Publications by authors named "N McGauran"

26 Publications

  • Page 1 of 1

From publication bias to lost in information: why we need a central public portal for clinical trial data.

BMJ Evid Based Med 2020 Dec 10. Epub 2020 Dec 10.

Institute for Quality and Efficiency in Health Care, Köln, Germany.

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http://dx.doi.org/10.1136/bmjebm-2020-111566DOI Listing
December 2020

New drugs: where did we go wrong and what can we do better?

BMJ 2019 Jul 10;366:l4340. Epub 2019 Jul 10.

Institute for Quality and Efficiency in Health Care, Cologne, Germany.

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http://dx.doi.org/10.1136/bmj.l4340DOI Listing
July 2019

Guideline appraisal with AGREE II: online survey of the potential influence of AGREE II items on overall assessment of guideline quality and recommendation for use.

BMC Health Serv Res 2018 02 27;18(1):143. Epub 2018 Feb 27.

Medical Advisory Service of the German Social Health Insurance (MDS), Theodor-Althoff-Straße 47, 45133, Essen, Germany.

Background: The AGREE II instrument is the most commonly used guideline appraisal tool. It includes 23 appraisal criteria (items) organized within six domains. AGREE II also includes two overall assessments (overall guideline quality, recommendation for use). Our aim was to investigate how strongly the 23 AGREE II items influence the two overall assessments.

Methods: An online survey of authors of publications on guideline appraisals with AGREE II and guideline users from a German scientific network was conducted between 10th February 2015 and 30th March 2015. Participants were asked to rate the influence of the AGREE II items on a Likert scale (0 = no influence to 5 = very strong influence). The frequencies of responses and their dispersion were presented descriptively.

Results: Fifty-eight of the 376 persons contacted (15.4%) participated in the survey and the data of the 51 respondents with prior knowledge of AGREE II were analysed. Items 7-12 of Domain 3 (rigour of development) and both items of Domain 6 (editorial independence) had the strongest influence on the two overall assessments. In addition, Items 15-17 (clarity of presentation) had a strong influence on the recommendation for use. Great variations were shown for the other items. The main limitation of the survey is the low response rate.

Conclusions: In guideline appraisals using AGREE II, items representing rigour of guideline development and editorial independence seem to have the strongest influence on the two overall assessments. In order to ensure a transparent approach to reaching the overall assessments, we suggest the inclusion of a recommendation in the AGREE II user manual on how to consider item and domain scores. For instance, the manual could include an a-priori weighting of those items and domains that should have the strongest influence on the two overall assessments. The relevance of these assessments within AGREE II could thereby be further specified.
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http://dx.doi.org/10.1186/s12913-018-2954-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5828401PMC
February 2018

Secrecy or transparency? The future of regulatory trial data.

CMAJ 2017 02 14;189(5):E185-E186. Epub 2016 Nov 14.

Institute for Quality and Efficiency in Health Care, Cologne, Germany.

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http://dx.doi.org/10.1503/cmaj.161088DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5289868PMC
February 2017

Inconsistent conclusions on QoL outcomes from the same clinical trial.

Gastric Cancer 2016 Jan 18;19(1):318-9. Epub 2015 Apr 18.

Institute for Quality and Efficiency in Health Care (IQWiG), Im Mediapark 8, 50670, Cologne, Germany.

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http://dx.doi.org/10.1007/s10120-015-0499-7DOI Listing
January 2016

Information on new drugs at market entry: retrospective analysis of health technology assessment reports versus regulatory reports, journal publications, and registry reports.

BMJ 2015 Feb 26;350:h796. Epub 2015 Feb 26.

Institute for Quality and Efficiency in Health Care, Im Mediapark 8, 50670 Cologne, Germany

Background: When a new drug becomes available, patients and doctors require information on its benefits and harms. In 2011, Germany introduced the early benefit assessment of new drugs through the act on the reform of the market for medicinal products (AMNOG). At market entry, the pharmaceutical company responsible must submit a standardised dossier containing all available evidence of the drug's added benefit over an appropriate comparator treatment. The added benefit is mainly determined using patient relevant outcomes. The "dossier assessment" is generally performed by the Institute for Quality and Efficiency in Health Care (IQWiG) and then published online. It contains all relevant study information, including data from unpublished clinical study reports contained in the dossiers. The dossier assessment refers to the patient population for which the new drug is approved according to the summary of product characteristics. This patient population may comprise either the total populations investigated in the studies submitted to regulatory authorities in the drug approval process, or the specific subpopulations defined in the summary of product characteristics ("approved subpopulations").

