Reducing Systematic Overestimation Bias in the Duke Activity Status Index Estimated Peak Oxygen Uptake: A Cross-Sectional Analysis Using Submaximal Cardiopulmonary Exercise Testing

The Duke Activity Status Index (DASI) overestimates peak VO2 compared to cardiopulmonary exercise testing (CPET). This study examined anthropometric/demographical differences in 226 participants >60 years old undergoing submaximal CPET (smCPET). Both sexes overestimated DASI versus smCPET-derived peak oxygen uptake (VO2; males: 5.9 ± 7.7 mL kg-1 min-1; females: 7.2 ± 7.1, P < .001), with no bias differences (P = .224). Body mass index (BMI) was a primary predictor (β = .295, P = .001), showing progressive overestimation: normal/underweight (4.9 ± 7.5 mL kg-1 min-1), overweight (4.3 ± 8.5), obese I (6.4 ± 6.5), obese II+ (9.2 ± 6). A correction factor was developed: VO2 corrected = 34.08 + 0.153 × DASIsum-0.382 × BMI-0.123 × age + 1.962 × (1 for males, 0 for females).