All analyses were carried out using SAS System version 9.2 for Windows (SAS Institute Inc., Cary, NC). Results A total of 84 patients (37 male, 47 female) were included in this study. The median age in Group 1 was 59 years (range 49 – 65) and 76 years (66 – 85) in Group 2. NIV was tolerated by 23 subjects in Group 1 and 18 in Group 2. There were no statistically significant differences in any of the patient characteristics measured at baseline Inhibitors,research,lifescience,medical (see Table 1). Mean arterial pCO2 at the time of NIV initiation was 6.3 (SD=1.5) kPa in the

Group 1 NIV subgroup and 6.5 kPa (SD=1.3, p=0.7) in the Group 2 NIV subgroup. Mean arterial pO2 readings at the time of NIV initiation were 10.9 kPa (SD=2.2) and 9.7 kPa (SD=1.5, p=0.1) for the Group 1 and Group 2 NIV subgroups, respectively. The mean daily duration of NIV at the last control visit Inhibitors,research,lifescience,medical prior to the death 17 h (SD=7) in Group 1 and 14 h (SD=6) (p=0.2). Table

1 Patients characteristics Median Barasertib datasheet survival in the Group 1 NIV subgroup was 14 months (range 1 – 60) and 15 months (range 5 – 38) in the Group 1 conventional subgroup. No significant difference was found in survival between the NIV and conventional treatment groups among patients in Group 1 (Hazard Ratio=0.88, Inhibitors,research,lifescience,medical 95% CI 0.44 – 1.77, p=0.7). In Group 2, NIV users survived longer (median 22 months, range 3 – 65) than those undergoing conventional (median 8 months, range 1 – 26 months) treatment (Hazard Ratio=0.25, 95% CI 0.11 – Inhibitors,research,lifescience,medical 0.55, p <0.001). Group 2 NIV non-users

showed a 4-fold increased risk of mortality compared with NIV users. The Kaplan-Meier curves for both groups are presented in Figure 2. Figure 2 Kaplan-Meier survival curves for patients with and without non-invasive ventilation in two age groups. Curve comparisons were analyzed using the log rank test. Discussion This study’s retrospective analysis found that NIV use was associated with an improved survival rate in ALS patients older than 65 years. In an earlier study, del Aguila et al. found that mean age of 65 years at the Inhibitors,research,lifescience,medical time of diagnosis was an independent risk factor for adverse outcomes [3]. In the present study the risk of mortality among patients in Group 1 who did not receive NIV was four-fold when compared with NIV users. Surprisingly, there was no difference in survival rates among ALS patients under 65 years with or without NIV therapy. The median period from the onset Thiamine-diphosphate kinase of symptoms to diagnosis was 12 months in all four groups, indicating that there were no differences in diagnostic delay between the groups. The study’s retrospective design did not allow us to evaluate the impact of NIV on quality of life. However, 14 or more hours of NIV daily is likely to indicate compliance in both age groups. The mechanism by which NIV may modify survival outcomes has not been fully elucidated. It is suggested that the survival outcomes in ALS patients are improved if NIV is initiated before ventilatory function is severely reduced (i.e. before the vital capacity is reduced) [12].