Dataset Information

New use of prescription drugs prior to a cancer diagnosis.

ABSTRACT:

Purpose

Cancers often have considerable induction periods. This confers a risk of reverse causation bias in studies of cancer risk associated with drug use, as early symptoms of a yet undiagnosed cancer might lead to drug treatment in the period leading up to the diagnosis. This bias can be alleviated by disregarding exposure for some time before the cancer diagnosis (lag time). We aimed at assessing the duration of lag time needed to avoid reverse causation bias.

Methods

We identified all Danish patients with incident cancer between 2000 and 2012 (n?=?353?087). Incident use of prescription drugs was assessed prior to their cancer diagnosis as well as among population controls (n?=?1?402?400). Analyses were conducted for all cancers and for breast, lung, colon and prostate cancer individually. Further, analyses were performed for a composite measure of all incident drug use as well as for nine pre-specified individual drug classes, representing drug treatment likely to be prescribed for symptoms of the given cancers.

Results

The incidence rate for new drug treatment among cancer cases was stable around 130 per 1000 persons per month until 6?months prior to cancer diagnosis where it increased gradually and peaked at 434 in the month immediately preceding the cancer diagnosis. Considerable variation was observed among cancers, for example, breast cancer showed almost no such effect. The pre-selected drug classes showed a stronger increase prior to cancer diagnoses than drugs overall.

Conclusions

Incident use of drugs increases in the months prior to a cancer diagnosis. To avoid reverse causation, 6?months' lag time would be sufficient for most drug-cancer associations. © 2016 The Authors. Pharmacoepidemiology and Drug Safety published by John Wiley & Sons Ltd.

SUBMITTER: Pottegard A

PROVIDER: S-EPMC5299521 | biostudies-literature | 2017 Feb

REPOSITORIES: biostudies-literature

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Publications

New use of prescription drugs prior to a cancer diagnosis.

Pottegård Anton A Hallas Jesper J

Pharmacoepidemiology and drug safety 20161127 2

<h4>Purpose</h4>Cancers often have considerable induction periods. This confers a risk of reverse causation bias in studies of cancer risk associated with drug use, as early symptoms of a yet undiagnosed cancer might lead to drug treatment in the period leading up to the diagnosis. This bias can be alleviated by disregarding exposure for some time before the cancer diagnosis (lag time). We aimed at assessing the duration of lag time needed to avoid reverse causation bias.<h4>Methods</h4>We ident ...[more]

PMID: 27889931

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Project description:BACKGROUND: Patients routinely cite the media, after physicians and pharmacists, as a key source of information on new drugs, but there has been little research on the quality of drug information presented. We assessed newspaper descriptions of drug benefits and harms, the nature of the effects described and the presence or absence of other important information that can add context and balance to a report about a new drug. METHODS: We looked at newspaper coverage in the year 2000 of 5 prescription drugs launched in Canada between 1996 and 2001 that received a high degree of media attention: atorvastatin, celecoxib, donepezil, oseltamivir and raloxifene. We searched 24 of Canada's largest daily newspapers for articles reporting at least one benefit or harm of any of these 5 drugs. We recorded the benefits and harms reported and analyzed how such information was presented; we also determined whether clinical or surrogate outcomes were mentioned; if and how drug effects were quantified; whether contraindications, other treatment options and costs were mentioned; and whether any information on affiliations of quoted interviewees and potential conflicts of interest was presented. RESULTS: Our search yielded 193 articles reporting at least one benefit or harm for 1 of the 5 drugs. All of the articles mentioned at least one benefit, but 68% (132/193) made no mention of possible side effects or harms. Only 24% (120/510) of mentions of drug benefits and harms presented quantitative information. In 26% (31/120) of cases in which drug benefits and harms were quantified, the magnitude was presented only in relative terms, which can be misleading. Overall, 62% (119/193) of the articles gave no quantification of the benefits or harms. Thirty-seven (19%) of the 193 articles reported only surrogate benefits. Other information needed for informed drug-related decisions was often lacking: only 7 (4%) of the articles mentioned contraindications, 61 (32%) mentioned drug costs, 89 (46%) mentioned drug alternatives, and 30 (16%) mentioned nondrug treatment options (such as exercise or diet). Sixty-two percent (120/193) of the articles quoted at least one interviewee. After exclusion of industry and government spokespeople, for only 3% (5/164) of interviewees was there any mention of potential financial conflicts of interest. Twenty-six percent (15/57) of the articles discussing a study included information on study funding. INTERPRETATION: Our results raise concerns about the completeness and quality of media reporting about new medications.

Dataset Information

New use of prescription drugs prior to a cancer diagnosis.

Purpose

Methods

Results

Conclusions

Publications

New use of prescription drugs prior to a cancer diagnosis.

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