Comparison of objective and subjective measurements of cough frequency in patients with seasonal allergic rhinitis.
BACKGROUND
Cough is a frequent complaint of patients with a variety of respiratory disorders, including seasonal allergic rhinitis (SAR), and it is often evaluated subjectively to determine disease status and response to treatment. However, it is not known whether subjective reports of cough from patients with SAR are accurate.


OBJECTIVE
To compare a novel objective measurement with subjective reports of cough frequency in a subset of 28 patients (aged > or = 12 years) with active SAR who were enrolled in a large, multicenter trial examining the efficacy of an active treatment for SAR.


METHODS
In this supplemental pilot study, subjective data were collected on a diary card and objective data were collected using home-based telemetry. Three 24-hour recording sessions were conducted with each patient: 2 consecutive baseline sessions (day 1 and day 2) and 1 session after randomization to placebo or active cough treatment (day 3).


RESULTS
Strong correlations existed between cough frequency data for days 1 and 2 (Spearman correlation coefficient = 0.91; P < .001) and between subjective and objective data for days 1, 2, and 3 (daytime greater than nighttime) (Spearman correlation coefficient = 0.51; P < .001).


CONCLUSIONS
These results have implications for the design and interpretation of results from clinical trials that evaluate cough frequency as a treatment outcome.
Department of Pediatrics, Allegheny General Hospital, Pittsburgh, Pennsylvania 15212, USA.
Jason
J
Krahnke
Deborah
D
Gentile
Betty
B
Angelini
Melvin
M
Danzig
David
D
Skoner
D000293:Adolescent; D000328:Adult; D003371:Cough / Q000453:epidemiology* / Q000209:etiology / Q000523:psychology; D003469:Culture; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008499:Medical Records; D018670:Monitoring, Ambulatory; D010361:Patients / Q000523:psychology; D015203:Reproducibility of Results; D006255:Rhinitis, Allergic, Seasonal / Q000150:complications*; D012720:Severity of Illness Index; D013686:Telemetry; D013997:Time Factors