Measuring melasma patients' quality of life using willingness to pay and time trade-off methods in thai population

A cross-sectional descriptive study was conducted. Seventy-eight patients with melasma who attended the melasma clinic at Siriraj Hospital from February to March 2009 were recruited in this study. The Thai version of the DLQI, questionnaires about WTP, standard TTO, and daily TTO were used to assess patients' quality of life.Seventy-seven (98.7%) patients were female with a mean age of 47.8 ± 7.9 years. The mean health utility based on standard TTO was 0.96. The utility obtained by the daily TTO method was 0.92 and was significantly correlated with an economically inactive occupation (p < 0.05). The mean monthly WTP for the most effective treatment was 1,157 baht (7.2% of monthly income), ranging from 100 to 5,000 baht (1 USD ~ 35.1 baht). The WTP was significantly correlated with monthly personal income and the total DLQI score.The WTP method could be a useful tool with which to measure the quality of life of patients with melasma.Melasma is a common hyperpigmentation disorder that occurs on sun-exposed areas of the skin, most commonly involving the cheeks, nose, forehead, and chin. Melasma affects more non-Caucasians than Caucasians [1-3]. In 2007, 1,169 melasma patients attended Siriraj Hospital (4.1% of all dermatological outpatients). Melasma usually begins with brownish macules and progresses to patches with well-defined borders. The brownish patches have no surface scale and have a symmetric distribution [4]. Melasma can have a significant effect on an individual's quality of life as it usually affects the face and causes disfiguring lesions [5]. The Melasma Area Severity Index (MASI) is used by physicians to evaluate the severity of melasma; however, this index does not indicate the effect of melasma on the patients' quality of life [6,7]. Dermatologists should incorporate health-related quality of life measurements to help assess and monitor the progression of their patients [8,9]. Treatment of melasma is challenging because of the chronic and persistent na