Background: Rhinitis is a common worldwide problem that is still under-diagnosed and under-treated in many countries. Most epidemiological studies use only questionnaire surveys to gauge the severity of symptoms and lack objective diagnostic criteria to quantify the severity of symptoms such as nasal obstruction. The incidence of rhinitis was examined with the use of the Peak Nasal Inspiratory Flow (PNIF), the Sino-Nasal Outcome Test 22 (SNOT-22), and the visual analogue score (VAS) with the intention to determine the efficacy of PNIF as an objective diagnostic tool for rhinitis and to establish normal reference values for PNIF and SNOT-22 in a normal population.

Materials and Methods: PNIF, SNOT-22, and VAS of 256 subjects with and without rhinitis from the general population were evaluated.

Results: The incidence of rhinitis was 51% with PNIF, SNOT-22, and VAS scores being significantly better (p<0.01) in subjects without rhinitis compared to subjects with rhinitis. Median PNIF for the population with rhinitis and without was 90 L/minute and 110 L/minute, respectively. Median SNOT-22 for the population with rhinitis and without was 41 over 110 and 4 over 110, respectively. Fifty-three percent of subjects with rhinitis were unaware of the severity of their symptoms until they completed the assessments. At a PNIF cut-off point of 95 L or less per minute, there was a moderate to good diagnostic potential for rhinitis. At a SNOT-22 cut-off point of 21 or less over 110, there was an excellent diagnostic potential for rhinitis. When PNIF and SNOT-22 are used together, the diagnostic accuracy for rhinitis is 97.6%.

Conclusion: The incidence of rhinitis is high and it is an unrecognized problem. PNIF is a cheap, simple, and useful objective diagnostic tool to assess changes in nasal patency and to discriminate between patients with moderate to severe rhinitis.

Keywords: Rhinitis, Peak Nasal Inspiratory Flow, SNOT-22, Nasal obstruction, Epidemiology

DOI: doi.org/10.35755/jmedassocthai.2021.05.10472

Received 18 July 2019 | Revised 3 December 2020 | Accepted 14 December 2020