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Background: Cushing's syndrome (CS) is associated with skeletal muscle structural and functional impairment which may persist long‐term despite surgical removal of the source of cortisol excess. Prevalence of sarcopenia and its impact on Health‐Related‐Quality of Life (HRQoL) in 'cured' CS is not known. There is a need to identify easy biomarkers to help the clinicians recognise patients at elevated risk of suffering sustained muscle function. Patients and Methods: We studied 36 women with CS in remission, and 36 controls matched for age, body mass index, menopausal status, and level of physical activity. We analysed the skeletal muscle mass using dual‐energy X‐ray absorptiometry, muscle fat fraction using two‐point Dixon magnetic resonance imaging and muscle performance and strength using the following tests: hand grip strength, gait speed, timed up and go and 30‐s chair stand. We assessed HRQoL with the following questionnaires: SarQoL, CushingQoL, SF‐36. We calculated the sarcopenia index (SI; serum creatinine/serum cystatin C × 100). Results: Prevalence of sarcopenia, according to the European Working Group on Sarcopenia in Older People (EWGSOP), was greater in CS as compared with controls (19% vs. 3%; p <.05). Patients with sarcopenia had a lower SarQoL score than those without sarcopenia (61 ± 17 vs. 75 ± 14; p <.05), and scored worse on the items pain, easy bruising and worries on physical appearance (p <.05 for all comparisons) of the CushingQoL questionnaire. Patients with sarcopenia had poorer physical functioning on SF‐36 than those without sarcopenia (60 ± 23 vs. 85 ± 15; p <.01). SI was lower in patients with sarcopenia than those without (71 ± 3 vs. 77 ± 2; p =.032), and was associated with intramuscular fatty infiltration, worse performance on the 30‐s chair stand test, slower gait speed, and worse muscle weakness‐related HRQoL, as measured using the SarQoL questionnaire (p <.05). The optimised cut‐off value for the SI ratio to diagnose sarcopenia was 72, which yielded a sensitivity of 73% and a specificity of 90%. Conclusions: Sarcopenia is common in patients with CS in long‐term remission, and associated with impaired quality of life. The SI is a potential biomarker allowing clinicians to identify patients at high risk of muscle dysfunction. [ABSTRACT FROM AUTHOR]

Background: Late‐onset Pompe disease (LOPD) is a genetic disorder characterized by progressive degeneration of the skeletal muscles produced by a deficiency of the enzyme acid alpha‐glucosidase. Enzymatic replacement therapy with recombinant human alpha‐glucosidase seems to reduce the progression of the disease; although at the moment, it is not completely clear to what extent. Quantitative muscle magnetic resonance imaging (qMRI) is a good biomarker for the follow‐up of fat replacement in neuromuscular disorders. The aim of this study was to describe the changes observed in fat replacement in skeletal muscles using qMRI in a cohort of LOPD patients followed prospectively. Methods: A total of 36 LOPD patients were seen once every year for 4 years. qMRI, several muscle function tests, spirometry, activities of daily living scales, and quality‐of‐life scales were performed on each visit. Muscle MRI consisted of two‐point Dixon studies of the trunk and thigh muscles. Computer analysis of the images provided the percentage of muscle degenerated and replaced by fat in every muscle (known as fat fraction). Longitudinal analysis of the measures was performed using linear mixed models applying the Greenhouse–Geisser test. Results: We detected a statistically significant and continuous increase in mean thigh fat fraction both in treated (+5.8% in 3 years) and in pre‐symptomatic patients (+2.6% in 3years) (Greenhouse–Geisser p < 0.05). As an average, fat fraction increased by 1.9% per year in treated patients, compared with 0.8% in pre‐symptomatic patients. Fat fraction significantly increased in every muscle of the thighs. We observed a significant correlation between changes observed in fat fraction in qMRI and changes observed in the results of the muscle function tests performed. Moreover, we identified that muscle performance and mean thigh fat fraction at baseline visit were independent parameters influencing fat fraction progression over 4 years (analysis of covariance, p < 0.05). Conclusions: Our study identifies that skeletal muscle fat fraction continues to increase in patients with LOPD despite the treatment with enzymatic replacement therapy. These results suggest that the process of muscle degeneration is not stopped by the treatment and could impact muscle function over the years. Hereby, we show that fat fraction along with muscle function tests can be considered a good outcome measures for clinical trials in LOPD patients. [ABSTRACT FROM AUTHOR]