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RESEARCH PRODUCT

Prognostic Relevance of Cardiorespiratory Fitness as Assessed by Submaximal Exercise Testing for All-Cause Mortality: A UK Biobank Prospective Study

Setor K KunutsorSetor K KunutsorFrancesco ZaccardiPeter WilleitUrho M. KujalaUrho M. KujalaHassan KhanThomas YatesThomas YatesJari A. LaukkanenJari A. Laukkanen

subject

AdultMaleUK Biobankmedicine.medical_specialtyDatabases FactualPopulationsubmaximal testRisk AssessmentMetabolic equivalentrisk predictionInterquartile rangeCause of DeathInternal medicinemedicineHumansProspective StudiesProspective cohort studyeducationAgedBiological Specimen Bankseducation.field_of_studycardiorespiratory fitnessFramingham Risk Scorebusiness.industryHazard ratioCardiorespiratory fitnessGeneral MedicineMiddle AgedPrognosisUnited KingdomCardiorespiratory FitnessCardiovascular DiseasesExercise Testall-cause mortalityFemaleRisk assessmentbusiness

description

Objective: To investigate if the inverse associations of cardiorespiratory fitness (CRF) with all-cause and cardiovascular mortality in the general population vary among individuals who are at different pre-test risk. Patients and Methods: CRF was assessed through submaximal bike tests in 58,892 participants aged 40-69 years who completed baseline questionnaires between January 1, 2006 and December 31, 2010 in the UK Biobank study. Participants were categorized into risk categories, which determined allocation to an individualized bike protocol. These were “minimal risk (1)”, “small risk (2)” and “medium risk (3)” groups (i.e., those who cycled at 50%, 35% of predicted maximal workload and constant levels, respectively). We investigated associations of CRF with mortality across different levels of pre-test risk and determined whether CRF improves risk prediction. Results: During a median follow-up of 5.8 years, 936 deaths occurred. CRF was linearly associated with mortality risk. Comparing extreme fifths of CRF, the multivariable adjusted hazard ratios (95% confidence intervals) for mortality were 0.63 (0.52-0.77), 0.54 (0.36-0.82), 0.81 (0.46-1.43) and 0.58 (0.48-0.69) in “minimal risk (1)”, “small risk (2)” and “medium risk (3)” groups, and overall population, respectively. Addition of CRF to a 5-year mortality risk score containing established risk factors was associated with a C-index change (+0.0012; P=.49), integrated-discrimination-improvement (+0.0005; P<.001), net-reclassification-improvement (+0.0361; P=.005) and model difference (likelihood ratio test P<.001). Differences in 5-year survival were more pronounced across levels of age, smoking and sex. Conclusion: CRF, assessed by submaximal exercise testing, improves mortality risk prediction beyond conventional risk factors and its prognostic relevance varies across cardiovascular risk levels.

https://doi.org/10.1016/j.mayocp.2019.12.030