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Biomedical subjects

Anne Holbrook

Publications and source records attributed to Anne Holbrook.

13 recordsLinked to original sources
PubMed2006

Does celecoxib potentiate the anticoagulant effect of warfarin? A randomized, double-blind, controlled trial.

BACKGROUND: The management of patients who are receiving warfarin therapy and have musculoskeletal problems that require treatment with a nonsteroidal antiinflammatory drug (NSAID) is problematic because NSAID use may increase the risk for bleeding. Cyclooxygenase-2 selective NSAIDs such as celecoxib may be less likely to promote gastrointestinal bleeding; however, there are concerns that they could potentiate the anticoagulation effect of warfarin. OBJECTIVE: To determine whether celecoxib potentiates the anticoagulant effect of warfarin, as measured by the international normalized ratio (INR). METHODS: We performed a randomized, controlled, crossover trial to assess the effect on INR of celecoxib versus codeine (control treatment) in 15 patients who were receiving warfarin therapy and required analgesic treatment for osteoarthritis. During Phase 1 of the study, patients were randomly allocated to receive celecoxib 200 mg/day or codeine phosphate 7-15 mg 3-4 times daily for 5 weeks. During Phase 2 of the study, patients stopped the first study medication and started the other study medication; there was no drug-free interval between phases. Weekly INR testing was performed during the 10 week study period. Adopting the intent-to-treat principle, we used generalized estimating equations to analyze the data. RESULTS: There was no significant difference in the mean INR values during each 5 week treatment period when patients received either celecoxib or codeine. There was, therefore, insufficient evidence to reject the hypothesis that these 2 treatments had an equal effect on the INR (mean difference [95% CI] 0.10 [-0.04 to 0.24]; p = 0.16) based on mean imputation. This finding was confirmed after we repeated the analysis with multiple imputations (mean difference [95% CI] 0.093 [-0.16 to 0.35]; p = 0.47). CONCLUSIONS: Our results suggest that treatment with celecoxib does not potentiate the INR when taken with warfarin. Larger randomized trials are warranted to address the effects of coadministered warfarin and celecoxib on clinical outcomes.

Aged↗
PubMed2006

Systematic overview of drug interactions with antidepressant medications.

OBJECTIVE: Antidepressants are commonly used drugs with potential for numerous drug interactions. This study aims to systematically review the literature on drug interactions with antidepressants. METHODS: We searched MEDLINE (1966 to November 2003) and EMBASE (1980 to 2003), using the heading drug interactions combined with individual antidepressant names. We restricted searches to English-language articles and human studies. We screened drug interaction texts and review articles for relevant studies. We included articles reporting original human data on drug interactions with antidepressants commonly used in North America. Articles were independently evaluated by 2 reviewers on clinical effect, clinical significance, and quality of evidence. Discrepancies were resolved by consensus. RESULTS: There were 904 eligible interactions, involving 9509 patients, for a total of 598 summary interactions. Of these, 439 (73%) demonstrated an interaction, 148 (25%) had no effect, and 11 (2%) had conflicting evidence. For 510 interactions (85%), the quality of evidence was poor. It was fair for 67 (11%) interactions and good for 10 (2%) interactions. There were no interactions with excellent quality of evidence. There were 145 (24%) interactions of major clinical significance. These were predominantly hypertensive emergencies and serotonin syndrome. Most interacting drugs had central nervous system (CNS) activity. As expected, monoamine oxidase inhibitors (MAOIs) appear to be the most problematic family in terms of potential for serious drug interactions. CONCLUSIONS: Drug interactions with antidepressants are an important cause for concern, but this concern is based primarily on poor evidence. We recommend caution when combining antidepressants with other CNS drugs, particularly when coadministering MAOIs with other substances.

Cytochrome P-450 Enzyme System↗
PubMed2006

The role of antimalarials in the exacerbation of psoriasis: a systematic review.

OBJECTIVE: To critically review the body of literature that refutes or supports the role of antimalarials in the exacerbation of psoriasis. METHODS: MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were reviewed to identify English-language publications from 1966-2005 examining the role of antimalarials in the exacerbation of psoriasis. A total of 374 articles were identified, of which 32 studies met the inclusion criteria. All available clinical trials or reported cases of the use of antimalarials for patients with psoriasis were included. Data from clinical studies were summarized according to the level of evidence and the outcome of the study. Data were entered into a standardized data extraction form by two independent reviewers. RESULTS AND CONCLUSION: No randomized trial evidence was found. Only one cohort study was available for review. A total of 31 case series and case reports were obtained. There is no strong evidence to refute or support the role of antimalarials in the exacerbation of psoriasis. Controlled trials of antimalarial therapy and its effect on psoriasis are warranted.

