Handgrip strength is a comorbidity marker in systemic necrotizing vasculitides and predicts the risk of fracture and serious adverse events.

Objective: Sarcopenia has been associated with poor outcomes in various medical and surgical conditions. However, its impact in systemic necrotizing vasculitides (SNV) had never been characterized. We aimed to assess the prevalence, associated factors and prognostic impact of sarcopenia in SNV.
Methods: Patients with SNV were successively included in a prospective longitudinal study assessing comorbidities. At inclusion, we evaluated sarcopenia by assessing skeletal muscle mass index using DXA and muscle strength using handgrip strength. Vasculitis and treatments-related events were recorded and analysed using Cox models.
Results: One hundred and twenty patients were included. At inclusion, low handgrip strength (<30 kg for men and 20 kg for women) was identified in 28 (23%) patients, while no patient exhibited low skeletal muscle mass index (<7.23 kg/m2 for men and 5.67 kg/m2 for women). Low handgrip strength was associated with age (P <0.0001), type of vasculitis (P =0.01), vasculitis damage index (P =0.01), history of falls (P =0.0002), osteoporosis (P =0.04), low serum albumin (P =0.003) and prealbumin (P =0.0007), high CRP (P =0.001), high FRAX® tool (P =0.002) and low bone mineral density at femoral neck (P =0.0002). After median follow-up of 42 months, low handgrip strength was associated with higher risk of bone fracture [HR 4.25 (1.37-13.2), P =0.01] and serious adverse events [HR 2.80 (1.35-5.81), P =0.006].
Conclusion: Handgrip strength is associated in SNV with nutritional status and comorbidities such as bone disease, and seems to predict, as in other medical conditions, the risk of fracture and serious adverse events during follow-up. In contrast, assessment of skeletal muscle mass index in this population remains uncertain.
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