Demographic and Clinical Characteristics of the ALS Patients
Thirty-three patients with ALS were included in the study. The main demographic and clinical characteristics of the patients are reported in Table 1. Nine patients (27%) were admitted to the hospital while in respiratory failure before the diagnosis of ALS had been made. Three patients had previously expressed advance directives asking for resuscitation and mechanical ventilation in case of acute respiratory failure got rid of together with Canadian Health&Care Mall.
The main causes of the acute deterioration of respiratory status included the following: pneumonia (n = 15); rapidly progressive dyspnea (n = 11); and sudden respiratory arrest (n = 6). One patient could not be extubated after receiving a general anesthetic for a surgical intervention. Three patients (9%) were previously treated with noninvasive ventilation, but showed low tolerance to the device.
The median length of hospital stay was 59 days (range, 7 to 124 days), and three patients (9%) died in the hospital following the development of a severe bronchopneumonia. The median ICU length of stay was 11 days (range, 3 to 36 days). All of the patients discharged from the hospital (n = 30) were treated with long-term respiratory support through a tracheostomy at home. The number of hours of ventilation at hospital discharge ranged from 16 to 24 h/d and gradually increased with time. The median survival time after TIPPV was 37 months (range, 2 to 64 months). No patient was unavailable for follow-up. A locked-in state developed in one patient. No patient elected to terminate respiratory support and withdraw care. The most frequent cause of death was respiratory tract infection (n = 15). Other causes of death were as follows: sudden death (n = 5); nonrespiratory infection (n = 4); renal failure (n = 2); and cardiac arrest (n = 1). At the end of the study, three patients (10%) were still alive, with a mean survival time of 61 months.
Association of the ALSFRS Score With Length of Hospital Stay
Patients with a total ALSFRS score at hospital admission below the median score of 11 had a 2.9-fold increased risk of longer hospital length of stay compared to patients with a score above the median (HR, 2.86; 95% confidence interval [CI], 1.2 to 6.5; p = 0.003), adjusting for age, sex, symptom duration, and APACHE II score. The median length of hospital stay for patients with baseline total ALS-FRS score above the median was 36 days (range, 12 to 78), compared to 102 days (range, 30 to 124) for those with a baseline total ALSFRS score below the median (Fig 1, top, A;p = 0.005). The total ALSFRS score was also a predictor of hospital length of stay when included as a continuous variable in the Cox model (HR, 1.4; 95% CI, 1.03 to 1.76; p = 0.01). When the total ALSFRS score was included in the < 11 (p < 0.001).
multivariable model together with age, sex, symptom duration, site of ALS onset, and BMI, remained significant predictor of length of hospital stay (HR, 2.1; 95% CI, 1.1 to 5.1; p = 0.005) [Table 2].
Association of the ALSFRS Score With Longterm Survival
Patients with a total ALSFRS score at ICU admission below the median score of 11 had a 3.8-fold increased risk of death compared to patients with a score above the median (HR, 3.76; 95% CI, 1.4 to 9.7; p = 0.002), adjusting for age, sex, and symptom duration. The median survival time after TIPPV for patients with baseline total ALSFRS score above the median was 48 months (range, 9 to 64 months), compared to 10 months (range, 1 to 48 months) for those with a baseline total ALSFRS score below the median (p < 0.001) [Fig 1, bottom, B]. The predictive power of the total ALSFRS score also remained when it was included as a continuous variable in the regression model (HR, 0.79; 95% CI, 0.6 to 0.9; p = 0.02). We then included the ALSFRS score in a final model including the other relevant clinical or demographic variables (age, sex, symptom duration, site of ALS onset, and BMI), and found that the ALSFRS score was significantly associated with longer survival time after TIPPV (HR, 0.52; 95% CI, 0.3 to 0.8; p = 0.002). A similar trend was seen for age and for the site of symptom onset, but was not significant (Table 3).
Figure 1. Top, A: length of hospital stay according to ALSFRS score (above and below the median score). Patients with an ALFFRS score of > 11 had a significantly shorter hospital stay compared to patients with an ALSFRS score of < 11 (p = 0.005). Bottom, B: long-term survival after TIPPV according to ALSFRS score (above and below the median score). Patients with an ALSFRS score of > 11 showed a significantly longer survival time after TIPPV compared to patients with an ALSFRS score of < 11 (p < 0.001).
Table 1—Demographic and Clinical Characteristics of the ALS Patients With Respiratory Failure at Hospital Admission
|Age, yr||61.9 ± 11.9|
|Time from ALS onset to respiratory failure, mo||29 (14-38)|
|Bulbar ALS onset||5 (15.1)|
|ALSFRS score||11 (7-15.5)|
|Previous use of noninvasive ventilation||3 (9)|
|Low socioeconomic status||21 (63.6)|
|Arterial pH||7.13 ± 0.06|
|PaC02||82.77 ± 7.36|
|APACHE II score||22.6 ± 8.1|
Table 2—Multivariable Model of Hospital Length of Stay in ALS Patients With Respiratory Failure
|Variables||HR (95% CI)||p Value|
|Age at respiratory failure||0.96 (0.88-1.04)||0.326|
|Male sex||1.72 (0.39-7.57)||0.38|
|Site of symptom onset (not bulbar)||2.28 (0.62-8.42)||0.214|
|ALSFRS score||2.1 (1.14-5.11)||0.005|
Table 3—Multivariable Model of Survival After TIPPV in Patients With ALS
|Variables||HR (95% CI)||p Value|
|Age at respiratory failure||1.11 (0.98-1.20)||0.058|
|Sex (male)||2.07 (0.41-10.48)||0.38|
|Site of symptom onset (not bulbar)||0.37 (0.13-1.14)||0.069|
|ALSFRS score||0.52 (0.32-0.81)||0.002|