Background: Growth hormone and insulin-like growth factor 1 (IGF-1) have recently been linked to temporal muscle thickness (TMT) in acromegaly; however, the relationship between treatment response and TMT remains unclear. Objectives: To evaluate whether TMT correlates with treatment response and may serve as a surrogate marker of disease control in patients with acromegaly. Design: Retrospective longitudinal two-center study. Methods: Patients with acromegaly and non-functioning pituitary adenomas (NFPA) were included. TMT was measured on magnetic resonance imaging scans obtained before treatment initiation and after a 3-year follow-up. Baseline TMT was compared between groups. In patients with acromegaly, TMT was correlated with IGF-1 levels at diagnosis and over time, as well as with treatment response. Mixed-effects regression models adjusted for covariates were used to assess associations. Results: Imaging studies from 58 subjects were analyzed (40 with acromegaly, 18 with NFPA). Pre-treatment TMT was significantly greater in patients with acromegaly compared with NFPA (mean 10.1 mm (9.3–10.7) vs 8.1 mm (8.0–9.2), p = 0.003). Higher baseline TMT was associated with higher IGF-1 levels at diagnosis ( p < 0.01). Following treatment, mean TMT decreased from 9.6 mm at baseline to 8.8 mm at 36 months ( p = 0.001). In covariate-adjusted mixed-effects models, higher pre-treatment TMT was independently associated with increased IGF-1 levels at diagnosis and longitudinally (β = 19.59 ng/mL, p = 0.022). Conclusion: TMT correlates with biochemical disease activity and decreases after treatment, suggesting it may be a useful imaging marker of clinical activity and prognosis in acromegaly. Trial registration: Not applicable.
Navas-Moreno et al. (Sun,) studied this question.