Increased incidence of axonal Guillain‐Barré syndrome in La Spezia area of Italy: A 13‐year follow‐up study

Guillain-Barre syndrome (GBS) is an acute immune-mediated polyradiculoneuropathy with a worldwide incidence of 0.81-1.89 per 100 000 person-years. In Europe and North America only 5% of patients with GBS have axonal subtypes, which in South America and Asia account for 30%-47% of cases. The aim of our study is to assess the annual incidence and clinical features of GBS in La Spezia area in Italy. A retrospective (from 1 January 2003 to 31 December 2011) followed by a prospective (from 1 January 2012 to 31 December 2015) analysis was carried out on patients admitted to La Spezia hospital who fulfilled the GBS diagnostic criteria. A total of 86 patients (58 men), mean age of 62.7 years (range 21-90), were included. The mean annual incidence rate was 3/100 000 (range: 0.9/100 000-5.37/100 000) significantly higher than the European incidence (P < 0.001). Forty-seven percent were classified as acute inflammatory demyelinating polyradiculoneuropathy (AIDP), 35% as acute motor and motor-sensory axonal neuropathy (AMAN-AMSAN), 13% as variant forms, and 5% were not defined. AIDP was most common in "Golfo dei Poeti" (50%) and "Val di Magra" (63.2%), whereas AMAN/AMSAN prevailed in "Val di Vara" (63.6%) and "Riviera Spezzina" (62.5%) (P = 0.024). In La Spezia area GBS incidence (especially the AMAN subtype) is significantly higher than the incidence reported in Europe. AIDP predominates in the eastern area whereas AMAN/AMSAN in the western, with a significantly different incidence rate (P = 0.003). Prospective studies to assess possible predisposing environmental factors are needed.