Osteosarcopenia in acromegaly: reduced muscle quality and increased vertebral fat deposition.

PURPOSE: Musculoskeletal disorders are among the most disabling comorbidities in patients with acromegaly. This study examined muscle and bone quality in patients with acromegaly.

METHODS: Thirty-three patients with acromegaly and nineteen age- and body mass index-matched healthy controls were included in the study. Body composition was determined using dual-energy X-ray absorptiometry. The participants underwent abdominal magnetic resonance imaging (MRI) for cross-sectional evaluation of muscle area and vertebral MRI proton density fat fraction (MRI-PDFF). Muscular strength was measured using hand grip strength (HGS). Skeletal muscle quality (SMQ) was classified as weak, low, or normal, according to HGS/ASM (appendicular skeletal muscle mass) ratio.

RESULTS: Groups had similar lean tissues, total body fat ratios, and total abdominal muscle areas. Acromegalic patients had lower pelvic BMD (p = 0.012) and higher vertebral MRI-PDFF (p = 0.014), while total and spine bone mineral densities (BMD) were similar between the groups. The SMQ score rate was normal only 57.5% in the acromegaly group, and 94.7% of the controls had a normal SMQ score (p = 0.01). Subgroup analysis showed that patients with active acromegaly (AA) had higher lean tissue and lower body fat ratios than controlled acromegaly (CA) and control groups. Vertebral MRI-PDFF was higher in the CA group than that in the AA and control groups (p = 0.022 and p = 0.001, respectively). The proportion of participants with normal SMQ was lower in the AA and CA groups than that in the control group (p = 0.012 and p = 0.013, respectively).

CONCLUSION: Acromegalic patients had reduced SMQ and pelvic BMD, but greater vertebral MRI-PDFF. Although lean tissue increases in AA, this does not affect SMQ. Therefore, increased vertebral MRI-PDFF in controlled acromegalic patients may be due to ectopic adiposity.