MoTrPAC Cpet Core Lab - Quality Control And Threshold Determinations

The Molecular Transducers of Physical Activity Consortium (MoTrPAC) protocol includes collection of cardiopulmonary exercise testing (CPET) data as a key clinical outcome. PURPOSE: Due to the large volume of data and institutions involved in MoTrPAC, a CPET Core Lab was created to manage a CPET data repository, evaluate data quality, and analyze metabolic events in the continuous data like ventilatory thresholds (VT). METHODS: All clinical centers involved in MoTrPAC conducted CPETs on cycle ergometers following individualized ramp protocols. The CPET Core Lab determines the VTs in all past and current CPETS: VT1 (ventilatory threshold 1) and VT2 (ventilatory threshold 2 or Respiratory Compensation Point) as data permits. VT1 is the point where VE and VCO2 increase at a greater rate than VO2. VT2 occurs when VE increases curvilinearly to compensate for excess CO2 production. Two independent adjudicators review each test and independently determine VT1 and VT2. To ensure quality control between adjudicators, repeated VT readings were performed 2 times on 20 blinded tests by 3 adjudicators. This quality control (QC) evaluation process was performed to establish between- and within-adjudicator concordance and agreement by concordance coefficient correlation (ρc) and Bland and Altman analysis, respectively. Adjudicators analyzed all CPETs without doing any additional confirmatory QC. RESULTS: The metrics calculated on these data showed a high within-adjudicator concordance (ρc range 0.965 to 0.744) and agreement without significant proportional or systematic bias. Within-adjudicator coefficient of variation was below 8% (range 4.12% to 7.88%) for all adjudicators for both VT1 and VT2. The overall coefficient of variation for all adjudicators was 9.9% for VT1 and 10.7% for VT2 between adjudicators, and below 150 ml/min empirically suggested. CONCLUSIONS: VT1 and VT2 readings between-adjudicators had a good concordance and agreement. Additional QC procedures between adjudicators are planned to achieve higher levels of reliability and agreement. Supported by: MoTrPAC is supported by the NIH Common Fund