Research Article: Increased severity and relapse rate in adult anti-nuclear matrix protein 2 antibody positive myositis patients with distal limb weakness: a retrospective study in China
Abstract:
This study aimed to examine the clinical features and prognosis of patients with distal limb weakness in anti-nuclear matrix protein 2 antibody (anti-NXP2) positive myositis.
This retrospective study included the medical records of patients with anti-NXP2 antibody and follow-up data. Clinical features and prognosis of patients with and without distal limb weakness were compared. The differences in groups and survival analysis were analyzed using SPSS.
Of 110 enrolled adult patients with anti-NXP2 positive myositis, 53 showed distal limb weakness. The frequency of distal limb weakness in patients with anti-NXP2 positive myositis was highest when compared with other dermatomyositis (DM) patients. In the patients with anti-NXP2 positive myositis, the mean onset age of distal limb weakness group was younger, when compared with those without distal limb weakness (38.40?±?13.36 vs. 46.26?±?15.02?years, p =?0.005). They exhibited higher disease activity and experienced higher frequencies of severe muscle weakness, subcutaneous edema, dysphagia, and abnormal ECG (all p <?0.05). In terms of treatment, 32.1% patients with distal limb weakness received glucocorticoid (GC) pulse, which was higher than those without distal limb weakness (7.0%, p =?0.001). There were 32 patients reporting relapse. The mean dose of GC (prednisone equivalent) at relapse was higher. Nine patients with distal limb weakness died during follow-up, with infection representing the leading cause of death. The survival rate was not different in patients with and without distal limb weakness.
Adult patients with anti-NXP2 positive myositis and distal limb weakness were younger at disease onset and exhibited increased disease activity, including a higher prevalence of multi-system involvement, as well as a higher incidence of relapse during follow-up.
Introduction:
Proximal limb weakness is a hallmark feature of dermatomyositis (DM), and has been incorporated in both 2017 EULAR/ACR classification criteria for idiopathic inflammatory myopathies (IIMs) and 2018 European Neuromuscular Centre (ENMC) proposed criteria for DM ( 1 , 2 ). However, some patients with anti-nuclear matrix protein 2 antibody (anti-NXP2) positive myositis exhibit diffuse muscle involvement, leading to clinically evident distal limb weakness ( 3 ). Moreover, a previous study observed that micro-infarction…
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