Influence of ethnic origin on the incidence of keratoconus and associated atopic disease in Asians and white patients.

PURPOSE: To investigate the influence of ethnic origin on the incidence of keratoconus and the association of atopic diseases in patients with keratoconus. METHODS: Retrospective study of new patients referred to Dewsbury District General Hospital and diagnosed with keratoconus in a 6-year period between 1994 and 2000. The ethnic origin of the patient was defined as white, Asian, or other. Incidence was calculated from the catchment population of 176 774 (82% white people, 17% Asians, 1% others). t-Test, confidence intervals and chi2 tests were used to show statistical significance. RESULTS: A total of 74 cases of keratoconus were diagnosed over this period. Of these patients 29 (39%) were white and 45 (61%) were Asian. This equated to an incidence of keratoconus of 25 per 100 000 (1 in 4000) per year for Asians, compared with 3.3 per 100 000 (1 in 30 000) per year for white people (P<0.001). Asians presented significantly younger than white patients. The incidence of atopic disease was found to be significantly higher in white compared to Asian keratoconic patients. CONCLUSIONS: Asians were significantly more likely to present with keratoconus. The Asian patients were mostly of Northern Pakistani origin. This community has a tradition of consanguineous, especially first-cousin marriages. The higher incidence in this population was highly suggestive of a genetic factor being significant in the aetiology. The incidence was higher than revealed by previous studies. Atopic disease was significantly less common in Asians compared to white people, supporting the theory of a different aetiology in these patients.

Urge incontinence. Quality of life and patients' valuation of symptom reduction.

OBJECTIVE: Previous studies have demonstrated the effect of incontinence, and urge incontinence in particular, on patients' quality of life. This study assessed the effects of urge incontinence on quality of life and measured the value of a reduction in symptoms. DESIGN: A self-administered questionnaire was mailed to 591 patients with urge or mixed incontinence. 495 (83.8%) surveys were returned with complete quality of life and symptom data. Of the total sample, 411 patients received the willingness-to-pay (WTP) survey, from which 257 (62.53%) returns were judged complete and reliable. Information was collected about the number of micturitions and urinary leakages. Health-related quality of life (HR-QOL) was measured using the Short Form 36 (SF-36) Health Survey. Socioeconomic characteristics were also recorded. Value was assessed with a binary WTP question. MAIN OUTCOME MEASURES AND RESULTS: Quality of life among the sample population was significantly lower in 5 of 8 dimensions compared with the general US population, and was significantly related to the severity of the symptoms in 6 of 8 dimensions. The median (mean) willingness to pay was $US27.24 ($US87.74) per month for a 25% reduction in micturitions and leakages, and $US75.92 ($US244.54) per month for a 50% reduction in micturitions and leakages. As expected, the willingness to pay was significantly related to the size of the reduction in micturitions and leakages, and household income. CONCLUSIONS: Patients with incontinence perceive substantial benefits from a reduction in the number of micturitions and leakages.

Willingness to pay for reduced incontinence symptoms.

OBJECTIVE: To measure the willingness to pay for a reduction in the number of micturitions and urinary leakages for patients with urge incontinence. PATIENTS AND METHODS: A self-administered questionnaire with a binary willingness-to-pay question was administered to 541 patients in Sweden with urge or mixed incontinence; 461 questionnaires were returned. The reduction in micturitions and urinary leakages valued in the willingness-to-pay question was varied randomly between 25% and 50% in two different subsamples. Information was also collected about the number of micturitions and urinary leakage, health-related quality of life and socio-economic characteristics of the patients in the study. RESULTS: Quality of life was significantly related to the severity of the symptoms and was worse than that of the sex- and age-matched general Swedish population. The median (mean) willingness to pay per month was 240 (530) Swedish krona (SEK, 1 Pound = SEK 11.50) for a 25% reduction in micturitions and leakages and SEK 470 (1030) for a 50% reduction in micturitions and leakages. As hypothesized, the willingness to pay was significantly related to the size of the reduction in micturitions and leakages, the initial number of micturitions and leakages, and income. CONCLUSIONS: Patients with incontinence problems are willing to pay substantial amounts for a reduction in the number of micturitions and leakages.

Measurement of consumer-patient preferences using a hybrid contingent valuation method.

This study introduces a hybrid, two-stage, contingent valuation method applied to asthma treatment. Respondents are initially offered a choice between hypothetical medications, implying a tradeoff between safety and efficacy. Stage two elicits willingness to pay (WTP) for an improvement along a single risk dimension. Estimates of the value of asthma control based on the initial risk tradeoff stage range from approximately US$1400 to US$2100 per year, assuming a US $6 million value of life. Analysis of the second-stage WTP responses yield estimates for the value of a statistical life of approximately US$9 million and for asthma control of approximately US$2200 per year.

Incorporating future costs in medical cost-effectiveness analysis: implications for the cost-effectiveness of the treatment of hypertension.

It has been shown that the difference between consumption and production during life years gained should be included as a cost in cost-effectiveness analysis. In this study the authors estimate the impact of including these future costs on the cost-effectiveness of the treatment of hypertension in Sweden. The cost per quality-adjusted life year (QALY) gained changes little among young men and women due to the addition of future costs, but increases by about $14,000 for middle-aged men and women and about $27,000 for older men and women. When future costs are not included, the cost per QALY gained is generally lowest among older men and women, but when future costs are included, the cost per QALY gained is generally lowest among middle-aged men and women. The authors conclude that the total resource consequences of changes in mortality should be routinely considered in cost-effectiveness analyses.

Cost-utility analysis from a societal perspective.

In this paper, we outline how to use cost-utility analysis from a societal perspective and the arguments that could be made for using data such as a model for economic evaluation of health care. We show that to include all the costs in the analysis, a price per quality-adjusted life years (QALY) gained rather than a given budget should be used as the decision rule. Using cost-utility analysis this way is based on a willingness to pay per QALY gained that is constant and the same for everyone. To use a fixed price per QALY gained is consistent with societal utility maximization if aggregated QALYs are a measure of societal utility and if the mix of financing sources is the same for all health care programmes. If, furthermore, the price per QALY gained is set at the optimal level, cost-utility analysis will lead to a maximization of societal utility. To get more information on the willingness to pay per QALY gained so as to provide cost-utility analysis with a useful decision rule should be a research priority.