A population-based assessment of the drug interaction between levothyroxine and warfarin.

Most drug interaction resources suggest that levothyroxine can dramatically potentiate the effect of warfarin. However, the mechanistic basis of the interaction is speculative, and little evidence supports a meaningful drug interaction. We conducted a population-based nested case-control study to examine the risk of hospitalization for hemorrhage following the initiation of levothyroxine in a cohort of 260,076 older patients receiving warfarin. In this group, we identified 10,532 case subjects hospitalized for hemorrhage and 40,595 controls. In the primary analysis, we found no association between hospitalization for hemorrhage during warfarin therapy and initiation of levothyroxine in the preceding 30 days (adjusted odds ratio 1.11, 95% confidence interval 0.67-1.86). Secondary analyses using more remote initiation of levothyroxine also found no association. These findings suggest that concerns about a clinically meaningful levothyroxine-warfarin drug interaction are not justified. Drug interaction resources that presently characterize this interaction as important should reevaluate this classification.

Osteoporosis medication prescribing in British Columbia and Ontario: impact of public drug coverage.

UNLABELLED: We compared the patterns of osteoporosis medication prescribing between two provinces in Canada with different public drug coverage policies. Oral bisphosphonates were the primary drugs used, yet access to the second-generation oral bisphosphonates (alendronate, risedronate) was limited in one region. Implications of differential access to oral bisphosphonates warrants further study. INTRODUCTION: Approved therapies for treating osteoporosis in Canada include bisphosphonates, calcitonin, denosumab, raloxifene, and teriparatide. However, significant variation in access to these medications through public drug coverage exists across Canada. We sought to compare patterns of osteoporosis medication prescribing between British Columbia (BC) and Ontario. METHODS: Using dispensing data from BC (PharmaNet) and Ontario (Ontario Drug Benefits), we identified all new users of osteoporosis medications aged 66 or more years from 1995/1996 to 2008/2009. We summarized the number of new users by fiscal year, sex, and index drug for each province. BC data were also stratified by whether drugs were dispensed within or outside public PharmaCare. RESULTS: We identified 578,254 (n = 122,653 BC) eligible new users. Overall patterns were similar between provinces: (1) most patients received an oral bisphosphonate (93% in BC and 99% in Ontario); (2) etidronate prescribing declined after 2001/2002, reaching a low of 41% in BC and 10% in Ontario in 2008/2009; and (3) the proportion of males treated increased over time, from 7% in 1996/1997 to 25% in 2008/2009. However, we note major differences within versus outside the BC PharmaCare system. In particular, <2% of drugs dispensed within PharmaCare compared to 79% of drugs dispensed outside PharmaCare were for a second-generation bisphosphonate (alendronate or risedronate). CONCLUSIONS: Oral bisphosphonates are the primary drugs used to treat osteoporosis in Canada. Prescribing practices changed over time as newer medications came to market, yet access to second-generation bisphosphonates through BC PharmaCare was limited. Implications of differential access to oral bisphosphonates warrants further study.

Role of family physicians in hospitals. Did it change between 1977 and 1997?

OBJECTIVE: To investigate whether hospital activities and attitudes toward hospitals of members of an urban family medicine department changed between 1977 and 1997. To explore whether these activities and attitudes are different among fee-for-service (FFS) and non-FFS physicians in 1997. DESIGN: Cross-sectional surveys by interview (1977) and self-administered questionnaire (1997). SETTING: Community-based family practices in Hamilton, Ont. PARTICIPANTS: In 1977, 88 of 89 (98.9%) and, in 1997, 66 of 88 (75.0%) members of the Department of Family Medicine at St Joseph's Hospital in Hamilton. MAIN OUTCOME MEASURES: Perceived reasons for involvement in hospital work; time spent and main activities in hospital; use of hospital privileges; attitudes toward family physicians' role in hospital, hospital work, and the Department of Family Medicine; perceptions of patients', consultants', and hospital administrators' attitudes toward family physicians' role in hospitals. RESULTS: In 1977 and 1997, patient care and continuing education remained key reasons for doing hospital work. In 1997, however, respondents spent a mean of 3 hours less per week in hospital; used the hospital less often for procedures, meetings, and teaching; and assumed less responsibility for their patients' in-hospital care. While perceptions of hospital work changed over the years, most physicians continued to see a need and have a desire to remain involved in hospitals. Fee-for-service and non-FFS physicians held different opinions on the needs of both hospitalized patients and family physicians. CONCLUSION: Although physicians' hospital activities and attitudes changed between 1997 and 1997, most continued to see a need and have a desire to remain involved in hospitals.

Ontario hospitals' purchasing practices for hip and knee prostheses: a survey.

OBJECTIVES: To determine the makes, models and prices of the implants provided by Ontario hospitals for hip and knee replacements and the policies and procedures governing purchases. DESIGN: A questionnaire survey of hospitals with telephone follow-up. STUDY POPULATION: Seventy-nine public hospitals in Ontario in which 10 or more hip or knee replacements were carried out in the fiscal year 1993/94. SURVEY RESPONSE: Seventy-six hospitals returned questionnaires (96% response rate), reporting on 4950 primary hip and 5107 primary knee implants. Sixty-two hospitals reported volumes and prices for 19 models used in 2961 hip implants. Information on price but not makes and models was available for 1989 hip implants. Model and price information was missing for 340 hip prostheses. Fifty-seven hospitals identified the models and prices for 3460 knee implants. Twenty-five hospitals provided prices but not specific models names for 1647 knee implants and hybrids. OUTCOME MEASURE: The prices paid for prostheses. RESULTS: The average price of hip implants was Can$2141 (range from Can$650 to Can$3559). The average price for knee implants was Can$2412 (range from Can$1178 to Can$3777). The averages and ranges were about the same for specified and unspecified models and hybrids. The variations were unrelated to hospital policies about the numbers of procedures to be provided or the procedures for making purchases from suppliers. CONCLUSIONS: Savings of Can$13.7 million could have been made in Ontario during the fiscal year 1993/94 had the lowest prices been paid for the implants. Although it may be neither desirable nor possible to use the least expensive model and price in every hospital, the potential for cost reductions in the purchase of implants is substantial.