Objective: To determine the information gain from AMNOG documents compared with non-AMNOG documents for methods and results of studies available at market entry of new drugs. AMNOG documents comprise dossier assessments done by IQWiG and publicly available modules of company dossiers; non-AMNOG documents comprise conventional, publicly available sources-that is, European public assessment reports, journal publications, and registry reports. The analysis focused on the approved patient populations.

Design: Retrospective analysis.

Data Sources: All dossier assessments conducted by IQWiG between 1 January 2011 and 28 February 2013 in which the dossiers contained suitable studies allowing for a full early benefit assessment. We also considered all European public assessment reports, journal publications, and registry reports referring to these studies and included in the dossiers.

Data Analysis: We assessed reporting quality for each study and each available document for eight methods and 11 results items (three baseline characteristics and eight patient relevant outcomes), and dichotomised them as "completely reported" or "incompletely reported (including items not reported at all)." For each document type we calculated the proportion of items with complete reporting for methods and results, for each item and overall, and compared the findings.Results 15 out of 27 dossiers were eligible for inclusion and contained 22 studies. The 15 dossier assessments contained 28 individual assessments of 15 total study populations and 13 approved subpopulations. European public assessment reports were available for all drugs. Journal publications were available for 14 out of 15 drugs and 21 out of 22 studies. A registry report in ClinicalTrials.gov was available for all drugs and studies; however, only 11 contained results. In the analysis of total study populations, the AMNOG documents reached the highest grade of completeness, with about 90% of methods and results items completely reported. In non-AMNOG documents, the rate was 75% for methods and 52% for results items; journal publications achieved the best rates, followed by European public assessment reports and registry reports. The analysis of approved subpopulations showed poorer complete reporting of results items, particularly in non-AMNOG documents (non-AMNOG versus AMNOG: 11% v 71% for overall results items and 5% v 70% for patient relevant outcomes). The main limitation of our analysis is the small sample size.

Conclusion: Conventional, publicly available sources provide insufficient information on new drugs, especially on patient relevant outcomes in approved subpopulations. This type of information is largely available in AMNOG documents, albeit only partly in English. The AMNOG approach could be used internationally to develop a comprehensive publication model for clinical studies and thus represents a key open access measure.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4353284PMC
http://dx.doi.org/10.1136/bmj.h796DOI Listing
February 2015

[Patient-relevant outcomes and surrogates in the early benefit assessment of drugs: first experiences].

Z Evid Fortbild Qual Gesundhwes 2014 11;108(8-9):528-38. Epub 2014 Aug 11.

Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen, Köln, Deutschland.

The Act on the Reform of the Market for Medicinal Products (AMNOG) became effective in Germany on January 1, 2011. Since then, the assessment of the added benefit of new drugs versus a therapeutic standard on the basis of dossiers submitted by pharmaceutical companies has been required by law. The Federal Joint Committee (G-BA) generally commissions the Institute for Quality and Efficiency in Health Care (IQWiG) with this task. The added benefit is primarily to be demonstrated on the basis of patient-relevant outcomes. The aim of this paper is to describe the feasibility of the early benefit assessment on the basis of patient-relevant outcomes by systematically characterising the outcomes available in company dossiers and comparing the companies' and IQWiG's evaluations regarding patient relevance and surrogate validity. Dossier assessments published between October 2011 and June 2012 were used for this purpose. The outcomes available and the respective evaluations were extracted and compared. 12 out of 22 submitted dossiers contained sufficient data to assess outcomes; all 12 assessable dossiers provided data on patient-relevant outcomes. Data on mortality and adverse events were available in all dossiers, except that one dossier did not contain adverse event data on the relevant subpopulation. In contrast, data on morbidity and health-related quality of life were available in 8 and 7 dossiers, respectively. Of a total of 214 outcomes extracted by IQWiG, 124 patient-relevant and 3 surrogate outcomes were included in IQWiG's assessment (companies: a total of 183 outcomes included, of which 172 were patient-relevant and 11 were surrogates). The first experiences with AMNOG have shown that in principle an early benefit assessment of drugs based on patient-relevant outcomes is feasible. The companies' and IQWiG's evaluations regarding patient relevance and surrogate validity of outcomes partly deviated from each other. By increasingly considering patient-relevant outcomes in approval studies, pharmaceutical companies can create the necessary data basis for the early benefit assessment.
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http://dx.doi.org/10.1016/j.zefq.2014.06.015DOI Listing
October 2015

