The valuation of the International Prostate Symptom Score (IPSS) for use in economic evaluations.
OBJECTIVE
Lower Urinary Tract Symptoms (LUTS) suggestive of Benign Prostatic Obstruction (BPO) cause a reduction in quality of life, but the magnitude of that reduction cannot be estimated empirically. This is because survey instruments currently available merely sum the symptoms found, but do not value their impact on quality of life. It is therefore difficult to determine whether the effects of treatments for LUTS suggestive of BPO justify the costs. This complicates economic evaluations.


METHODS
We valued the impact on quality of life of patients with LUTS suggestive of BPO, by valuing health states defined by the International Prostate Symptom Score (IPSS) using the time trade-off (TTO). TTO values ranged from 1.0 for perfect health to 0.0 for the value of death, and can be used to calculate Quality-Adjusted Life Years (QALYs), the preferred outcome measure in health economics.


RESULTS
We reduced the number of health states defined by the IPSS using factor analysis. The resulting nine health states were valued by a representative sample of the general public (N=170) using TTO. The worst IPSS health state was valued at 0.87.


CONCLUSIONS
The values for health states defined by the IPSS revealed that LUTS suggestive of BPO has a mild impact on quality of life. The valuation of the IPSS facilitates economic evaluations of treatments for LUTS suggestive of BPO, because QALYs (the preferred outcome measure in health economics) can be determined empirically.
Kok
Esther T
ET
Institute for Medical Technology Assessment, Erasmus University Rotterdam, P.O. BOX 1738, 3000 DR Rotterdam, The Netherlands.
McDonnell
Joseph
J
Stolk
Elly A
EA
Stoevelaar
Herman J
HJ
Busschbach
Jan J V
JJ
D000328:Adult; D000368:Aged; D003362:Cost-Benefit Analysis; D005163:Factor Analysis, Statistical; D006801:Humans; D008297:Male; D008875:Middle Aged; D011470:Prostatic Hyperplasia / Q000145:classification* / Q000150:complications / Q000191:economics / Q000628:therapy; D011788:Quality of Life; D019057:Quality-Adjusted Life Years; D012720:Severity of Illness Index; D014524:Urethral Obstruction / Q000145:classification* / Q000191:economics / Q000209:etiology / Q000628:therapy