Clinical information for research; the use of general practice databases.
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General practice computers have been widely used in the United Kingdom for the last 10 years and there are over 30 different systems currently available. The commercially available databases are based on two of the most widely used systems--VAMP Medical and Meditel. These databases provide both longitudinal and cross-sectional data on between 1.8 and 4 million patients. Despite their availability only limited use has been made of them for epidemiological and health service research purposes. They are a unique source of population-based information and deserve to be better recognized. The advantages of general practice databases include the fact that they are population based with excellent prescribing data linked to diagnosis, age and gender. The problems are that their primary purpose is patient care and the database population is constantly changing, as well as the usual problems of bias and confounding that occur in any observational studies. The barriers to the use of general practice databases include the cost of access, the size of the databases and that they are not structured in a way that easily allows analysis. Proper utilization of these databases requires powerful computers, staff proficient in writing computer programs to facilitate analysis and epidemiologists skilled in their use. If these structural problems are overcome then the databases are an invaluable source of data for epidemiological studies. (+info)
Pharmacoepidemiology of non-steroidal anti-inflammatory drug use in Nottingham general practices.
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AIM: To investigate the pharmacoepidemiology of NSAID usage in Nottingham general practices. DESIGN: Questionnaire sent to 1137 consecutive recipients of an NSAID prescription from 21 doctors in six general practices with computerized records. Patient responses were subsequently linked to data held on the practice records. SETTING: General practices in and around Nottingham, selected to reflect local variations in number of partners, list size, geographical location, deprivation, prescribing burden and prescribing rate. SUBJECTS: Unselected patients receiving NSAIDs prescribed for all indications. MAIN OUTCOME MEASURES: Indication for treatment, differences in prescribing to different age groups, compliance and overall scheme drug exposure, drug effectiveness and tolerability, possible drug-related adverse events, patients' overall satisfaction with treatment and estimated costs of care. RESULTS: NSAIDs were used for a wide range of conditions and only a small number of patients had rheumatoid arthritis. The main drugs used were ibuprofen, diclofenac and naproxen. Patients making short-term use of NSAIDs had low compliance if they experienced adverse drug effects, whilst conversely in long-term users, those with high compliance reported more adverse drug effects. Calculated compliance did not vary with age although older patients (over 65 years) claimed in their questionnaires to be more compliant than younger patients. Half the patients reported good or complete symptom relief. Half of those questions (and two thirds of those with good or complete symptom relief) rated their NSAID as the best treatment they had received for their current condition. The frequency of gastrointestinal adverse events was higher in the young and the old, which correlated with the use of anti-ulcer drugs, and increased with the total number of medications used. CONCLUSIONS: NSAIDs are used for a wide-range of conditions. They give symptom relief to, and are perceived as effective by, most patients taking them. (+info)
The incidence of adverse events and risk factors for upper gastrointestinal disorders associated with meloxicam use amongst 19,087 patients in general practice in England: cohort study.
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AIMS: Meloxicam is a novel nonsteroidal anti-inflammatory drug (NSAID) which may be associated with fewer adverse upper gastrointestinal events than other NSAIDs because it preferentially inhibits the inducible enzyme cyclo-oxygenase-2 relative to the constitutive isoform, cyclo-oxygenase-1. The aims of the study were to: determine the rate of adverse events associated with meloxicam in general practice, stratify these rates by selected risk factors, and to identify signals of previously unsuspected adverse events associated with meloxicam. METHODS: As part of the national prescription-event monitoring pharmacovigilance system for newly launched drugs in general practice, all patients prescribed meloxicam in England between December 1996 and March 1997 were identified by the central Prescription Pricing Authority. We sent short questionnaires to all prescribers asking about adverse events experienced within 6 months of the first prescription. RESULTS: There were 19 087 patients in the study. The rate of dyspepsia during the first month of exposure was 28.3 per 1000 patient-months. There were 33 reports of upper gastrointestinal haemorrhage during treatment (rate: 0.4 per 1000 months). A history of gastrointestinal disorder in the previous year was associated with an increased rate of dyspepsia (rate ratio: 3.0; 95% confidence interval: 2.6, 3.4), abdominal pain (2.1; 1.6, 2.6), and peptic ulcer (4.0; 1.4, 13.2). Prior NSAID use was associated with a 20-30% decrease in the rate of dyspepsia and abdominal pain in patients starting meloxicam, while patients prescribed concomitant gastroprotective agents had a two to three-fold increased rate of dyspepsia, abdominal pain and peptic ulceration. Other rare events were thrombocytopenia (n = 2); interstitial nephritis (n = 1) and idiosyncratic liver abnormalities (n = 1). CONCLUSIONS: In the absence of gastro-intestinal risk factors the incidence of gastro-intestinal disturbance was low. Such risk factors should be carefully reviewed prior to prescribing meloxicam. (+info)
Aspirin and ovarian cancer: an Italian case-control study.