Response to letter to the editor on "Early benefit assessment of new drugs in Germany--results from 2011 to 2012" [Health Policy 116(2-3) (2014) 147-153].

Health Policy 2014 Nov 23;118(2):272. Epub 2014 Oct 23.

Institute for Quality and Efficiency in Health Care, Im Mediapark 8, 50670 Cologne, Germany.

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http://dx.doi.org/10.1016/j.healthpol.2014.10.011DOI Listing
November 2014

New EMA policy-further measures needed to support comparative effectiveness assessments.

JAMA Intern Med 2014 Nov;174(11):1874-5

Institute for Quality and Efficiency in Health Care, Cologne, Germany.

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http://dx.doi.org/10.1001/jamainternmed.2013.7722DOI Listing
November 2014

Impact of inclusion of industry trial results registries as an information source for systematic reviews.

PLoS One 2014 17;9(4):e92067. Epub 2014 Apr 17.

Institute for Quality and Efficiency in Health Care, Cologne, Germany.

Background: Clinical trial results registries may contain relevant unpublished information. Our main aim was to investigate the potential impact of the inclusion of reports from industry results registries on systematic reviews (SRs).

Methods: We identified a sample of 150 eligible SRs in PubMed via backward selection. Eligible SRs investigated randomized controlled trials of drugs and included at least 2 bibliographic databases (original search date: 11/2009). We checked whether results registries of manufacturers and/or industry associations had also been searched. If not, we searched these registries for additional trials not considered in the SRs, as well as for additional data on trials already considered. We reanalysed the primary outcome and harm outcomes reported in the SRs and determined whether results had changed. A "change" was defined as either a new relevant result or a change in the statistical significance of an existing result. We performed a search update in 8/2013 and identified a sample of 20 eligible SRs to determine whether mandatory results registration from 9/2008 onwards in the public trial and results registry ClinicalTrials.gov had led to its inclusion as a standard information source in SRs, and whether the inclusion rate of industry results registries had changed.

Results: 133 of the 150 SRs (89%) in the original analysis did not search industry results registries. For 23 (17%) of these SRs we found 25 additional trials and additional data on 31 trials already included in the SRs. This additional information was found for more than twice as many SRs of drugs approved from 2000 as approved beforehand. The inclusion of the additional trials and data yielded changes in existing results or the addition of new results for 6 of the 23 SRs. Of the 20 SRs retrieved in the search update, 8 considered ClinicalTrials.gov or a meta-registry linking to ClinicalTrials.gov, and 1 considered an industry results registry.

Conclusion: The inclusion of industry and public results registries as an information source in SRs is still insufficient and may result in publication and outcome reporting bias. In addition to an essential search in ClinicalTrials.gov, authors of SRs should consider searching industry results registries.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0092067PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3990559PMC
January 2015

Early benefit assessment of new drugs in Germany - results from 2011 to 2012.

Health Policy 2014 Jun 8;116(2-3):147-53. Epub 2014 Jan 8.

Institute for Quality and Efficiency in Health Care, Im Mediapark 8, 50670 Cologne, Germany. Electronic address:

Rising drug costs in Germany led to the Act on the Reform of the Market for Medicinal Products (AMNOG) in January 2011. For new drugs, pharmaceutical companies have to submit dossiers containing all available evidence to demonstrate an added benefit versus an appropriate comparator therapy. The Federal Joint Committee (G-BA), the main decision-making body of the statutory healthcare system, is responsible for the overall procedure of "early benefit assessment". The Institute for Quality and Efficiency in Health Care (IQWiG) largely conducts the dossier assessments, which inform decisions by the G-BA on added benefit and support price negotiations. Of the 25 dossiers (excluding orphan drugs) assessed until 31 December 2012, 14 contained sufficient data from randomized active-controlled trials investigating patient-relevant outcomes or at least acceptable surrogates; 11 contained insufficient data. The most common indications were oncology (6) and viral infections (4). For the 14 drugs assessed, the extent of added benefit was rated as minor, considerable, and non-quantifiable in 3, 8, and 2 cases; the remaining drug showed no added benefit. Despite some shortcomings, for the first time it has been possible in Germany to implement a systematic procedure for assessing new drugs at market entry, thus providing support for price negotiations and informed decision-making for patients, clinicians and policy makers.
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http://dx.doi.org/10.1016/j.healthpol.2013.12.008DOI Listing
June 2014

Completeness of reporting of patient-relevant clinical trial outcomes: comparison of unpublished clinical study reports with publicly available data.

PLoS Med 2013 Oct 8;10(10):e1001526. Epub 2013 Oct 8.

Institute for Quality and Efficiency in Health Care, Cologne, Germany.

Background: Access to unpublished clinical study reports (CSRs) is currently being discussed as a means to allow unbiased evaluation of clinical research. The Institute for Quality and Efficiency in Health Care (IQWiG) routinely requests CSRs from manufacturers for its drug assessments. Our objective was to determine the information gain from CSRs compared to publicly available sources (journal publications and registry reports) for patient-relevant outcomes included in IQWiG health technology assessments (HTAs) of drugs.

Methods And Findings: We used a sample of 101 trials with full CSRs received for 16 HTAs of drugs completed by IQWiG between 15 January 2006 and 14 February 2011, and analyzed the CSRs and the publicly available sources of these trials. For each document type we assessed the completeness of information on all patient-relevant outcomes included in the HTAs (benefit outcomes, e.g., mortality, symptoms, and health-related quality of life; harm outcomes, e.g., adverse events). We dichotomized the outcomes as "completely reported" or "incompletely reported." For each document type, we calculated the proportion of outcomes with complete information per outcome category and overall. We analyzed 101 trials with CSRs; 86 had at least one publicly available source, 65 at least one journal publication, and 50 a registry report. The trials included 1,080 patient-relevant outcomes. The CSRs provided complete information on a considerably higher proportion of outcomes (86%) than the combined publicly available sources (39%). With the exception of health-related quality of life (57%), CSRs provided complete information on 78% to 100% of the various benefit outcomes (combined publicly available sources: 20% to 53%). CSRs also provided considerably more information on harms. The differences in completeness of information for patient-relevant outcomes between CSRs and journal publications or registry reports (or a combination of both) were statistically significant for all types of outcomes. The main limitation of our study is that our sample is not representative because only CSRs provided voluntarily by pharmaceutical companies upon request could be assessed. In addition, the sample covered only a limited number of therapeutic areas and was restricted to randomized controlled trials investigating drugs.

Conclusions: In contrast to CSRs, publicly available sources provide insufficient information on patient-relevant outcomes of clinical trials. CSRs should therefore be made publicly available. Please see later in the article for the Editors' Summary.
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http://dx.doi.org/10.1371/journal.pmed.1001526DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3793003PMC
October 2013

Access to regulatory data from the European Medicines Agency: the times they are a-changing.

Syst Rev 2012 Oct 30;1:50. Epub 2012 Oct 30.

Institute for Quality and Efficiency in Health Care, Im Mediapark 8 (KölnTurm), Cologne, 50670, Germany.