Antimalarials↗
PubMed2005

Can current electronic systems meet drug safety and effectiveness requirements?

BACKGROUND: Every health policy jurisdiction is endeavoring to enhance its ability to evaluate drug effectiveness, safety and cost in the real world (pharmacosurveillance). METHODS: A nominal group consensus conference of stakeholders finalized data items deemed necessary for pharmacosurveillance. Large administrative datasets (LADs), electronic health records (EHRs) and electronic patient registries (PRs), were investigated as sources of this information and for their vulnerability to methodologic bias. Health data privacy legislation and research guidelines were systematically reviewed for their constraint to linked data resource analyses. RESULTS: More than 129 data items were strongly recommended for routine pharmacosurveillance. LADs had very complete information, but restricted to a small number of required data items. EHRs, especially with e-pharmacy links, offer by far the most complete set of health information domains but data entry completeness is highly variable. Adjustment methods for channeling bias are inadequate to mimic randomized trials. Anonymized, linked data held within a secure academic research environment, poses the least privacy concerns. CONCLUSIONS: Notwithstanding major technical, methodologic and privacy challenges, individual-level linkage of health data resources poses the best option for pharmacosurveillance today. In future, drug regulators and reimbursement agencies should consider mandatory post-marketing randomized trials.

Adverse Drug Reaction Reporting Systems↗
PubMed2004

Placebos: our most effective therapy?

Placebos remain highly controversial therapies largely because of their widespread use in research as a comparator rather than a focus of analysis. While a recent systematic review of placebo versus no therapy arms in trials found no difference, the placebo effect in some areas of drug trial research is large and increasing. We attempt to explain this paradox and suggest how clinicians may use the placebo effect to advantage.

Humans↗
PubMed2004

Application of data mining techniques in pharmacovigilance.

AIMS: To discuss the potential use of data mining and knowledge discovery in databases for detection of adverse drug events (ADE) in pharmacovigilance. METHODS: A literature search was conducted to identify articles, which contained details of data mining, signal generation or knowledge discovery in relation to adverse drug reactions or pharmacovigilance in medical databases. RESULTS: ADEs are common and result in significant mortality, and despite existing systems drugs have been withdrawn due to ADEs many years after licensing. Knowledge discovery in databases (KDD) is a technique which may be used to detect potential ADEs more efficiently. KDD involves the selection of data variables and databases, data preprocessing, data mining and data interpretation and utilization. Data mining encompasses a number of statistical techniques including cluster analysis, link analysis, deviation detection and disproportionality assessment which can be utilized to determine the presence of and to assess the strength of ADE signals. Currently the only data mining methods to be used in pharmacovigilance are those of disproportionality, such as the Proportional Reporting Ratio and Information Component, which have been used to analyse the UK Yellow Card Scheme spontaneous reporting database and the WHO Uppsala Monitoring Centre database. The association of pericarditis with practolol but not with other beta-blockers, the association of captopril and other angiotensin-converting enzymes with cough, and the association of terfenadine with heart rate and rhythm disorders could be identified by mining the WHO database. CONCLUSION: In view of the importance of ADEs and the development of massive data storage systems and powerful computer systems, the use of data mining techniques in knowledge discovery in medical databases is likely to be of increasing importance in the process of pharmacovigilance as they are likely to be able to detect signals earlier than using current methods.

Data Collection↗
PubMed2004

Patients' consent preferences regarding the use of their health information for research purposes: a qualitative study.

OBJECTIVE: To explore the consent preferences of patients whose health data are currently being used for research purposes. METHODS: Semi-structured interviews were conducted with 17 patients whose primary physicians were taking part in a study that utilized de-identified individual-level health information from their electronic medical record. All physicians practised in southwestern Ontario. All interviews were taped, transcribed verbatim and analysed using a constant comparative method. All transcripts and debriefing notes were read and reread to elicit general themes. RESULTS: Three main themes emerged from the data: patients recognized the need to balance their consent preferences with time pressures in the clinical encounter when deciding the nature of consent for a study; patients generally regarded the seeking of consent as being an issue of respect for them as individuals; and patients were also weighing their perceived benefits and concerns related to the research. For these patients, seeking their consent was an important step in research participation. For some patients, the sponsor and the research topic were factors that would influence their decision to provide consent. CONCLUSION: Patients want their consent to be sought when their data are used for research purposes. This will involve explicitly informing patients that a study is taking place, providing written consent and offering regular updates about the study.

