Development and Preliminary Psychometrics of the Exercise Therapy Burden Questionnaire for Patients With Chronic Conditions.

OBJECTIVE: To develop and validate a self-reporting questionnaire assessing the burden of exercise therapy for patients with chronic conditions.

DESIGN: Measurement properties of an instrument.

SETTING: Outpatient clinics and tertiary care hospital.

PARTICIPANTS: Patients (N=201) with at least 1 chronic condition and performing exercise therapy.

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURES: The dimensional structure of the questionnaire was assessed by principal component analysis. Construct validity of the instrument was assessed by exploring convergent validity with the Treatment Burden Questionnaire (TBQ) and divergent validity with pain, self-efficacy, treatment satisfaction, and health state. Reliability was assessed with the Cronbach α coefficient, a test-retest method using the intraclass correlation coefficient (ICC), and Bland-Altman plotting.

RESULTS: A preliminary list of items was developed from semistructured interviews with 28 patients and reviewed by 2 expert physicians. Items obtained were reduced. Then a sample of 163 patients was used to measure the psychometrics of the Exercise Therapy Burden Questionnaire (ETBQ), consisting of 10 items. Principal component analysis extracted 1 dimension. The Cronbach α was .86 (.82-.89). Test-retest reliability (n=24 patients) was good with an ICC of .93 (.85-.97), and Bland-Altman analysis did not reveal a systematic trend. The ETBQ showed expected convergent validity with the TBQ (ρ=.52) and expected divergent validity with pain (ρ=.37), self-efficacy (ρ=-.34), treatment satisfaction (ρ=-.49), and perceived health state (ρ=-.28).

CONCLUSIONS: The ETBQ is the first questionnaire assessing exercise therapy burden in patients with chronic conditions. Its psychometric properties are promising.