Reliability of self-reported willingness-to-pay and annual income in patients treated for toenail onychomycosis

Survey on Willingness to Pay for Life-Saving Treatment, Functional Recovery, and Cosmesis in a Neuroscience Outpatient Clinic Setting in Singapore

BACKGROUND

Neurologic disorders impose a heavy burden on healthcare in Singapore. To date, no data on the willingness to pay (WTP) for neurologic treatments has been reported in the local population.

OBJECTIVES

We aimed to quantify the value of various health domains to neuroscience patients and their caregivers by comparing their WTP for different types of treatments.

METHODS

A questionnaire using a mixed open-ended and closed-ended contingent valuation method was developed to elicit WTP and self-administered by 112 visitors to a neuroscience outpatient clinic. The WTP for treatments in 3 health domains (advanced restoration of function, life extension, and cosmesis) was evaluated and compared. Subgroup regression analysis was performed to investigate the impact of demographic and socioeconomic factors.

RESULTS

Treatment that improved cosmesis had the highest median WTP of Singapore dollar (SGD) 35 000, followed by treatment that provided 1 year of life extension (SGD 20 000) and 1 year of advanced restored function (SGD 10 000; P < .001). Respondents with a university education were willing to pay as much as 2 to 3 times of those without across all health domains.

CONCLUSION

This is the first study to provide data on how different health domains are valued by neuroscience patients and caregivers in our population. Respondents valued treatment that restored or improved their physical appearances the most. These findings could contribute to future policies on the improvement of neuroscience care.

Willingness to pay for a cure of low-risk melanoma patients in Germany

Malignant melanoma is potentially life-threatening but in most cases curable if detected early. Willingness to pay (WTP) is a preference-based construct that reflects burden of disease by assessment of the monetary value for a hypothetical cure from disease. Since WTP (directly as total amount of money) has not been assessed so far in patients with low risk melanoma, it was interesting to gain insights in this patient population and then, in a second step, compare it directly with the WTP of their treating dermato-oncologists. WTP was assessed in 125 patients with low-risk melanoma and additionally in 105 treating physicians, asking for the one-time and continuous payments they would be willing to make for a sustainable cure, both as absolute sums and as percentages of monthly income. The median WTP based on one-time payment was €10,000 for patients and €100,000 for physicians; relative numbers were 100% versus 300% of monthly income. For continuous monthly payments, WTP was €500 for patients and €1000 for physicians, relative numbers 25% and 50% of income, respectively. Even after controlling for income differences, there was a significantly higher WTP in physicians for all four questions. Compared to patients with chronic skin diseases such as vitiligo, rosacea, atopic eczema and psoriasis, patients with low-risk melanoma showed a significantly higher WTP. Our data suggest that there is a relevant burden of disease even in patients with low-risk tumors. Higher WTP of physicians underlines the prevalence of differences in disease perception.

Eliciting preferences to inform patient-centred policies: the case of psoriasis

OBJECTIVE

To assess patient preferences for psoriasis treatment features and to investigate the heterogeneity of preferences among patients with different socio-demographic and disease-related characteristics.

METHODOLOGY

A discrete choice experiment was conducted on adult patients with moderate to severe plaque-type psoriasis during a routine visit to their physician at 15 centres in Italy. We investigated the preferences of patients with respect to five treatment attributes: (1) mode and frequency of administration; (2) time to improvement; (3) time free of symptoms; (4) unintended life expectancy reduction resulting from treatment; and (5) monthly treatment cost. The heterogeneity of preferences was investigated in a mixed logit model with normally distributed random coefficients.

