Validity and reliability of a questionnaire to measure the impact of lower urinary tract symptoms on quality of life: the Leicester Impact Scale

Abstract

Aims: To develop a condition specific quality of life measure for males and females with urinary storage symptoms of urgency, frequency, nocturia and incontinence.

Materials and methods: A sample of community dwelling males and females aged 40 years or more who were taking part in an epidemiological study provided data for development and validation of the scale. Questions were developed from literature review and discussions with clinicians and patients. Inclusion of items was dependent on levels of missing data and principal components analysis. Validity was assessed by comparison with the Hospital Anxiety and Depression Scale, the Bradburn Negative Affect Scale and single questions concerning the problematic nature of symptoms. Construct validity was assessed by comparing cases and non-cases, and patients with different symptom patterns. Test-retest and inter-rater reliability statistics were calculated for individual items. Responsiveness to change was measured in subjects taking part in a randomised controlled trial of a nursing intervention.

Results: The scale showed high levels of internal consistency and measures of construct validity were as hypothesised. Test-retest and inter-rater reliability was moderate to excellent. The distribution of scores was skewed with low levels of impact but the questionnaire was responsive to conservative treatments in patients receiving a nursing intervention.

Conclusions: The questionnaire proved to be a valid and reliable interviewer administered instrument for measuring impact of urinary symptoms.