Estimated Cardiorespiratory Fitness, Comorbidity, And Health-related Quality Of Life In Korean Older Adults With Diabetes

Abstract

PURPOSE: Health-related quality of life (HRQoL) is a multidimensional subcomponent of quality of life that can be affected by health or health-related interventions. This study examined whether or not non-exercise-based estimation of cardiorespiratory fitness (eCRF) mediates the relationship of -comorbidity with HRQoL in Korean older adults with diabetes. METHODS: Data from a subgroup (n=1371) of Korean older adults with diabetes and age of ≥60 years (55% women) who participated in the 2008-2011 Korean National Health and Nutritional Examination Survey were used in this analysis. HRQoL was assessed with the EuroQoL-5 dimensions index and EuroQoL visual analogue scale. Comorbidity was defined as physician-diagnosed chronic conditions. eCRF was assessed with a non-exercise regression equation derived from sex, age, body mass index, and self-reported physical activity. The SPSS macro provided by Preacher and Hayes was used to test whether CRF mediated the relationship between comorbidity and HRQoL at p=0.05. RESULTS: The total effect of the presence of comorbidities on HRQoL was significant (path c; β=-2.670, 95% CI=-3.868 ~ -1.472, p<0.001). The presence of comorbidities was negatively related to eCRF in HRQoL model (path a: β=-0.529, 95% CI=-0.652 ~ -0.404, p<0.001). The effect of eCRF as a mediator on HRQoL was also significant (path b: β=1.434, 95% CI=0.928 ~ 1.940, p<0.001). The mediation analysis using the bootstrapping method (5,000 resamples) showed that eCRF mediated the relationship between the presence of comorbidities and HRQoL in Korean older adults (path ab: β=-0.757, 95% CI=-1.104 ~ -0.453, Sobel test Z=-2.753, p<0.001). In addition, a direct effect of the presence of comorbidities on HRQoL was also significant (path c’: β=-1.913, 95% CI=-3.128 ~ -0.698, p<0.05). CONCLUSIONS: The current findings suggest that cardiorespiratory fitness (CRF) can contribute to explain the relationship between comorbidity and HRQoL in Korean older adults with diabetes, implying the clinical relevance that promotion of CRF may have an impact beyond physical health in the patients. This study was supported by the National Research Foundation funded by the Korean Government (NRF-2019R1I1A1A01043771).