RESUMEN
BACKGROUND: During the past 15 years there has been an exponential increase in the number of prescriptions for lipid-lowering drugs. Uncertainties remain about the long-term impact of these medications on cancer, which is particularly bothersome given that the duration of these treatments may extend for several decades. OBJECTIVE: To explore the association between 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors and cancer incidence. METHODS: Using the administrative health databases of the Régie de l'Assurance-Maladie du Québec we performed a nested case-control study. We selected a cohort of 6721 beneficiaries of the health care plan of Quebec who were free of cancer for at least 1 year at cohort entry, 65 years and older, and treated with lipid-modifying agents. Cohort members were selected between 1988 and 1994 and were followed up for a median period of 2.7 years. From the cohort, 542 cases of first malignant neoplasm were identified, and 5420 controls were randomly selected. Users of HMG-CoA reductase inhibitors were compared with users of bile acid-binding resins as to their risk of cancer. Specific cancer sites were also considered. RESULTS: Users of HMG-CoA reductase inhibitors were found to be 28% less likely than users of bile acid-binding resins to be diagnosed as having any cancer (rate ratio, 0.72; 95% confidence interval, 0.57-0.92). All specific cancer sites under study were found to be not or inversely associated with the use of HMG-CoA reductase inhibitors. CONCLUSION: The results of our study provide some degree of reassurance about the safety of HMG-CoA reductase inhibitors.
Asunto(s)
Inhibidores de Hidroximetilglutaril-CoA Reductasas/efectos adversos , Hipolipemiantes/efectos adversos , Neoplasias/inducido químicamente , Sistemas de Registro de Reacción Adversa a Medicamentos , Anciano , Estudios de Cohortes , Femenino , Humanos , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Hipolipemiantes/uso terapéutico , Cuidados a Largo Plazo , Masculino , Quebec , RiesgoRESUMEN
OBJECTIVE: To assess prescription renewal and switch rates in an elderly population receiving oxybutynin or flavoxate for treatment of urinary incontinence in Quebec. METHODS: Sociodemographic, clinical, and drug claim data for patients > or = 65 years of age, with at least one claim for oxybutynin or flavoxate between January 1, 1994 and December 31, 1997, were randomly extracted from a database maintained by the Régie de l'assurance maladie du Québec (RAMQ). Rates of renewal of the first drug claim and the number of patients switching from one incontinence drug to the other were determined. In addition, survival curves defining the time until cessation of initial treatment were constructed. RESULTS: The oxybutynin (n = 5718) and flavoxate (n = 972) treatment groups were similar in terms of gender (62.1% female) and age (mean age 77). For oxybutynin, 56.8% of the claims were written by general practitioners and 36.6% by urologists compared to 40.5% by general practitioners and 51.4% by urologists for flavoxate. Only 39.3% of the oxybutynin patients renewed their first claims, compared to 36.6% of the flavoxate group. Switch rates were higher for flavoxate patients with more than twice as many patients switching from this drug to oxybutynin than vice versa. Survival curves indicated that there was only an 11.4% probability of a patient taking oxybutynin for 6 months compared to 5.7% for flavoxate patients. CONCLUSIONS: Drug claim renewal rates were low for both oxybutynin and flavoxate, suggesting that money spent on these therapies provides an inadequate clinical return on investment since the majority of patients discontinue treatment prematurely.
RESUMEN
In pharmacoeconomics, the comparison of the costs of 2 different drugs used for the same treatment is of great interest. The problem is especially challenging when the drugs are likely to produce costly adverse effects in a small number of patients, which is often the case. The data are then skewed and traditional statistical methods to analyse the difference in the mean costs produced by 2 treatments may be inappropriate. The bootstrap method is presented as an alternative approach. A pharmacoeconomic cost-analysis example is presented and used throughout this article.