Intramuscular fatty infiltration and physical function in controlled acromegaly.

INTRODUCTION

Patients with acromegaly show musculoskeletal symptoms which may persist despite disease control. Increased i.m. fat fraction is a known cause of muscle dysfunction in several disorders.

OBJECTIVE

To assess the degree of fat fraction in thigh muscles of controlled acromegaly patients and its relationship with muscle dysfunction.

METHODS

In a cross-sectional study, we included 36 patients with controlled acromegaly and 36 matched controls. We assessed the percentage of fat fraction in each thigh muscle, using MRI 2-point Dixon sequence, and muscle performance and strength using the gait speed, timed up and go, 30-s chair stand, and hand grip strength tests. We evaluated joint symptoms using the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC).

RESULTS

Intramuscular fat fraction was greater in patients than controls (P < 0.05 for muscle compartments, rectus femoris (RF), vastus intermedius (VI), adductor magnus (AM) and semimembranosus). Patients had slower gait speed and poorer performance on the 30-s chair stand and timed up and go tests than controls (P < 0.05). The greater fat fraction in the combined anterior-posterior compartment and in each muscle was associated with worse performance on timed up and go (P < 0.05). The fat fraction in the anterior-posterior compartment predicted performance on timed up and go after adjusting for muscle area, IGF-I and WOMAC functional and pain scores (β = 0.737 P < 0.001).

CONCLUSIONS

Patients with controlled acromegaly have greater thigh i.m. fatty infiltration, which is associated with muscle dysfunction. Futures studies are needed to elucidate the mechanisms underlying this relationship.