A. Gafni

Effects of labelling on income, work and social function among hypertensive employees☆

Two hundred and thirty hypertensive Canadian steelworkers were followed for 5 years after screening and referral. Data on income, absenteeism and measures of work and social function were collected on these men and on a matched group of 230 normotensive employees. In the fifth year after screening, hypertensive employees earned an average of Can.

Development and testing of a decision board to help clinicians present treatment options to lupus nephritis patients in Brazil

1093 less than normotensive employees despite similar incomes in the year before screening. This adverse effect on income was observed regardless of awareness of hypertension at the time of screening or compliance with treatment. Illness-related absenteeism among hypertensives rose in the year following screening and remained elevated for 4 years after screening. Normotensive and hypertensive employees reported similar levels of physical ability and psychological well-being. These findings need verification in other settings before inclusion in cost-effectiveness analyses of the management of hypertension.

A geometric confidence ellipse approach to the estimation of the ratio of two variables.

OBJECTIVE Decision boards (DBs) help clinicians present options and include patients in the decision-making process. Our objective was to describe the steps to develop a DB to support shared decision making and assess reliability and construct validity. METHODS Systemic lupus erythematosus (SLE) scenarios were designed with the support of experts for disease severity, potential side effects, and outcomes. The DB comprised clinical information, 2 different treatment options (oral and intravenous), a description of the potential to control SLE within 5 years, and a list of potential side effects. Patients selected what they thought would be the 3 worst side effects and were informed of the probability that these would occur. We presented the DB to 172 patients who were asked to select and justify 1 treatment option. Reliability was assessed by kappa statistics. Construct validity was tested by an a priori hypothesis, analyzing the correlation between treatment decision and side effects selected, self-assessment score, educational level, and clinical aspects. RESULTS Patients favored oral medication, and side effects most often listed were iatrogenic cancer (44.2%), hair loss (21.6%), and severe infection (19.1%). Justifications were risk (48.9%), practicality (36.6%), effectiveness (12.2%), and risk-benefit tradeoff (2.3%). Reliability was similar to that found in the test phase (kappa = 0.689, P < 0.001). Validity was tested by prediction of treatment decision based on the undesirable side effects selected (P = 0.047). DB content was clear and easy for all patients to understand (P = 0.05). Immunosuppressive drugs influenced patient decisions (P = 0.006). CONCLUSION DB is a reliable and valid instrument to assess SLE patient preference.

The Use of a Decision Board to Elicit Brazilian Patients' and Physicians' Preferences for Treatment: The Case of Lupus Nephritis

One is often interested in the ratio of two variables, for example in genetics, assessing drug effectiveness, and in health economics. In this paper, we derive an explicit geometric solution to the general problem of identifying the two tangents from an arbitrary external point to an ellipse. This solution permits numerical integration of a bivariate normal distribution over a wedge-shaped region bounded by the tangents, which yields an evaluation of the tangent slopes as confidence limits on the ratio of the component variables. After suitable adjustment of the confidence coverage of the ellipse, these confidence limits are shown to be equivalent to those from Fiellers method. However, the geometric approach allows additional interpretation of the data through identification of the points of tangency, the ellipse itself, and expressions for the coverage probability of the confidence interval. Numerical evaluations using the theoretical expressions for the geometric confidence intervals (but ignoring sample variation in the underlying parameters) suggested that they perform well overall and are slightly conservative. Simulations that do take account of sample variation in the underlying parameters again suggested that the intervals perform well overall, although here they are slightly anti-conservative. Coverage probabilities for the confidence intervals were only weakly dependent on the distance and correlation of the ellipse, but there were asymmetries in the failure rates of the upper and lower confidence limits in some configurations. The probability of no real solution existing was also evaluated. These ideas are illustrated by a practical example.

Guidelines for the adoption of new technologies: a prescription for uncontrolled growth in expenditures and how to avoid the problem

OBJECTIVES To find preferences for treatment expressed by lupus patients and physicians (who were asked to assume they have lupus) and to explore if certain variables explain these preferences. METHODS One hundred seventy-two patients and 202 physicians were interviewed using a lupus nephritis decision board that describes the treatment options and their potential benefits and risks. Clinical and sociodemographic variables were collected. Participants were asked to indicate their preferred treatment and provide justification for their choice. Descriptive statistics, t tests, and Pearsons chi-square tests were used to determine the significance of differences in the decisions made by the two groups. A logistic regression model determined which factors contributed to treatment decisions. RESULTS The average age of study participants was 34 ± 8 years for patients and 31 ± 7 years for physicians. Sixty-eight percent of patients and 96% of physicians (P < 0.001) selected the oral option. Patients and physicians justified their choice of treatment using different arguments (P < 0.001 in each case). Logistic regression showed that risk potential (P < 0.001) and a history of joint involvement (P = 0.011) were the arguments used most often to explain a patients decision and the risk of side effects was most relevant among physicians (P < 0.001). CONCLUSIONS Using a decision board, patients and physicians were found to have different preferences for treatment when faced with the same treatment options. Further, the variables that influence their preferences are different.