A descriptive and prognostic study of systemic sclerosis-associated myopathies

Brigitte Ranque ¹, Francois-Jérome Authier ², Véronique Le-Guern ¹, Christian Pagnoux ¹, Alice Berezne ¹, Yannick Allanore ³, David Launay ⁴, Eric Hachulla ⁴, André Kahan ³, Jean Cabane ⁵, Romain Gherardi ², Loïc Guillevin ⁶ and Luc Mouthon ^1*

¹ Paris Descartes University, Faculty of Medicine, Department of Internal Medicine, Cochin, AP-HP, France
² Paris 12 University, Reference Center for Neuro-muscular Diseases, Henri Mondor, AP-HP, France
³ Paris Descartes University, Faculty of Medicine, Department of Rheumatology A, Cochin, AP-HP, France
⁴ Lille 2 University, Department of Internal Medicine,Regional University Claude-Huriez Hospital, France
⁵ Paris VI University, Department of Internal Medicine, Saint-Antoine Hospital, AP-HP, France
⁶ Paris Descartes University, Faculty of Medicine, Department of Internal Medicine, Cochin, APHP, France

^* To whom correspondence should be addressed. E-mail: luc.mouthon{at}cch.aphp.fr.

Accepted 15 November 2008

Abstract

Objectives: To describe clinical characteristics and muscle pathological features of patients with systemic sclerosis (SSc) and myopathy, and analyze their impact on muscle outcome.

Methods: Thirty-five patients with myopathy and available muscle biopsy were identified from the charts of four hospital centers and restrospectively investigated for clinical, biological and histological parameters associated with muscular prognosis.

Results: Twenty-six (74%) cases had diffuse SSc. Median time from SSc diagnosis was 5 years (range 0-23) at myopathy onset. Main myopathological features were mononuclear inflammation (63%), muscle atrophy (60%), necrosis (59%), regeneration (44%), fibrosis (24%) and/or microangiopathy (27%). After a median follow-up of 4.4 years (range 1-11 years), 24 patients (69%) showed complete or partial muscle remission. Among all clinical, biological and pathological features, only histological muscle inflammation was associated with good muscle prognosis in multivariate analysis (OR= 44.7 [2.8-704.7]). In particular, patients without muscle inflammation had a poor response to corticosteroids (38% of favourable response versus 90% in patients with inflammation).

Conclusion: Muscle histopathology is critical in the therapeutic management of SSc-associated myopathy, because patients without muscle inflammation are unlikely to get benefit from corticosteroid therapy.