Neck circumference as reliable predictor of mechanical ventilation support in adult inpatients with COVID-19: a multicentric prospective evaluation

Aims: COVID-19 is especially severe for elderly subjects with cardio-metabolic and respiratory comorbidities. Neck circumference (NC) has been shown to be strongly related to cardiometabolic and respiratory illnesses even after adjustment for body mass index (BMI). We performed a prospective study to investigate the potential of NC to predict the need for invasive mechanical ventilation (IMV) in adult COVID-19 inpatients. Materials and methods: we prospectively and consecutively enrolled COVID-19 adult patients admitted to dedicated medical wards of two Italian hospitals from March 25th to April seventh 2020. On admission, clinical, biochemical and anthropometric data, including BMI and NC were collected. As primary outcome measure, the maximum respiratory support received was evaluated. Follow-up time was 30 days from hospital admission. Results: we enrolled 132 subjects (55.0-75.8 years, 32% female). During the study period, 26 (19.7%) patients underwent IMV. In multivariable logistic regression analyses, after adjusting for age, sex, diabetes, hypertension and COPD, NC resulted independently and significantly associated with IMV risk (adjusted OR 1.260 - per 1 cm increase 95% CI:1.120-1.417; P < 0.001), with a stronger association in the subgroup with BMI ≤30 Kg/m2 (adjusted OR 1.526; 95% CI:1.243-1.874; P < 0.001). NC showed a good discrimination power in predicting patients requiring IMV (AUC 0.783; 95% CI:0.684-0.882; P < 0.001). In particular, NC > 40.5 cm (>37.5 for females and > 42.5 for males) showed a higher and earlier IMV risk compared to subjects with lower NC (Log-rank test:P < 0.001). Conclusions: NC is an easy to measure parameter able to predict the need for IMV in adult COVID-19 inpatients.