Systematic reviewers are increasingly trying to obtain regulatory clinical study reports (CSRs) to correct for publication bias. For instance, our organization, the Institute for Quality and Efficiency in Health Care, routinely asks drug manufacturers to provide full CSRs of studies considered in health technology assessments. However, since cooperation is voluntary, CSRs are available only for a subset of studies analysed. In the case of the inhaled insulin Exubera, the manufacturer refused to cooperate and in 2007 we asked the European Medicines Agency (EMA) to provide the relevant CSRs, but EMA denied access. Other researchers have reported similar experiences.In 2010 EMA introduced a new policy on access to regulatory documents, including CSRs, and has also undertaken further steps. The new policy has already borne fruit: in 2011, by providing additional sections of relevant CSRs, EMA made an important contribution to a review of oseltamivir (Tamiflu).Unfortunately, speedy implementation of the new policy may be endangered. We define a CSR following the International Conference on Harmonisation (ICH) E3 guideline. Although this guideline requires individual patient data listings, it does not necessarily require that these listings be made available in a computer-readable format, as proposed by some regulators from EMA and other agencies. However, access to raw data in a computer-readable format poses additional problems; merging this issue with that of access to CSRs could hamper the relatively simple implementation of the EMA policy. Moreover, EMA plans to release CSRs only on request; we suggest making these documents routinely available on the EMA website.Public access to regulatory data also carries potential risks. In our view, the issue of patient confidentiality has been largely resolved by current European legislation. The risk of other problems, such as conflicts of interest (CoIs) of independent researchers or quality issues can be reduced by transparency measures, such as the implementation of processes to evaluate CoIs and the publication of methods and protocols.In conclusion, regulatory data are an indispensable source for systematic reviews. Because of EMA's policy change, a milestone for data transparency in clinical research is within reach; let's hope it is not unnecessarily delayed.
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http://dx.doi.org/10.1186/2046-4053-1-50DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3495027PMC
October 2012

Impact of document type on reporting quality of clinical drug trials: a comparison of registry reports, clinical study reports, and journal publications.

BMJ 2012 Jan 3;344:d8141. Epub 2012 Jan 3.

Institute for Quality and Efficiency in Health Care, Dillenburger Strasse 27, 51105 Cologne, Germany.

Objective: To investigate to what extent three types of documents for reporting clinical trials provide sufficient information for trial evaluation.

Design: Retrospective analysis

Data Sources: Primary studies and corresponding documents (registry reports, clinical study reports, journal publications) from 16 health technology assessments of drugs conducted by the German Institute for Quality and Efficiency in Health Care between 2006 and February 2011. Data analysis We assessed reporting quality for each study and each available document for six items on methods and six on outcomes, and dichotomised them as "completely reported" or "incompletely reported." For each document type, we calculated the proportion of studies with complete reporting for methods and outcomes, per item and overall, and compared the findings.

Results: We identified 268 studies. Publications, study reports and registry reports were available for 192 (72%), 101 (38%), and 78 (29%) studies, respectively. Reporting quality was highest in study reports, which overall provided complete information for 90% of items (1086/1212). Registry reports provided more complete information on outcomes than on methods (overall 330/468 (71%) v 147/468 (31%)); the same applied to publications (594/1152 (52%) v 458/1152 (40%)). In the matched pairs analysis, reporting quality was poorer in registry reports than in study reports for overall methods and outcomes (P<0.001 in each case). Compared with publications, reporting quality was poorer in registry reports for overall methods (P<0.001), but better for outcomes (P=0.005).

Conclusion: Registry reports and publications insufficiently report clinical trials but may supplement each other. Measures to improve reporting include the mandatory worldwide implementation of adequate standards for results registration.
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http://dx.doi.org/10.1136/bmj.d8141DOI Listing
January 2012

Finding studies on reboxetine: a tale of hide and seek.

BMJ 2010 Oct 12;341:c4942. Epub 2010 Oct 12.

Institute for Quality and Efficiency in Health Care, Dillenburger Strasse 27, 51105 Cologne, Germany.

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http://dx.doi.org/10.1136/bmj.c4942DOI Listing
October 2010

Reporting a systematic review.

Chest 2010 May;137(5):1240-6

Department of Drug Assessment, Institute for Quality and Efficiency in Health Care, Dillenburger Str 27, 51105 Cologne, Germany.

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http://dx.doi.org/10.1378/chest.09-2625DOI Listing
May 2010

Reporting bias in medical research - a narrative review.

Trials 2010 Apr 13;11:37. Epub 2010 Apr 13.

Institute for Quality and Efficiency in Health Care, Dillenburger Str 27, 51105 Cologne, Germany.

