Abstract
BACKGROUND: Muscle health decline with age, but its deterioration in older persons with type-2 diabetes mellitus (T2DM) over time is not well-established. This study aimed to determine the change in muscle mass, handgrip strength and gait speed over time among community-dwelling ambulatory older multi-ethnic Asian patients with T2DM and their associated factors. METHODS: Among 387 eligible patients aged 60-89 years who were recruited at baseline, 348 (89.9%) were reviewed at a public primary care clinic in Singapore in the subsequent 9 to 34 months. The change in their clinical and functional status, levels of physical activity and muscle status (mass, grip strength and gait speed based on the Asian Working Group for Sarcopenia criteria) were recorded and compared. Their physical activity levels were assessed using the Physical Activity Scale for the Elderly (PASE) and International Physical Activity Questionnaire (IPAQ). Their quality of life was evaluated based on the World Health Organization Quality of Life (WHOQOL) domains. Linear regression analysis was used to identify the factors associated with muscle health change. RESULTS: The study population comprised men (52.9%), Chinese (69.3%), mean age of 68.4 ± SD5.6 years and had at least secondary education (76.4%). Their mean muscle mass significantly decreased by 0.03 ± SD0.06 kg/m(2)/month, mean handgrip strength by 0.06 ± SD0.26 kg/month and negligible change in gait speed of 0.002 ± SD0.01 m/sec/month. Their mean weight significantly decreased by 0.5 ± SD3.9 kg, waist and hip circumferences by 2.5 ± SD6cm and 3.2 ± SD5.1 cm respectively, with no change in BMI. Linear regression shows significant associations between muscle mass change and education level (β = 0.36,p = 0.012, 95% CI = 0.08-0.64), BMI (β = 0.11,p = < 0.001, 95% CI = 0.05-0.17), change in medication class (β = 0.39,p = < 0.001, 95% CI = 0.06-0.71) and review interval (β = - 0.003, p < 0.001, 95% CI = -0.004--0.002). Gait speed change was associated with singlehood (β = - 0.13,p = 0.029, 95% CI = -0.25--0.01) and WHOQOL physical health (β = 0.01,p = 0.024, 95% CI = 0.00-0.02) domain. No factor was associated with handgrip strength change. CONCLUSIONS: The study population with T2DM showed significant decline in their mean weight, waist and hip circumferences, mean muscle mass and mean grip strength but gait speed was unaffected. Muscle mass change was associated with education level, BMI and length of review interval. Handgrip strength change was not significantly correlated with any factor. Gait speed change was associated with singlehood and physical health.