title: Sniff nasal inspiratory pressure as a prognostic factor of tracheostomy or death in amyotrophic lateral sclerosis.
abstract: Forced vital capacity (FVC) shows limitations in detecting respiratory failure in the early phase of amyotrophic lateral sclerosis (ALS). In fact, mild-to-moderate respiratory muscle weakness may be present even when FVC is normal, and ALS patients with bulbar involvement might not be able to perform correctly the spirometry test. Sniff nasal inspiratory pressure (SNIP) is correlated with transdiaphragmatic strength. We evaluated SNIP at baseline as a prognostic factor of tracheostomy or death in patients with ALS. In a multidisciplinary tertiary care center for motorneuron disease, we enrolled 100 patients with ALS diagnosed with El Escorial criteria in the period between January 2006 and December 2010. Main outcome measures were tracheostomy or death. RECursive Partitioning and AMalgamation (RECPAM) analysis was also used to identify subgroups at different risks for the tracheostomy or death. Twenty-nine patients with ALS reached the outcome (12 died and 17 had tracheostomy). Using a multivariate model SNIP correctly classified the risk of the composite event within 1 year of follow-up with a continuous Net Reclassification Improvement cNRI of 0.58 (p = 0.03). Sex, Amyotrophic Lateral Sclerosis Functional Rating Scale revisited, site of onset, and FVC did not improve the classification of prognostic classes. SNIP ≤18 cmH2O identified the RECPAM class with the highest risk (Class 1, hazard ratio = 9.85, 95 % confidence interval: 2.67-36.29, p < 0.001). SNIP measured at baseline identified patients with ALS with initial respiratory failure. Finally, using only ALS patients with spinal onset of the disease, our findings were mostly overlapping with those reported in the models including the whole sample. At baseline, SNIP appeared to be the best predictor of death or tracheostomy within 1 year of follow-up. The measurement of SNIP in the early phase of the disease may contribute to identify patients with high risk of mortality or intubation. SNIP may also provide an additional tool for baseline stratification of patients with ALS in clinical trials.
authors.affiliation: Neuroscience and Sense Organs, Department of Basic Medical Science, Neurodegenerative Diseases Unit, University of Bari "Aldo Moro", Bari, Italy.
authors.forename: Rosa
authors.initials: R
authors.lastname: Capozzo
authors.forename: Vitaliano N
authors.initials: VN
authors.lastname: Quaranta
authors.forename: Fabio
authors.initials: F
authors.lastname: Pellegrini
authors.forename: Andrea
authors.initials: A
authors.lastname: Fontana
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Copetti
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Carratù
authors.forename: Francesco
authors.initials: F
authors.lastname: Panza
authors.forename: Anna
authors.initials: A
authors.lastname: Cassano
authors.forename: Vito A
authors.initials: VA
authors.lastname: Falcone
authors.forename: Rosanna
authors.initials: R
authors.lastname: Tortelli
authors.forename: Rosa
authors.initials: R
authors.lastname: Cortese
authors.forename: Isabella L
authors.initials: IL
authors.lastname: Simone
authors.forename: Onofrio
authors.initials: O
authors.lastname: Resta
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Logroscino
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000690:Amyotrophic Lateral Sclerosis / Q000401:mortality / Q000503:physiopathology / Q000601:surgery; D019540:Area Under Curve; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012119:Respiration; D012131:Respiratory Insufficiency / Q000503:physiopathology*; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D016019:Survival Analysis; D014139:Tracheostomy / Q000379:methods*; D014797:Vital Capacity / Q000502:physiology*