The Respiratory Symptoms Questionnaire (RSQ), a simple 4-item tool designed to assess symptoms and severity of respiratory symptoms independent of diagnosis, is a valid and useful tool for monitoring patients with chronic obstructive pulmonary disease (COPD), asthma, or both COPD and asthma, according to study results published in European Respiratory Society Open Research.
The goal of this study was to validate the RSQ, a brief, patient reported survey that can be used for both asthma and COPD in both primary and specialist care settings. Researchers included 4 questions pertaining to the patients’ previous 4 weeks: 1) frequency of symptoms of daytime shortness of breath, wheezing, coughing and/or chest tightness; 2) frequency of rescue inhaler use in response to these symptoms; 3) degree of activity limitations as a result of symptoms; and 4) frequency of nighttime awakenings due to these symptoms.
To validate the RSQ, the researchers collected data from a larger novel observational longitudinal study, NOVELTY (ClinicalTrials.gov Identifier: NCT02760329). NOVELTY is a global, prospective study of approximately 12,000 patients from multiple countries with a physician-assigned diagnosis of asthma, COPD, or asthma and COPD. Patients in this study completed several patient-reported outcome (PRO) tools including St. George’s Respiratory Questionnaire (SGRQ), the modified Medical Research Council (mMRC) and the Asthma Control Test (ACT). Physicians were not aware of the responses to any of the PROs when they assessed severity. Data were randomly sampled from those with a physician assigned diagnosis of asthma, both asthma and COPD, and COPD alone. There were 510 patients selected from each group for a total sample size of 1530.
Patients with asthma were younger than those with both asthma and COPD and COPD alone (mean age, 52.7 vs 65.6 and 67.3 years, respectively) and more were women (64.1% vs 45.1% and 38.4%, respectively.) Patients with asthma had lower mean SGRQ scores compared with those with asthma and COPD or COPD alone. Patients with asthma also had a higher mean postbronchodilator forced expiratory volume in 1 second (FEV1) percent predicted than in those with asthma and COPD or COPD. The mean RSQ score was 5.6±4.3 out of a maximum of 16. Lower RSQ scores were found in patients in asthma alone compared with COPD alone or asthma/COPD (4.4±3.8 vs 6.0±4.3 and 6.4±4.4, respectively)
The internal consistency and scale measurement structure of the RSQ were consistent among patients with physician-assigned diagnosis of both asthma, asthma and COPD, and COPD alone. Results of the RSQ correlated with previous tools including the SGRQ which is a measure of general health in patients with both asthma and COPD, and with the ACT which is specifically for patients with asthma. However, a weaker correlation was found between the RSQ and mMRC dyspnea scale as well as between the RSQ and the EuroQoL Visual Analogue Scale (EQ VAS).
Mean RSQ scores correlated with physician-assigned diagnoses of asthma, asthma and COPD, and just COPD, and statistically differentiated those with severe disease from those with mild to moderate disease. However, there was no statistical difference in RSQ scores found between those with mild and moderate disease.
One study limitation is the lack of standardization in physician assessments of disease severity. While an overall linear relationship was shown between RSQ score and severity, approximately 10% of patients with RSQ scores of 0 were classified as severe by physicians. This suggests that factors other than respiratory symptoms may be part of the physician assessment. Another limitation is that the RSQ was based on clinical guidelines for assessing symptoms, and as such patient input into development of the RSQ was limited.
Overall, results of this study demonstrate that the RSQ is a valid, brief, and easily administered patient questionnaire that can be used to assess respiratory symptoms in patients with obstructive lung disease, regardless of diagnosis.
Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.
Karlsson N, Atkinson MJ, Mullerova H, et al; for the NOVELTY study investigators. Validation of a diagnosis-agnostic symptom questionnaire for asthma and/or COPD. ERJ Open Res. 2021;7(1):00828-2020. doi:10.1183/23120541.00828-2020