At the start of the study, a clinical history, physical examination, ECG, and chest x-ray film were done. Lung (unction tests were performed with measurement of FEV1, forced vital capacity, and vital capacity (dry spirometer) before and 20 minutes after 1.25 mg terbutaline inhaled through a 750 ml cone spacer.
The patients were seen at the clinic every month the first three months and then every second or third month during the summer period. In autumn and winter, they were again seen every month, giving a total of a minimum of seven visits. They were interviewed concerning symptoms and medical treatment. After one month and at the end of the study, the patients were asked to give an overall assessment of the treatment (definitely useful, useful, not useful, harmful, or definitely harmful).
Lung function tests were performed at the start and at the end of the study. Physical examination and chest x-ray film were done after six months and when needed.
The physiotherapist instructed the patients in the technique of diaphragmatic breathing, forced expirations, and use of PEP mask and regularly controlled how the patients performed. Initially, they were instructed twice a week, then once a week during the first month. After this period of introduction, they were seen by the physiotherapist every second or third month during the summer. At the start of the winter period, the patients were again seen once or twice a week for the first month and then every second month.
Descriptive data for the patients were compared by means of unpaired Students t-test (continuous variable) or chi-square statistics (categorial variables). Data from the clinical control visits (medical treatment, assessment) were analyzed by chi-square statistics. The individual change in lung function from the first to the last visit was compared between the groups by Students f-test, and the changes in lung function in the two groups were compared by one-way analysis of variance.
From the diary, an individual average score for symptoms was calculated and the two groups compared by using the nonparametric Mann-Whitney test.
Concerning the number of acute exacerbations and use of antibiotics, the two groups were compared by calculating an average incidence rate, ie, the total number of events divided by the total number of fulfilled diary days (the observation time). Then the expected number of events in the groups was calculated and compared with the observed number of events by means of a chi- square statistic with DF = 1.
The number of fulfilled diary cards was put in relation to the maximum possible number of diary days and analyzed in a similar manner.