Paul Grootendorst

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BACKGROUND The Health Utilities Index Mark 3 (HUI3) is a comprehensive, compact health status classification and health state preference system. The HUI3 system has been included in 4 Canadian population health surveys and numerous clinical trials. OBJECTIVES To evaluate the construct validity of the HUI3 for the measurement of health-related quality of(More)
The price elasticity of demand for prescription drugs is a crucial parameter of interest in designing pharmaceutical benefit plans. Estimating the elasticity using micro-data, however, is challenging because insurance coverage that includes deductibles, co-insurance provisions and maximum expenditure limits create a non-linear price schedule, making price(More)
OBJECTIVE To develop a formula to translate Western Ontario and McMaster University Osteoarthritis Index (WOMAC) scores collected in clinical trials of patients with osteoarthritis (OA) into Health Utilities Index Mark 3 (HUI3) utility scores for application in economic evaluation. METHODS Data from a previously published open-label randomized controlled(More)
We show the estimable rational addiction model tends to yield spurious evidence in favor of the rational addiction hypothesis when aggregate data are used. Direct application of the canonical model yields results seemingly indicative that non-addictive commodities such as milk, eggs, and oranges are rationally addictive. Monte Carlo simulation demonstrates(More)
The propensity score--the probability of exposure to a specific treatment conditional on observed variables--is increasingly being used in observational studies. Creating strata in which subjects are matched on the propensity score allows one to balance measured variables between treated and untreated subjects. There is an ongoing controversy in the(More)
OBJECTIVE To examine the validity of a newly developed prediction model translating osteoarthritis (OA)-specific health-related quality of life (HRQL) scores measured using the Western Ontario and McMaster Osteoarthritis Index (WOMAC) into generic utility-based HRQL scores measured using the Health Utilities Index Mark 3 (HUI3). METHODS Preintervention(More)
Using recent Canadian health survey data, we investigated the effect of socioeconomic status on patients' use of dental services and dental insurance coverage. Our results point to an important socioeconomic gradient in the use of dental services. The probability of receiving any dental care over the course of a year increases markedly with dental(More)
A major, often unstated, concern of researchers carrying out epidemiological studies of medical therapy is the potential impact on validity if estimates of treatment are biased due to unmeasured confounders. One technique for obtaining consistent estimates of treatment effects in the presence of unmeasured confounders is instrumental variables analysis(More)
BACKGROUND Reference-based pricing limits reimbursement for a group of drugs that are deemed therapeutically equivalent to the cost of the lowest-priced product within that group. We estimated the effect of reference-based pricing of nitrate drugs used for long-term prophylaxis on prescribing of and expenditures on nitrates and other anti-anginal drugs(More)
The cost of alternative dialysis modalities for the treatment of end-stage renal disease (ESRD) was evaluated, using a societal viewpoint, in a regional nephrology program in south-western Ontario. The dialysis treatments compared were hospital hemodialysis, home hemodialysis, self-care hemodialysis, and continuous ambulatory peritoneal dialysis (CAPD). The(More)