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Background: Idiopathic inflammatory myopathies (IIMs) are rare systemic autoimmune disorders, with a pleiotropic clinical picture, specifically characterized from the inflammatory involvement of striate muscles. As long-term, chronic conditions, IIMs are often associated with comorbidities (CM), often resulting from damage accrual, able to impact on patients' outcomes. Objectives: The aim of the study was to estimate the prevalence of CM in a monocentric cohort of patients with IIMs, trying to identify those factors most associated with their development and to clarify their weight into the disease's burden. Methods: We retrospectively analysed medical records of consecutive patients diagnosed with IIM according the EULAR/ACR 2017 criteria, collecting data about demography, clinical characteristics, and quality of life (QoL). QoL was evaluated with Patients Reported Outcomes (PROs): Short-Form 36 Health Survey (SF-36), Functional Assessment of Chronic Illness Therapy Fatigue Subscale (FACIT-F), Health Assessment Questionnaire (HAQ), Hospital Anxiety and Depression Scale (HADS). Intergroups comparisons were assessed by using Chi-square, t-test and ANOVA. P values Results: A total of 179 patients with a mean age of 66.4±13.7 years and a mean disease duration of 10.0±7.4 years were enrolled; 116 (64.8%) were women. Seventy-nine patients (44.1%) had Dermatomyositis, 71 (39.7%) Polymyositis, 11 (6.2%) Clinically Amyopatic Dermatomyositis, 10 (5.6%) Inclusion Body Myositis, 6 (3.3%) Immune-Mediated Necrotizing Myopathy, 2 (1.1%) Juvenile Dermatomyositis. The aggregation of CM is reported in Figure 1 and their prevalence in Table 1. The most frequent CM were thyroid dysfunctions, hypertension, dyslipidaemia and hyperuricaemia. Twelve patients (6.7%) deceased during the follow-up. Female patients had a higher number of CM than males (p=0,008). Both patients' age and their disease duration directly correlated with CM accrual (respectively p=0,001 and p=0.05). Regarding antibody status, anti-HMGCoA positivity was associated with a greater number of CM (p=0.002). An IIM-related cardiac involvement correlated with a greater number of CM (p=0.04). No CM, nor their combinations in patients, were associated with a higher risk of death. Regarding medications, the number of CM was directly related with intravenous immunoglobulins (IVIg) (p=0.002) and indirectly with cyclosporin A (CyA) (p=0.02). Moreover, those patients who have changed more than two immunosuppressants (IS) have accumulated more CM (p=0.036). PROs' analysis showed the number of CM inversely correlated with Bodily Pain (p=0.001), Vitality (p=0.016) and Physical Functioning (p= 0.002) domains of SF-36. In the multivariate setting, only the correlation with age, female sex, pharmacological history and SF36 domains were maintained (p=0.001). Conclusion: These data showed more than a half of our cohort had accumulated 4 or more CM. Multi-morbid patients tended to be older and female and seemed to have been treated with a significantly higher number of IS. Moreover, their higher amount of CM compromised QoL, mostly in physical functioning outcomes. Interestingly, they did not seem to be at higher risk of death. Further studies are needed to better clarify these results; however, they might help rheumatologists to improve the assessment of IIM patients, trying to reduce CM aggregation, thus optimizing the disease's burden. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests: None declared.
Fattorini et al. (Sat,) studied this question.