Endocrine Abstracts

Cushing’s syndrome (CS) is a disease entity that through hypercortisolism affects all body’s tissues leading to increased morbidity, decreased quality of life and mortality. Muscles are among the tissues primarily affected. However, data on the impact of endogenous hypercortisolism on functional muscle capacity and daily physical activity levels are scarce. We studied 23 subjects with endogenous CS (mean age: 40.73±2.17 years) and 22 healthy aged and sex matched controls. Assessment of the degree of hypercortisolism was based on cortisol day-curve, midnight cortisol and 24 h urine cortisol levels (UFC). Body composition was measured by bioelectrical impedance method (BIA). Functional capacity was assessed by the 6-min walking distance test (6MWT) and by quadriceps muscle strength and endurance during maximal isometric voluntary contraction test (QMVC). Respiratory muscles strength was assessed during maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) manoeuvres. Daily physical activity in terms of number of steps (steps/day) and body movement acceleration (VMU/min) was recorded by a triaxial accelerometer (Actigraph GT3X) during 7 consecutive days. The fat mass was greater in CS patients compared to controls (P=0.005). No differences were found between the two groups in the parameters of MIP (P=0.79) and MEP (P=0.66). Muscle force and endurance were significantly compromised in patients with CS (P=0.04). Six minute walking distance covered was lower in CS group (P<0.001). In addition, 6MWT was well correlated with time lapsed since diagnosis (P=0.02). Daily physical activity levels were lower in CS group compared to controls (steps/day, P=0.0001, and VMU/min, P=0.0001). Finally, there was a strong negative correlation between daily physical activity in terms of body movement acceleration (VMU/min) and biochemical indices of hypercortisolism. In conclusion, endogenous hypercortisolism has a profound negative influence on various parameters related to functional capacity and daily physical activity and these measurements may be a useful tool.