Access to Information↗
PubMed2003

Applying methodology to electronic medical record selection.

BACKGROUND: Given the potential for electronic medical records (EMRs) to influence every aspect of health care, there has been surprisingly little rigorous research applied to this emerging health technology. An initial phase of the COMPETE (computerization of medical practices for the enhancement of therapeutic efficacy) program, which investigates the impact of EMRs and electronic decision support on efficiency, quality of care and privacy concerns, developed and used a rigorous approach to EMR selection. METHODS: A multidisciplinary team with clinical, technical and research expertise led an eight-stage evaluation process with direct input from potential clinical users at each stage. An iterative sequence of review of EMR specifications and features, live product demonstrations, site visits, and negotiations with vendors led to a progressive narrowing of the field of eligible EMR systems. Final scoring was based on three main themes of clinical usability, data quality and vendor maturity issues. RESULTS: The field of eligible EMR systems was relatively easily narrowed to a few finalists. Determination of the important strengths and weaknesses of these systems' usability, data extraction capabilities and vendor viability, required the full suite of evaluation steps. Preferences varied amongst clinicians and between clinicians and technical specialists, particularly regarding the importance of user interface versus database issues. However, the final scoring process showed consensus amongst clinical and technical experts. CONCLUSION: A rigorous, multidisciplinary process is useful in EMR selection. While prolonged and laborious, it is transparent, enhances buy in and realism of expectations by multiple potential users and IT support staff and may, therefore, improve the ultimate success of any EMR implementation project.

Computer Systems↗
PubMed2003

What factors determine the success of clinical decision support systems?

Computerized decision support systems (CDSS) which improve the quality of patient care are strong and necessary incentives for clinicians to use electronic medical records. We have noted previously that the logical path of CDSS design, which would be to determine the factors that predict success before the system is designed, appears rarely to have been followed. In this overview update of the literature on predictors of successful CDSS, we conclude that the predictors have not been adequately identified and the success of CDSS may improve when they are.

Artificial Intelligence↗
PubMed2002

Adverse events associated with pyrazinamide and levofloxacin in the treatment of latent multidrug-resistant tuberculosis.

BACKGROUND: The current Canadian and US guidelines for the treatment of multidrug-resistant latent tuberculosis infection advocate the use of pyrazinamide and a fluoroquinolone as a first-line treatment option. However, there is very little information in the literature that describes the use of these agents together. This case series describes the probable association between multiple adverse events and the use of pyrazinamide and levofloxacin in the treatment of individuals with suspected latent multidrug-resistant tuberculosis infection. METHODS: We studied a case series of 17 individuals with suspected latent multidrug-resistant tuberculosis infection in Hamilton, Ont., who were being treated with pyrazinamide and levofloxacin. The Naranjo scale was used to assess patients for musculoskeletal, central nervous system, gastrointestinal and dermatological adverse events. Hepatocellular events were assessed and defined using criteria established by the Council for International Organizations of Medical Sciences. Laboratory abnormalities and adverse events that were documented during combination drug therapy were evaluated to determine the likelihood of an association. RESULTS: Fourteen individuals developed musculoskeletal adverse effects (11 were deemed to be probably related to combination therapy). There were 8 reports of central nervous system effects (5 of which were assessed as being probably associated with therapy). Hyperuricemia and gastrointestinal and dermatological effects were also common; the use of pyrazinamide and levofloxacin was believed to be probably responsible for the emergence of these adverse effects. There were 5 cases of hepatocellular injury. Therapy was discontinued in all individuals. INTERPRETATION: The combination of pyrazinamide and levofloxacin appears to be a poorly tolerated regimen. The mechanism of a possible interaction is not yet understood. Given the severity of some of the adverse events, a better understanding of dosing and clearer guidelines for monitoring therapy are imperative if these drugs are to be prescribed together.

Adolescent↗