI-5Q is a derived form of the DASI reduced to just five simple questions, each of which has an equal weighting:…”

Modifiers of Health-Related Quality of Life by Biological, Psychological and Social Factors

“…This tool was designed to analyse and assess functional capacity in cardiovascular patients based on the patient's ability to perform activities of daily living (ADLs). A version adapted to gravely hospitalised patients was also developed, based on the SUPPORT [29] study, and more recently its use was recommended as a predictor of postoperative morbidity and mortality by assessing tolerance to exercise and thus improving the planning and outcome of surgery [64]. The original questionnaire consisted of 12 items which collect information on the possibilities of performing activities of daily living (ADLs) such as personal care, mobility, household tasks and sexual functioning in the last two weeks; the reduced version does not include sexual functioning.…”

Cardiopulmonary Exercise Testing and Other Tests of Functional Capacity

“…There is modest correlation between the DASI score and peak VO2, and DASI has a moderate ability to predict a peak VO2 > 15 mL/kg/min (AUC 0.77) [ 47 ]. A simplified modified version of the DASI (m-DASI) questionnaire using four or five questions may have similar ability to identify patients with at least moderate functional capacity [ 48 ]. A score of three using the four-question m-DASI questionnaire is associated with a 59% probability of achieving an AT > 11 mL/kg/min and a 71% probability of achieving an VO2 peak > 16 mL/kg/min [ 49 ].…”