St. George’s Respiratory questionnaire (SGRQ)

The validated Hungarian version of SGRQ was delivered according to the SGRQ manual supplied by the copyright holder [33]. This version is validated for a 1-month recall period related to the patients’ recollection of their symptoms. SGRQ was used to determine health impairment in patients by providing three component scores and a total score. The Symptoms score characterizes the effect, frequency and severity of respiratory symptoms over the preceding 1 month. It is reflective of the patients’ perception of their recent respiratory problems. The Activity score quantifies disturbances in daily physical activity caused to patients, whereas the Impacts score covers a wide range of disturbances related to psycho-social function. The Total score summarizes the significance of the disease on overall health status. Scores are expressed as a percentage with 100 representing the worst possible health status and 0 indicating the best one. Differences in scores were considered clinically meaningful if they exceeded 4 percent points [34]. Every patient filled out the questionnaire (n = 154) by means of supervised self-administration. Data entry was performed by two independent raters. Each used the SGRQ calculator, and coded all positive responses as 1 and all negative responses as 0. Where data were missing, cells were left blank. Data entry guidelines were diligently followed. Inter-rater variability assessed by Spearman correlation was 0.976 (p < 0.001), 0.997 (p < 0.001), 0.998 (p < 0.001) and 0.998 (p < 0.001) for the Symptoms, Activity, Impacts and Total scores of SGRQ, respectively. The mean of scores obtained by the independent raters was used for statistical analysis.

In addition, answers to Question 4 (Over the last 4 weeks, I have had attacks of wheezing) was used to assess the level of symptom control of asthma patients. Answers to this question were dichotomized as follows. Patients were considered well-controlled if they responded with yes to the options “not at all/only with chest infections”. Dichotomized response to Question 4 was used for stratification of data to allow further analysis of the final multiple regression model.