Development and initial validation of a new preference-based disease-specific health-related quality of life instrument for erectile function.
Health-related quality of life instruments may be generic or specific. In general, only generic instruments use preference-based scoring. We report on a novel approach to combine in one instrument the strengths of the specific approach, greater disease relevance and responsiveness, with those of preference-based scoring, generalizability through utilities.


OBJECTIVE
The primary objective was to develop a self-administered, preference-based instrument capable of measuring utilities in the disease-specific context of erectile dysfunction (ED).


METHODS
Content derivation/validation began with a literature review. Eight attributes (domains) were selected to provide clinical experts structure for focus group discussion. Four levels describing a continuum of dysfunction-function were defined for each domain. Each domain, including functional levels, was reviewed and modified until consensus was achieved regarding content. This content was then integrated into a preference based scoring instrument using two visual analogue scales (VAS) with which patients rated three 'marker' health states (representing mild, moderate and severe ED), their self-state and a previously validated external marker state. The instrument was pilot tested, and implemented in a clinical trial. Initial validation analyses have been performed.


RESULTS
A self-administered, preference-based, VAS instrument was developed for use in the ED population, and the instrument was feasible to complete, was reliable beyond the threshold of acceptability established a priori and demonstrated good validity. Evidence of these properties accumulates over time and this study begins that process with this instrument. Responsiveness is being assessed in the context of a clinical trial.
Torrance
G W
GW
McMaster University, Hamilton, ON, Canada. torrance@mcmaster.ca
Keresteci
M A
MA
Casey
R W
RW
Rosner
A J
AJ
Ryan
N
N
Breton
M C
MC
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002170:Canada; D002986:Clinical Trials as Topic; D007172:Erectile Dysfunction / Q000188:drug therapy / Q000523:psychology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000295:instrumentation* / Q000379:methods; D017060:Patient Satisfaction / Q000706:statistics & numerical data*; D010879:Piperazines / Q000627:therapeutic use; D011594:Psychometrics / Q000295:instrumentation*; D011687:Purines; D011788:Quality of Life; D018434:Sickness Impact Profile; D000068677:Sildenafil Citrate; D013450:Sulfones; D011795:Surveys and Questionnaires; D014665:Vasodilator Agents / Q000627:therapeutic use
D010879:Piperazines; D011687:Purines; D013450:Sulfones; D014665:Vasodilator Agents; D000068677:Sildenafil Citrate