Background: The Manchester Respiratory Activities of Daily Living Questionnaire is a new scale designed to assess respiratory disability in elderly outpatients with chronic obstructive pulmonary disease. However, it has not been examined for its reliability as a postal questionnaire.
Objective: To investigate test-retest reliability of the Manchester Respiratory Activities of Daily Living as a postal questionnaire and to compare face-to-face administration by a physiotherapist with postal completion.
Design: Two single-blind studies were performed to investigate test-retest reliability of the Manchester Respiratory Activities of Daily Living Questionnaire in elderly patients with chronic obstructive pulmonary disease. Study 1 comprised 51 subjects (27 men) with chronic obstructive pulmonary disease, aged 61-87 (mean 74) years. They completed the Manchester Respiratory Activities of Daily Living Questionnaire twice mailed to them at home (second questionnaire after two weeks). Study 2 comprised a separate and previously unstudied group of 36 subjects with chronic obstructive pulmonary disease (24 men), aged 60-82 (mean 71) years who also completed the Manchester Respiratory Activities of Daily Living Questionnaire twice, first face-to-face by a physiotherapist and then two weeks later at home.
Results: Mean (SD) one second forced expiratory volume (FEV1) were: Study 1=0.93 (0.30) litres; Study 2=1.01 (0.43) litres. Mean [SEM] difference between two periods Manchester Respiratory Activities of Daily Living Questionnaire score (Study 1) was 0.07 [0.3] and (Study 2) was 0.17 [0.5]. The 95% limits of agreement were -0.69 to +0.54 and -1.21 to +0.87 and standard error of measurement of 'repeatability' square root 1.55 and 1.71 respectively for Manchester Respiratory Activities of Daily Living Questionnaire. Intraclass correlation coefficients were Study 1, ICC (1,1)=0.92, 95% confidence interval 0.87 to 95; Study 2, ICC (1,1)=0.86, 95% confidence interval (0.79 to 94).
Conclusion: The Manchester Respiratory Activities of Daily Living Questionnaire scale is acceptable and repeatable as a postal questionnaire in elderly patients with chronic obstructive pulmonary disease.