Reporting bias represents a major problem in the assessment of health care interventions. Several prominent cases have been described in the literature, for example, in the reporting of trials of antidepressants, Class I anti-arrhythmic drugs, and selective COX-2 inhibitors. The aim of this narrative review is to gain an overview of reporting bias in the medical literature, focussing on publication bias and selective outcome reporting. We explore whether these types of bias have been shown in areas beyond the well-known cases noted above, in order to gain an impression of how widespread the problem is. For this purpose, we screened relevant articles on reporting bias that had previously been obtained by the German Institute for Quality and Efficiency in Health Care in the context of its health technology assessment reports and other research work, together with the reference lists of these articles.We identified reporting bias in 40 indications comprising around 50 different pharmacological, surgical (e.g. vacuum-assisted closure therapy), diagnostic (e.g. ultrasound), and preventive (e.g. cancer vaccines) interventions. Regarding pharmacological interventions, cases of reporting bias were, for example, identified in the treatment of the following conditions: depression, bipolar disorder, schizophrenia, anxiety disorder, attention-deficit hyperactivity disorder, Alzheimer's disease, pain, migraine, cardiovascular disease, gastric ulcers, irritable bowel syndrome, urinary incontinence, atopic dermatitis, diabetes mellitus type 2, hypercholesterolaemia, thyroid disorders, menopausal symptoms, various types of cancer (e.g. ovarian cancer and melanoma), various types of infections (e.g. HIV, influenza and Hepatitis B), and acute trauma. Many cases involved the withholding of study data by manufacturers and regulatory agencies or the active attempt by manufacturers to suppress publication. The ascertained effects of reporting bias included the overestimation of efficacy and the underestimation of safety risks of interventions.In conclusion, reporting bias is a widespread phenomenon in the medical literature. Mandatory prospective registration of trials and public access to study data via results databases need to be introduced on a worldwide scale. This will allow for an independent review of research data, help fulfil ethical obligations towards patients, and ensure a basis for fully-informed decision making in the health care system.
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http://dx.doi.org/10.1186/1745-6215-11-37DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2867979PMC
April 2010

Disagreement in primary study selection between systematic reviews on negative pressure wound therapy.

BMC Med Res Methodol 2008 Jun 26;8:41. Epub 2008 Jun 26.

Institute for Quality and Efficiency in Health Care (IQWiG), Dillenburger Str. 27, 51105 Cologne, Germany.

Background: Primary study selection between systematic reviews is inconsistent, and reviews on the same topic may reach different conclusions. Our main objective was to compare systematic reviews on negative pressure wound therapy (NPWT) regarding their agreement in primary study selection.

Methods: This retrospective analysis was conducted within the framework of a systematic review (a full review and a subsequent rapid report) on NPWT prepared by the Institute for Quality and Efficiency in Health Care (IQWiG). For the IQWiG review and rapid report, 4 bibliographic databases (MEDLINE, EMBASE, The Cochrane Library, and CINAHL) were searched to identify systematic reviews and primary studies on NPWT versus conventional wound therapy in patients with acute or chronic wounds. All databases were searched from inception to December 2006. For the present analysis, reviews on NPWT were classified as eligible systematic reviews if multiple sources were systematically searched and the search strategy was documented. To ensure comparability between reviews, only reviews published in or after December 2004 and only studies published before June 2004 were considered. Eligible reviews were compared in respect of the methodology applied and the selection of primary studies.

Results: A total of 5 systematic reviews (including the IQWiG review) and 16 primary studies were analysed. The reviews included between 4 and 13 primary studies published before June 2004. Two reviews considered only randomised controlled trials (RCTs). Three reviews considered both RCTs and non-RCTs. The overall agreement in study selection between reviews was 96% for RCTs (24 of 25 options) and 57% for non-RCTs (12 of 21 options). Due to considerable disagreement in the citation and selection of non-RCTs, we contacted the review authors for clarification (this was not initially planned); all authors or institutions responded. According to published information and the additional information provided, most differences between reviews arose from variations in inclusion criteria or inter-author study classification, as well as from different reporting styles (citation or non-citation) for excluded studies.

Conclusion: The citation and selection of primary studies differ between systematic reviews on NPWT, particularly with regard to non-RCTs. Uniform methodological and reporting standards need to be applied to ensure comparability between reviews as well as the validity of their conclusions.
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http://dx.doi.org/10.1186/1471-2288-8-41DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2496910PMC
June 2008

Negative pressure wound therapy: potential publication bias caused by lack of access to unpublished study results data.

BMC Med Res Methodol 2008 Feb 11;8. Epub 2008 Feb 11.

