Prediction of peak oxygen consumption in patients with intermittent claudication

Determination of peak oxygen consumption (VO2peak) is considered important for assessing a patient's functional capacity and for exercise prescription. However, the equipment necessary to obtain accurate determination of VO2peak is not always available in clinical settings. The present study sought to develop an equation to estimate VO2peak in peripheral arterial occlusive disease (PAOD) patients with intermittent claudication and to determine independent predictors of VO2peak in this population. One hundred and fifty-seven patients with intermittent claudication were assigned to either a validation group (n = 105) or a cross-validation group (n = 52). Medical history, height, weight, body mass index (BMI), age, gender, smoking status, resting and postexercise ankle/brachial systolic pressure index (ABI), and time to maximal claudication pain and maximal heart rate from an incremental graded exercise test (GXT) were used as potential independent predictors of VO2peak. Time to onset of maximal claudication pain, maximal heart rate, and BMI were all independently associated with VO2peak. These variables were used to estimate VO2peak by the following equation: VO2peak (mL/kg/min) = (0.00872 x maximal claudication pain time [sec]) + (0.02839 x maximal heart rate [b/min]) - (0.12034 x BMI) + 10.11411 r = 0.71, r2 = 0.50, standard error of estimate = 2.02 mL/kg/min, p < 0.0001There was no significant difference between the estimated and actual VO2peak in the cross-validation group, and the coefficient of variation between estimated and actual VO2peak in this group was 18.3%. There was no significant difference between the correlation coefficient for the relationship between estimated and actual VO2peak in the cross-validation group (r = 0.61) and the multiple correlation coefficient from the validation group (r = 0.71). Results of this study suggest that a multiple regression equation can be used to estimate VO2peak in patients with intermittent claudication by measuring time to maximal claudication pain and maximal heart rate from a GXT and by measuring BMI.