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BACKGROUND: A role for inflammation, and consequently of non-steroidal anti-inflammatory drugs, in ovarian carcinogenesis has been proposed, but epidemiological evidence is scanty. PATIENTS AND METHODS: Data were derived from a hospital-based case-control study conducted in Italy between 1992 and 1999. Cases were 749 women, aged 18-80 years (median age 56 years), with incident, histologically confirmed ovarian cancer. Controls were 898 non-hysterectomized women, aged 17-80 years (median age 58 years), admitted to hospital for acute conditions, unrelated to risk factors for ovarian cancer. RESULTS: The multivariate odds ratio (OR) was 0.93 (95% confidence interval (95% CI): 0.53-1.62) for regular aspirin use for more than six months, 1.38 (95% CI: 0.57-3.36) for current use and 0.72 (95% CI: 0.35-1.47) for former use. The OR was not significantly different from unity for duration of use, age at starting use, indication (analgesia or cardiovascular prevention), and in women aged < 60 and > or = 60 years at ovarian cancer diagnosis. CONCLUSIONS: This study provides little support for the hypothesis that aspirin may reduce the risk of ovarian cancer. (+info)
Design issues for drug epidemiology.
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Despite the difficulties involved in designing drug epidemiology studies, these studies are invaluable for investigating the unexpected adverse effects of drugs. The aim of this paper is to discuss various aspects of study design, particularly those issues that are not easily found in either textbooks or review papers. We have also compared and contrasted drug epidemiology with the randomized controlled trial (RCT) wherever possible. Drug epidemiology is especially useful in the many situations where the RCT is not suitable, or even possible. The study base has to be defined before the appropriate cohort of subjects is assembled. If all of the cases are identified, then a referent sample of controls may be assembled by random sampling of the study base. If all of the cases cannot be assembled, a hypothetical secondary base may need to be created. Preferably, only new-users of the drug should be included, and the risk-ratio will be different for acute users and chronic users. Studies will usually only be possible when researching the unintended effects of drugs. It is difficult to study efficacy because of confounding by indication. In occasional circumstances it may be possible to study efficacy (examples are given). Discussion of the dangers of designing with generalisability in mind is provided. Additionally, the similarities in study design between drug epidemiology and the RCT are discussed in detail, as well as the design-characteristics that cannot be shared between the two methods. (+info)
Text-based discovery in biomedicine: the architecture of the DAD-system.
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Current scientific research takes place in highly specialized contexts with poor communication between disciplines as a likely consequence. Knowledge from one discipline may be useful for the other without researchers knowing it. As scientific publications are a condensation of this knowledge, literature-based discovery tools may help the individual scientist to explore new useful domains. We report on the development of the DAD-system, a concept-based Natural Language Processing system for PubMed citations that provides the biomedical researcher such a tool. We describe the general architecture and illustrate its operation by a simulation of a well-known text-based discovery: The favorable effects of fish oil on patients suffering from Raynaud's disease [1]. (+info)
Prescribing patterns in patients using new antidepressants.
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AIMS: To study possible selective prescribing ('channelling') we compared characteristics of patients using the SSRI sertraline with patients using longer available SSRIs. METHODS: An observational cohort study in 1251 patients being prescribed an SSRI. RESULTS: In contrast to other studies, we found no evidence for channeling of sertraline. Sertraline was mainly prescribed for the labelled indication (depressive disorder), while older SSRIs were more often prescribed also for other indications. Time on the market was inversely associated to the proportion of patients treated for depressive disorder. CONCLUSIONS: We found no evidence for channeling of sertraline compared with prescribing patterns of older SSRIs. (+info)
Antipsychotic drugs and heart muscle disorder in international pharmacovigilance: data mining study.
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OBJECTIVES: To examine the relation between antipsychotic drugs and myocarditis and cardiomyopathy. DESIGN: Data mining using bayesian statistics implemented in a neural network architecture. SETTING: International database on adverse drug reactions run by the World Health Organization programme for international drug monitoring. MAIN OUTCOME MEASURES: Reports mentioning antipsychotic drugs, cardiomyopathy, or myocarditis. RESULTS: A strong signal existed for an association between clozapine and cardiomyopathy and myocarditis. An association was also seen with other antipsychotics as a group. The association was based on sufficient cases with adequate documentation and apparent lack of confounding to constitute a signal. Associations between myocarditis or cardiomyopathy and lithium, chlorpromazine, fluphenazine, haloperidol, and risperidone need further investigation. CONCLUSIONS: Some antipsychotic drugs seem to be linked to cardiomyopathy and myocarditis. The study shows the potential of bayesian neural networks in analysing data on drug safety. (+info)