Amyotrophic lateral sclerosis: gender differences in the use of mechanical ventilation

Background and purpose: Invasive and non-invasive mechanical ventilation are therapeutic options in patients with amyotrophic lateral sclerosis (ALS). Related to known national ALS incidence figures, the study aims to examine gender aspects versus physiological data in patients with ALS commencing mechanical ventilation. Methods: Data from two nationwide registers involving all patients with ALS in Norway and Sweden who started invasive and non-invasive mechanical ventilation during 2002-2007. Results: The total ALS population on invasive and non-invasive mechanical ventilation comprised n = 308 subjects [Norway n = 96 (72% men), Sweden n = 212 (69% men)]. Compared to Swedish ALS incidence figures, our finding of a male/female ratio of 2.3/1 in patients with ALS on invasive and non-invasive mechanical ventilation shows a statistically significant male predominance in the use of mechanical ventilation (P-value 0.0084 Chi square). Only 6.7% of men and 3.8% of women had invasive (via tracheotomy) ventilation (P = 0.344). Initiation of mechanical ventilation was acute (not planned) in 18% of patients (no gender difference). Age distribution (mean age 62), pulmonary function tests (FVC%pred, FEV1%pred), daytime blood gas analyses (PaO2, PaCO2) and survival revealed no statistically significant gender differences. Conclusion: In Norwegian and Swedish patients with ALS on invasive and non-invasive mechanical ventilation, two-thirds were men. Associated with known national ALS male/female incidence figures, our finding shows that statistically significantly more men than women with ALS are using mechanical ventilation. Physiological data and survival were equal in both genders. This may indicate the need for a more aggressive approach to stimulate mechanical ventilation in female patients with ALS.