Estimation Of A Preference-Based Index From The King’s Health Questionaire (Incontinence)
Incontinence is defined as an involuntary loss of urine that's enough to cause a social or hygiene concern. It is about four times more common in women than in men. By the age of 75, at least 16% of women experience some incontinence, but younger women can also be affected. Generic preference-based measures of health may not adequately cover the impact of some conditions such as incontinence. There is therefore increasing interest in developing condition specific preference-based measures.
The purpose of this study was to estimate a preference-based measure from a condition specific measure of health for urinary incontinence, the Kings Health Questionnaire, for use in economic evaluation. The King´s Health Questionnaire (KHQ) was revised into a health state classification amenable to valuation using items selected using psychometric evidence. 48 states were valued using standard gamble by a representative sample of patients with urinary incontinence attending a large UK teaching hospital outpatient clinic. Each respondent was asked to value 9 health states. Models have been estimated for predicting health state valuations for all 1024 states defined by the KHQ classification. The modelling had to cope with the clustering of data by respondent and its skewed distribution.
110 usable interviews were obtained from 169 patients approached to participate in the study. These responders generated 959 health state valuations. Mean health state values ranged from 0.77 to 0.98. Models were estimated using mean health state values and random effects models of individual level health state values. These models generated robust estimates of the `main effects´ and, in general, the results support the ordinality of the KHQ health state classification.
Brazier JE, Czoski-Murray C, Roberts J, Brown M, Symonds T, Kelleher C. Estimation of a preference-based index from a condition-specific measure: The King's health questionnaire. Medical Decision Making 2008;28(1):113-26.
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