Patients with low IGF-I after curative surgery for Cushing's syndrome have an adverse long-term outcome of hypercortisolism-induced myopathy.

Abstract

BACKGROUND:

Glucocorticoid excess leads to muscle atrophy and weakness in patients with endogenous Cushing's syndrome. Insulin-like growth factor I (IGF-I) is known to have protective effects on muscle loss. We hypothesized that individual serum IGF-I concentrations might be predictive for long-term myopathy outcome in Cushing's syndrome.

PATIENTS AND METHODS:

In a prospective longitudinal study of 31 patients with florid Cushing's syndrome, we analyzed IGF-I and IGF binding protein 3 (IGFBP 3) concentrations at the time of diagnosis and following surgical remission over a period of up to 3 years. We assessed muscle strength by grip strength measurements using a hand grip dynamometer and muscle mass by bio-impedance measurements.

FINDINGS:

Individual serum IGF-I concentrations in the postoperative phase were strongly predictive of long-term grip strength outcome (rs = 0.696, P ≤ 0.001). Also, lower IGF-I concentrations were associated with a lower muscle mass after 3 years (rs = 0.404, P = 0.033). While patients with high IGF-I s.d. scores (SDS; >1.4) showed an improvement in grip strength within the follow-up period (P = 0.009), patients with lower IGF-I SDS (≤-0.4) had a worse outcome with persisting muscle dysfunction. In contrast, preoperative IGF-I concentrations during the florid phase of Cushing's syndrome did not predict long-term muscle function outcome (rs = 0.285, P = 0.127).

CONCLUSION:

Lower individual IGF-I concentrations 6 months after curative surgery for Cushing's syndrome are associated with adverse long-term myopathy outcome and IGF-I might be essential for muscle regeneration in the early phase after correction of hypercortisolism.

• Authors: Frederick Vogel, Leah Braun, German Rubinstein, Stephanie Zopp, Sarina Benedix, Holger Schneider, Katrin Ritzel, Katharina Schilbach, Ralf Schmidmaier, Felix Beuschlein, Martin Bidlingmaier, Martin Reincke
• Journal: European journal of endocrinology (Eur J Endocrinol) Vol. 184 Issue 6 Pg. 813-821 (May 04 2021) ISSN: 1479-683X [Electronic] England
• PMID: 33830940 (Publication Type: Journal Article)

Chemical References

• IGF1 protein, human
• Insulin-Like Growth Factor I

Topics

• Adult
• Cushing Syndrome (complications, surgery)
• Female
• Hand Strength
• Humans
• Insulin-Like Growth Factor I (analysis)
• Longitudinal Studies
• Male
• Middle Aged
• Muscle Strength
• Muscular Diseases (blood, diagnosis, etiology)
• Prospective Studies
• Treatment Outcome