The Norwegian version of the chronic obstructive pulmonary disease self-efficacy scale (CSES): a validation and reliability study.

The aim of this study was to evaluate the feasibility, internal consistency and face and construct validity of the Norwegian version of the Chronic Obstructive Pulmonary Disease Self-Efficacy Scale (CSES). The CSES was translated into Norwegian according to standard procedures for forward and backward translation, and administered to 100 patients with chronic obstructive pulmonary disease (COPD) (51% men, mean age 66.1 years, range 42-82) prior to their participation in an outpatient pulmonary rehabilitation programme. The CSES-N (translated version) consists of 34 items comprising five subscales describing negative affect, intense emotional arousal, physical exertion, weather/environment and behavioural risk factors. Each scale ranges from 1 to 5, with higher scores indicating better self-efficacy. For validation purposes, we measured lung function (FEV(1) , FEV(1) % predicted) and exercise capacity (ISWT), and administered the St. George's Respiratory Questionnaire (SGRQ) and Hospital Anxiety and Depression Scale (HADS). A pilot study confirmed that the CSES-N was clear, understandable and easy to self-administer. Cronbach's alpha was 0.98 for the total score (0.80-0.96 for subscales). Results showed small to medium negative correlations between all CSES-N scales and anxiety, depression (HADS), physical activity, psychosocial impact of disease and total health status (SGRQ) (-0.20 to -0.49). Small or negligible negative correlations between different CSES-N scales and respiratory symptoms (SGRQ) (-0.03 to -0.23) were found. Any correlations among exercise capacity, lung function and different socio-demographic variables (age, gender and education) and CSES-N were also small or negligible (0.00 to 0.23). This study shows acceptable feasibility, internal consistency and face and construct validity for the CSES-N in a sample of Norwegian COPD patients.