Demographic data and clinical characteristics
From 327 study patients, 217 (66.4%) had extALS and 110 (33.6%) buALS. We observed a female predominance among ALS patients (189/327, 58%). The proportion of women with buALS (73/110, 66%; p < 0.005) was significantly higher than for extALS (116/217, 53%; p< 0.005). Among all 327 ALS patients, 296 (91%) had died by the time of data retrieval. In the buALS group, 106 of 110 (96%) patients had died, compared to 190 of 217 (88%) patients in the extALS group. A total of 176 new ALS diagnoses were made during the 5-year study period.
The mean age at symptom onset in the buALS group (66 years) was significantly higher compared with the extALS group (59 years; p< 0.001), however in neither group was it associated with gender. A higher age significantly associated with a shorter overall survival time (r = -0.333; p < 0.001). Mean survival was 47 months among all patients (95% CI 41.5–53.3), 55 months (95% CI 46.5–63.7) in the extALS group, and 34 months (95% CI 28.9–38.7) in the buALS group. Thus, survival in the extALS group was significantly longer (p < 0.005; Figure 1). The clinical characteristics for all study patients as well as a comparison of buALS and extALS patients appear in Table 1.