Pharmacoepidemiology in practice. Current status and future trends

Understanding and Avoiding Immortal-Time Bias in Gastrointestinal Observational Research

Pharmacoepidemiologic analyses, in which observational data is interrogated to evaluate relationships between patterns of drug use and both beneficial and adverse outcomes, are being increasingly used in the study of inflammatory bowel disease. However, the results of many of these analyses may be corrupted by the presence of immortal person-time bias, an analytic error which can result in an overestimation of the benefits of medical therapy. In this report, we will describe immortal person-time bias, explain the mechanism through which it confers a false benefit, and guide the reader in how to identify this source of bias in the medical literature.

Veterinary pharmacovigilance. Part 2. Veterinary pharmacovigilance in practice -- the operation of a spontaneous reporting scheme in a European Union country -- the UK, and schemes in other countries

Veterinary pharmacovigilance, as it operates in the European Union (EU), covers a very broad remit, including adverse effects in treated animals, exposed humans and the environment, and in addition, it extends to cover the violation of maximum residue limits. The mainstay of veterinary pharmacovigilance is the spontaneous reporting scheme working along side other systems such as those reporting on residues surveillance. One of the most well established schemes in the EU is that operating in the UK and this paper examines the evolution of that scheme and some of its findings, data from other countries, and information available from the literature. It also tentatively examines the ways that pharmacovigilance can be used for regulatory purposes, and the contribution from pharmacoepidemiology.

Exploring the context of drug use: a problem-based learning course in pharmacoepidemiology for undergraduate science students

The teaching of pharmacoepidemiology has been largely confined to health care professionals and graduate students. This paper reports an attempt to use problem-based learning (PBL) to teach the elements of that discipline to undergraduate science students. Carefully sequenced problems led students to consider the following issues: the terms used in epidemiology, merits and demerits of different epidemiological study designs, pharmacovigilance, the nature of evidence in law and science, economic evaluation of drugs and the use of drugs in different cultures. The 12-week course was taken by students in their final term prior to graduation. Multiple evaluation procedures were used: specific forms for assessing tutorial participation, individual explorations assessed usually by written essays and problem-solving exercises. The course has received high ratings from the students. The observations over a 10-year period suggest that PBL is a feasible approach to teach the social dimensions of drug use.

Presence of pharmacoepidemiology in three bibliographic databases: Medline, IPA and SCI

OBJECTIVE

The objective of this study is to make a comparative description of the evolution and distribution of international research into pharmacoepidemiology, using three bibliographic databases, in order to select the most appropriate for future bibliometric studies.

METHODS

Bibliographic searches were performed using the following databases: Medline (1966-99), IPA (1970-99) and SCI (1990-99), using the term 'pharmacoepidemiology'. On the basis of these searches, the number of original articles per year and per journal title were noted. The growth of the output of scientific writing was found to fit Price's law.

RESULTS

A total of 845 original articles were recovered: 467 from IPA, 219 from Medline and 159 from SCI. The highest mean number of original articles per year (33.4) was obtained with the IPA database. Price's exponential growth pattern was observed among all three databases. The total numbers of journals in which the original articles were published were 102 in Medline, 65 in IPA and 60 in SCI. The journals providing a single original article comprised 65% of the Medline titles and 61% of those in IPA and SCI.

CONCLUSIONS

International research into pharmacoepidemiology presents an exponential growth pattern, in accordance with Price's law. There is a large degree of publishing dispersion. IPA was found to be the bibliographic database that recovered the greatest number of original articles, nearly half of which were published in Pharmacoepidemiology and Drug Safety. We therefore consider the latter database appropriate for bibliometric studies in the field of pharmacoepidemiology.

Damage in systemic lupus erythematosus and its association with corticosteroids

OBJECTIVE

To evaluate the association between corticosteroid use and organ damage in patients with systemic lupus erythematosus (SLE).

METHODS

The occurrence and date of organ damage, as measured by the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index, were determined for 539 patients enrolled in the Hopkins Lupus Cohort Study. The risk of damage associated with the cumulative prednisone dose, high-dose prednisone (> or =60 mg/day for > or =2 months), and pulse methylprednisolone (1,000 mg intravenously for 1-3 days) was estimated using Cox proportional hazards regression analyses, controlling for age, race, and sex. Risk estimates for the cumulative prednisone dose were based on a reference dose of 36.5 gm (e.g., 10 mg of prednisone daily for 10 years [or equivalent]).

RESULTS

The cumulative prednisone dose was significantly associated with the development of osteoporotic fractures (relative risk [RR] 2.5, 95% confidence interval [95% CI] 1.7, 3.7), symptomatic coronary artery disease (RR 1.7, 95% CI 1.1, 2.5), and cataracts (RR 1.9, 95% CI 1.4, 2.5). Each intravenous pulse was associated with a small increase in the risk of osteoporotic fractures (RR 1.3, 95% CI 1.0, 1.8); however, this result failed to reach statistical significance (P = 0.07). Each 2-month exposure to high-dose prednisone was associated with a 1.2-fold increase in the risk of both avascular necrosis (95% CI 1.1, 1.4) and stroke (95% CI 1.0, 1.5).

CONCLUSION

SLE patients receiving long-term prednisone therapy were at significant risk of morbidity due to permanent organ damage. Additional research is required to determine the relative contributions of SLE disease activity and corticosteroids to the pathogenesis of specific types of organ damage. Furthermore, new steroid-sparing therapies are needed in order to treat disease activity and minimize cumulative and high-dose prednisone exposure.