Protocol choice influences cardiopulmonary outcomes in type 2 diabetes patients

Abstract

This study compared VO2 peak and cardiopulmonary parameters during the Bruce Protocol (BP) and a cardiopulmonary exercise test (CPX) in 8 diabetic (DG, 55.4 ± 7.0 yrs) and 13 non-diabetic (NDG, 51.5 ± 5.8 yrs) subjects. The BP VO2 peak and cardiopulmonary parameters were determined using predictive equations while the CPX VO2 peak was determined by gas analyzer. VO2 peak was significantly higher in the BP vs. the CPX for both groups. There was a significant difference in VO2 peak between groups for CPX (DG: 24.1 ± 6.4 mL·kg-1·min-1) and NDG: 32.4 ± 5.4 mL·kg-1·min-1, but not for BP (DG, 33.6 ± 8.9 mL·kg-1·min-1 and (NDG, 39.7 ± 4.5 mL·kg-1·min-1). The differences between CPX and BP corresponded to 22% for NDG and 39% for DG. Correlation between protocols was r = 0.77 for NDG and r = 0.24 for DG. Considering VO2 peak on BP, 90.5% cases changed American Heart Association (AHA) classification. Cardiopulmonary parameters were significantly different between tests. CPX was efficient in identifying differences in VO2 peak values in diabetic and non-diabetic subjects. The BP may overestimate VO2 peak values and AHA classification in DG.