RESULTS

Overall, patients preferred the subcutaneous or intravenous route of administration (versus oral administration) and treatments that took less time to show improvement, ensured a longer time free of symptoms, involved a lesser reduction in life expectancy and had lower costs. There was significant preference heterogeneity for all attributes. The cost attribute was found to be significantly more important to females and to older patients (above 60 years of age). Older patients placed significantly greater emphasis on reduced life expectancy, whereas the time free of symptoms was significantly less important to them than to patients under 60 years of age. Patients with higher scores on the Dermatology Life Quality Index (DLQI) placed higher value on the time free of symptoms than those with lower DLQI scores. For the overall sample, the marginal willingness to pay (WTP) for a month's reduction in the time to improvement was <euro>32.4, whereas the WTP for one additional month without symptoms was significantly higher (<euro>68.2).

CONCLUSION

Patient-centred policies should consider the heterogeneity of patients' expectations to identify individualized treatments that would aid in optimizing patient satisfaction and wellbeing, as well as overall treatment effectiveness.

The determinants of periorbital skin ageing in participants of a melanoma case-control study in the U.K

BACKGROUND

Skin ageing is said to be caused by multiple factors. The relationship with sun exposure is of particular interest because the detrimental cutaneous effects of the sun may be a strong motivator to sun protection. We report a study of skin ageing in participants of an epidemiological study of melanoma.

OBJECTIVES

To determine the predictors of periorbital cutaneous ageing and whether it could be used as an objective marker of sun exposure.

METHODS

Photographs of the periorbital skin in 1341 participants were graded for wrinkles, degree of vascularity and blotchy pigmentation and the resultant data assessed in relation to reported sun exposure, sunscreen use, body mass index (BMI), smoking and the melanocortin 1 receptor (MC1R) gene status. Data were analysed using proportional odds regression.

RESULTS

Wrinkling was associated with age and heavy smoking. Use of higher sun-protection factor sunscreen was protective (P = 0·01). Age, male sex, MC1R variants ('r', P=0·01; 'R', P=0·02), higher reported daily sun exposure (P=0·02), increased BMI (P=0·01) and smoking (P=0·02) were risk factors for hypervascularity. Blotchy pigmentation was associated with age, male sex, higher education and higher weekday sun exposure (P=0·03). More frequent sunscreen use (P=0·02) and MC1R variants ('r', P=0·03; 'R', P=0·001) were protective.

CONCLUSIONS

Periorbital wrinkling is a poor biomarker of reported sun exposure. Vascularity is a better biomarker as is blotchy pigmentation, the latter in darker-skinned individuals. In summary, male sex, sun exposure, smoking, obesity and MC1R variants were associated with measures of cutaneous ageing. Sunscreen use showed some evidence of being protective.

Willingness-to-pay stated preferences for 8 health-related quality-of-life domains in psoriasis: a pilot study

BACKGROUND

Psoriasis is a chronic skin condition that has a major impact on health-related quality of life (QOL). We evaluated health-related QOL via willingness to pay and a ranking task for 8 domains of health relevant to psoriasis: intimacy, physical comfort, self-care, ability to work or volunteer, ability to concentrate, emotional health, social comfort, and ability to sleep.

OBJECTIVE

The goals of the study were to pilot test a new method to measure QOL impact in psoriasis and identify the areas of life most affected by psoriasis.

METHODS

Forty participants with a history of psoriasis were interviewed in a face-to-face format. First, participants were asked to rank the 8 domains of health we were investigating. Second, patients were asked how much money they would be willing to pay for a hypothetical cure for each domain of health. Responses in US dollars were interpreted as strength of preference rather than absolute monetary values.

RESULTS

About half of the patients in the sample (48%) were female, 60% had a college degree or further education, and 38% had an income level over $45,000/y. Physical comfort, social comfort, and emotional health were highly ranked by more than 75% of respondents. Ability to concentrate was least likely to be affected by psoriasis with just a quarter (25.7%) of respondents ranking this domain as important. The median amount patients were willing to pay for a hypothetical cure of psoriasis specific to a particular domain was highest for physical comfort ($2000, 25th quartile = $500, 75th quartile = $5500) and emotional health ($2000, 25th quartile = $250, 75th quartile = $5000), and lowest for ability to sleep ($625, 25th quartile = $50, 75th quartile = $5000).

