Abstract
A clinically useful model to prognose onset of respiratory insufficiency in amyotrophic lateral sclerosis (ALS) would inform disease interventions, communication, and clinical trial design. We aimed to derive and validate a clinical prognostic model for respiratory insufficiency within six months of presentation to an outpatient ALS clinic.
We used multivariable logistic regression and internal cross-validation to derive a clinical prognostic model using a single-center cohort of 765 ALS patients who presented between 2006 and 2015. External validation was performed using the multicenter Pooled Resource Open-Access ALS Clinical Trials (PRO-ACT) database with 7083 ALS patients. Predictors included baseline characteristics at first outpatient visit. The primary outcome was respiratory insufficiency within six months, defined by initiation of non-invasive ventilation, forced vital capacity <50% predicted, tracheostomy, or death.
Of 765 patients in our center, 300 (39%) had respiratory insufficiency or death within six months. Six baseline characteristics (diagnosis age; delay between symptom onset and diagnosis; forced vital capacity; symptom onset site; ALS Functional Rating Scale-Revised (ALSFRS-R) total score; and ALSFRS-R dyspnea score) were used to prognose the risk of the primary outcome. The derivation cohort c-statistic was 0.86 (95% confidence interval (CI), 0.84–0.89). Internal cross validation produced a c-statistic of 0.86 (95% CI, 0.85–0.87). External validation of the model using the PROACT cohort produced a c-statistic of 0.74 (95% CI, 0.72–0.75).
We derived and externally validated a clinical prognostic rule for respiratory insufficiency in ALS. Future studies should investigate interventions on equivalent high-risk patients.
Footnotes
This manuscript has recently been accepted for publication in the European Respiratory Journal. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article.
Conflict of interest: Dr. Ackrivo has nothing to disclose.
Conflict of interest: Dr. Hansen-Flaschen has nothing to disclose.
Conflict of interest: Dr. Wileyto has nothing to disclose.
Conflict of interest: Dr. Schwab has nothing to disclose.
Conflict of interest: Dr. Elman has nothing to disclose.
Conflict of interest: Dr. Kawut has nothing to disclose.
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