Interventional procedure overview of cryotherapy for chronic rhinitis

Outcome measures

The main outcomes include patient-reported outcomes (Total Nasal Symptom Score [TNSS], Nasal Obstruction Symptom Evaluation [NOSE], 22-item Sino-Nasal Outcomes Test [SNOT-22], Rhinoconjunctivitis Quality of Life Questionnaire [RQLQ] and Visual Analog Scale [VAS]) and clinician-completed assessment (clinical global impression of improvement [CGI-I]). The measures used are detailed in the following paragraphs.

The Reflective Total Nasal Symptom Score (rTNSS) rates 4 nasal symptoms (rhinorrhoea, nasal congestion, nasal itching, and sneezing) on a scale of 0 (no symptoms) to 3 (severe symptoms). The scores are summed to provide a total rTNSS with a range of 0 to 12. The minimum clinically important difference (MCID) for the rTNSS is -1.0 points and the threshold for response is at least 30% reduction relative to baseline. A variation of the TNSS questionnaire consists of 5 items (rhinorrhoea, nasal congestion, nasal itching, sneezing, difficulty sleeping because of nasal symptoms), with a total score of 0 to 15.

The NOSE evaluates 5 nasal symptoms: nasal congestion or stuffiness, nasal blockage or obstruction, trouble breathing through nose, trouble sleeping, unable to get enough air through nose during exercise or exertion. Each symptom is rated on a scale of 0 (no problem) to 4 (severe problem). The sum of the symptom scores is multiplied by 5 to provide a total score that ranges from 0 to 100 (mild 5 to 25, moderate 30 to 50, severe 55 to 75, and extreme 80 to 100). A NOSE response is defined as a person having at least 1 NOSE class improvement or at least 20% NOSE score reduction from baseline.

The SNOT-22 assesses sinonasal symptoms in general, consisting of 22 items scored using a 5-point Likert scale, ranging from 0 (no problem) to 5 (problem as bad as it can be). A total SNOT-22 score ranges from 0 to 110, with higher scores indicating worse symptoms. The MCID for the total SNOT-22 is -8.9 points.

The RQLQ contains 28 items, measuring impairments in 7 domains: activities, sleep, non-nose or eye symptoms, practical problems, nasal symptoms, eye symptoms, and emotions. Each item is rated on a 7-point scale, ranging from 0 (no impairment) to 6 (maximum impairment) and the overall RQLQ score is the mean of the 28 items, with higher scores reflecting lower quality of life. The MCID for the RQLQ is 0.5 points. The mini version contains 14 items, measuring impairments in 5 domains: activities, practical problems, nose symptoms, eye symptoms, and other symptoms. The MCID for the mini RQLQ is 0.4 points.

The 100-mm VAS is used to evaluate nasal symptoms of rhinorrhoea and congestion on a continuum over the previous week, with 0-mm representing no symptoms and 100-mm representing severe symptoms.

The CGI-I is a clinician-completed assessment, evaluating the clinician's impression of a patient's response to treatment based on their clinical observations. The CGI-I is a 7-point Likert scale that ranges from 1 (very much improved) to 7 (very much worse).