LIMITATIONS

The sample size is modest for this pilot study. Willingness to pay as a method of eliciting stated preferences for qualitative aspects of health may be influenced by individual perception of money.

CONCLUSIONS

This study successfully pilot tested a willingness-to-pay method and a ranking task to measure the relative severity of 8 domains of health-related QOL and found that physical comfort, social comfort, and emotional health were the domains of health most affected by psoriasis.

Naildex: pilot evaluation of an onychodystrophy severity instrument

A valid and reliable measure that captures onychodystrophy disease severity is important for both clinical and research applications. Three hundred and twenty-two patients at two Veterans Affairs Medical Centers with clinical evidence of onychodystrophy suggesting onychomycosis (at least 25% in a distal subungual pattern) were examined using Naildex parameters. Naildex scores were calculated by a combination of: per cent of each nail infected, area of each nail and number of infected nails. Patients also completed a nail-specific quality of life questionnaire (NailQoL) and nail samples were collected and examined mycologically. Data was analysed for all enrolled patients (n = 322) and patients with mycologically-confirmed onychomycosis (n = 243). Inter-rater reliability was calculated from two examiners who each evaluated 17 patients with mycologically-confirmed onychomycosis. Significant correlations (P < 0.01) between Naildex and NailQoL as well as proxy measures (duration of infection) indicated construct validity of the instrument for all patients as well as mycologically-confirmed cases. Strong correlation (r = 0.754, P < 0.01, n = 17) indicated high inter-rate reliability. This pilot evaluation suggests that Naildex is a valid and reliable measure of onychomycosis severity.

Validity of self-reported nail counts in patients with onychomycosis: A retrospective pilot analysis

BACKGROUND

Onychomycosis (fungal infection of the toenails or fingernails) is common, affecting up to 8% of the general population. Telephone and mailed surveys conducted to study this disease are usually completed via patient self-report. The validity of the counts of diseased nails reported by the patients participating in these surveys has not been established.

OBJECTIVE

The aim of this study was to assess the interrater agreement between patient and health care professional (HCP) counts of affected nails in patients with onychomycosis.

METHODS

Patient and HCP counts of infected toenails and fingernails corresponding to a total of 567 patients originating from 3 different clinical trials were retrospectively analyzed. All these patients were initially classified as mycologically positive for toenail onychomycosis, and all 3 trials used identical self-administered questions regarding counts of infected toenails and fingernails. The level of agreement between patient versus HCP counts of infected toenails and fingernails (based on collapsed and uncollapsed counts) was measured using the quadratically weighted kappa statistic.

RESULTS

Thirty-eight percent (213/554, 95% confidence interval [CI] = 35% to 43%) of the 554 patients with self-reported and HCP counts of infected toenails had exact agreement; for these 554 patients, quadratically weighted kappa = 0.47 (95% CI: 0.40 to 0.54). The highest agreement rates-79, 62, and 50%-correspond to the patients with HCP counts of affected toenails equaling 1, 2, and 10, respectively; that is, HCP counts at the extremes. The agreement rates ranged from 3% to 31% for the remaining patients with HCP counts between 3 and 9. Patients tended to undercount affected toenails, irrespective of the number of affected toenails counted by HCPs. No statistically significant association was found between agreement rates and whether or not the patients had been previously treated for toenail onychomycosis (P = .91). A marginally nonsignificant association of increasing agreement rates with increasing disease duration was observed (P = .06). Among the patients who reported one or more affected fingernails (n = 122), percent agreement was similar to that of toenails (41%, 95% CI: 33.0 to 50.0%).

LIMITATIONS

This pilot study is limited by its retrospective design, its homogeneous group of patients (predominantly white, male veterans), and the fact that information on intraobserver and interobserver reliability was not obtained from all of the 3 clinical trials, the sources for this analysis.

CONCLUSIONS

Patients tend to undercount affected nails as compared to HCPs. Reliance on self-reported counts in epidemiological surveys may lead to an inaccurate, underestimate of disease severity.