Publication

Limitations of sniff nasal pressure as an outcome measurement in amyotrophic lateral sclerosis patients in a clinical trial

Journal Paper/Review - Jul 28, 2012

Units
PubMed
Doi

Citation
Bauer M, Czell D, Hartmann S, Goldman B, Müller D, Weber M. Limitations of sniff nasal pressure as an outcome measurement in amyotrophic lateral sclerosis patients in a clinical trial. Respiration 2012; 84:306-11.
Type
Journal Paper/Review (English)
Journal
Respiration 2012; 84
Publication Date
Jul 28, 2012
Issn Electronic
1423-0356
Pages
306-11
Brief description/objective

BACKGROUND
The forced vital capacity (FVC) is an established measure in amyotrophic lateral sclerosis (ALS) clinical trials. Recently the sniff nasal inspiratory pressure (SNIP) test has been increasingly used as a respiratory measure.

OBJECTIVES
It was the aim of this study to assess the feasibility of SNIP as an outcome measure in a phase III clinical trial with a lead-in design.

METHODS
Twenty patients were enrolled in a randomized clinical trial. FVC, SNIP in sitting (SNIPsitt) and supine (SNIPsup) positions, and the ALS functional rating scale score (ALSFRS-R) were measured every 4 weeks.

RESULTS
Complete data were available for 19 patients over 5 months. Baseline values were normal for FVC (101 ± 14%) but abnormal for SNIPsitt and SNIPsup (84 ± 34% and 82 ± 33%). While FVC and ALSFRS-R declined in parallel, SNIPsitt measures declined significantly less compared to ALSFRS-R (p < 0.05) and FVC (p < 0.001) up to 4 months after enrollment. Over 50% of patients still had values equal to or above baseline SNIPsitt measures after 3 months despite abnormal baseline values.

CONCLUSIONS
The delayed decline in SNIP measurements suggests a learning effect over time. The optimal number of SNIPs in ALS clinical trials has yet to be determined. SNIP measures should be used with caution in trials with a lead-in design.