Disease status and use of ventilatory support by ALS patients. BDNF Study Group

Abstract

Introduction: Use of mechanical ventilation (MV), administered either invasively via tracheostomy, or more commonly non-invasively (CPAP, BiPAP), appears to be increasing in ALS. No prospective databases exist that describe the behavior of physicians and patients and the criteria for instituting MV in ALS.

Methods: 387 placebo patients in a Phase III trial of r-metHuBDNF were followed for 9 months. Although the use of MV was not the primary end-point of the trial, information was gathered regarding it by cataloging respiratory adverse events and tracking health resource utilization.

Results: 35 of 387 patients utilized MV during the trial. Twenty-eight (7%) patients received BiPAP. Seven (2%) were tracheotomized without first receiving BiPAP. Forced vital capacity (FVC): BiPAP patients had a mean ( SEM) FVC% of 71.8 +/- 2.8% and ALSFRS of 27.7 +/- 1.0 at baseline; non-BiPAP patients had a mean baseline FVC% of 88.7 +/- 1.0%, and an ALSFRS of 30.3 +/- 0.3. Symptom duration at entry was similar for both groups (2.1 +/- 0.4 years vs. 2.1 +/- 0.1 years). At the time of first use of BiPAP, average FVC% was 47.5 +/- 4.0% and ALSFRS score was 22.4 +/- 1.5. The range of FVC% at start of BiPAP was 15-87. The nine-month survival was 67.9% for BiPAP patients vs. 86% for non-BiPAP patients. The use of BiPAP varied tremendously among the 38 study sites, with some not employing it at all and others using it in as many as 40% of patients.

Conclusions: Of the 9% of placebo patients who received MV, BiPAP patients were more rapidly progressing than non-BIPAP patients, and showed a greater eventual mortality rate. Patients began MV at a wide range of values of FVC%, and centers differed in their prescribing practices. Factors influencing BiPAP use are complex, and not strictly related to FVC%.