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Background: Willingness to pay (WTP) and time trade-off (TTO) have been used successfully as quality of life (QOL) measurements in dermatology. However, until now there have been no studies available individually comparing these measures pre- and post-treatment., Objectives: To check sensitivity to changes for WTP and TTO (i). pre- to post-treatment, and (ii). to a 6-month follow-up period., Methods: We performed a prospective multicentre study in outpatients with psoriasis vulgaris treated with synchronous balneo-phototherapy (simultaneous application of narrowband ultraviolet B and bathing in 10% Dead Sea salt solution). Besides WTP and TTO, the Psoriasis Disability Index (PDI) and the Psoriasis Area and Severity Index (PASI) were monitored., Results: One hundred and ninety-four patients participated in the pretreatment survey, of whom 138 (71%; 84 men, 54 women; mean age 43.9 years) also returned the post-treatment questionnaire. WTP (percentage of monthly income) was shown to be independent of patients' income. During treatment, mean +/- SD WTP fell from 13.8 +/- 19.2% to 11.5 +/- 15.9% (relative improvement 16.7%; P < 0.05), TTO (h per day) from 2.7 +/- 3.8 to 2.3 +/- 3.6 (relative improvement 15%; P < 0.001), PDI improved from 29.8 +/- 18.6 to 23.5 +/- 18.9 (relative improvement 21.1%; P < 0.001) and PASI (available for 113 patients) from 14.9 +/- 7.7 to 5.6 +/- 5.0 (relative improvement 62.4%; P < 0.001). Changes in WTP, PDI and PASI were statistically significantly correlated. Ninety-one of 138 patients (66%) also completed a third survey after a follow-up period: no further changes in PDI, WTP and TTO were found, indicating a stable QOL post-treatment., Conclusions: Correlation analysis indicated that WTP, assessed as percentage of monthly income, seems to be an appropriate way to measure QOL, unbiased by income of patients. WTP, TTO and PDI were correlated and were sensitive to changes during treatment. WTP and TTO therefore also seem to be appropriate tools for assessment of QOL in interventional studies, especially for pharmacoeconomic analyses.

Background: Pharmacoeconomic outcome research is based on three criteria: (i) evaluation of objective therapeutic effects; (ii) quality of life; and (iii) treatment costs. Evaluation of therapeutic effect is mainly based on the results of clinical trials using objective clinical measures, e.g: Psoriasis Area and Severity Index (PASI) (score for psoriasis vulgaris) and the Severity Scoring of Atopic Dermatitis (SCORAD) (score for atopic dermatitis). In most studies, only results for a treatment-optimized subpopulation (patients treated according to the protocol) are presented in publications. The relevance of such data for daily routine therapy is doubtful., Objectives: Our purpose was to investigate the expected loss of effectiveness of switching from a clinical trial to daily routine therapy for the synchronous application of narrow-band ultraviolet (UV) B phototherapy (311 nm) and bathing in 10% Dead Sea salt solution (synchronous balneophototherapy) for patients with psoriasis vulgaris and atopic dermatitis., Methods: We conducted a multicentre, uncontrolled observational study of outpatients. To achieve data for 'clinical trial' and 'daily routine' situations, two populations were compared: (i) all patients strictly treated according to the protocol (ATP) with no protocol deviations (data published in clinical trials), and (ii) all patients participating in the study who received active treatment at least once, despite treatment irregularities, non-compliance, early withdrawal or other protocol violations [intention-to-treat-population (ITT), model for 'daily routine']., Results: A total of 2526 patients were included in the ITT analysis for psoriasis vulgaris (n = 487 for atopic dermatitis), of which 818 patients could be analysed according to protocol (n = 104 for atopic dermatitis). Striking differences in the therapeutic effect between both groups (ITT and ATP) were found using relative PASI and SCORAD score improvement: 11% (57% 'daily routine' vs. 68% in 'clinical trial') for psoriasis vulgaris and 16% (39% 'daily routine' vs. 55% 'clinical trial') for atopic dermatitis. The main reasons for excluding patients from the 'clinical trial' group were early study withdrawal in 29% (atopic dermatitis, 47%) of patients and fewer treatments per week than planned in the protocol in 24% (atopic dermatitis, 52%)., Conclusions: Our data clearly indicate that for the prediction of the therapeutic effect for daily routine therapy the ITT data appear to be more relevant than the ATP results (i.e. those presented in clinical trials). Although these data are only a first step for evaluating the 'real' therapeutic effect of a treatment modality in daily routine, they seem to support the requirements for ITT analyses in efficacy studies and demonstrate the necessity of ITT data for pharmacoeconomic evaluation.