Institute for Quality and Efficiency in Health Care (IQWiG), Dillenburger Str, 27, 51105 Cologne, Germany.

Background: Negative pressure wound therapy (NPWT) is widely applied, although the evidence base is weak. Previous reviews on medical interventions have shown that conclusions based on published data alone may no longer hold after consideration of unpublished data. The main objective of this study was to identify unpublished randomised controlled trials (RCTs) on NPWT within the framework of a systematic review.

Methods: RCTs comparing NPWT with conventional wound therapy were identified using MEDLINE, EMBASE, CINAHL and The Cochrane Library. Every database was searched from inception to May 2005. The search was updated in December 2006. Reference lists of original articles and systematic reviews, as well as congress proceedings and online trial registers, were screened for clues to unpublished RCTs. Manufacturers of NPWT devices and authors of conference abstracts were contacted and asked to provide study information. Trials were considered nonrandomised if concealment of allocation to treatment groups was classified as "inadequate". The study status was classified as "completed", "discontinued", "ongoing" or "unclear". The publication status of completed or discontinued RCTs was classified as "published" if a full-text paper on final study results (completed trials) or interim results (discontinued trials) was available, and "unpublished" if this was not the case. The type of sponsorship was also noted for all trials.

Results: A total of 28 RCTs referring to at least 2755 planned or analysed patients met the inclusion criteria: 13 RCTs had been completed, 6 had been discontinued, 6 were ongoing, and the status of 3 RCTs was unclear. Full-text papers were available on 30% of patients in the 19 completed or discontinued RCTs (495 analysed patients in 10 published RCTs vs. 1154 planned patients in 9 unpublished RCTs). Most information about conference abstracts and unpublished study information referring to trials that were unpublished at the time these documents were generated was obtained from the manufacturer Kinetic Concepts Inc. (KCI) (19 RCTs), followed by The Cochrane Library (18) and a systematic review (15). We were able to obtain some information on the methods of unpublished RCTs, but results data were either not available or requests for results data were not answered; the results of unpublished RCTs could therefore not be considered in the review. One manufacturer, KCI, sponsored the majority of RCTs (19/28; 68%). The sponsorship of the remaining trials was unclear.

Conclusion: Multi-source comprehensive searches identify unpublished RCTs. However, lack of access to unpublished study results data raises doubts about the completeness of the evidence base on NPWT.
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http://dx.doi.org/10.1186/1471-2288-8-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2291064PMC
February 2008

Have ALLHAT, ANBP2, ASCOT-BPLA, and so forth improved our knowledge about better hypertension care?

Hypertension 2006 Jul 30;48(1):1-7. Epub 2006 May 30.

Institute for Quality and Efficiency in Health Care, Cologne, Germany.

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http://dx.doi.org/10.1161/01.HYP.0000226145.49783.a9DOI Listing
July 2006

The psychological effects of exposure to mixed organic solvents on car painters.

Disabil Rehabil 2002 Jun;24(9):455-61

Institute of Occupational Medicine and Hygiene, Otto-von-Guericke University of Magdeburg, Germany.

Purpose: Interest in diseases of the nervous system resulting from occupational exposure to mixed organic solvents has greatly increased. The aim of our study was to identify preclinical effects of low-level chronic solvent exposure on the central nervous system in car painters by assessing their cognitive performance.

Methods: This psychological study involved 169 clinically healthy male volunteers (84 car painters and 85 controls) and is part of a comprehensive study investigating effects of solvent exposure. The test battery included paper-pencil tests (vocabulary test, block design test, c.i., d2 test), computer-based tests (digit span test, simple-choice reaction time test), and a questionnaire to assess the participants' mental state.

Results: Car painters with long-term exposure to solvents showed psychological deviations such as deficits in concentration, memory and reaction time compared to unexposed subjects. The significant differences between the two groups were confirmed by multivariate statistical analysis.

Conclusions: Our study displayed psychological effects associated with long-term solvent exposure in concentrations below German threshold limit values. These findings emphasize the necessity to promote the resolute compliance with occupational safety and health regulations in affected companies.
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http://dx.doi.org/10.1080/09638280110102126DOI Listing
June 2002

[Subjective need for help and objectified geriatric assess. Comparison of the Halberstädter Gerontologic Study and the Augsburger Senior Study].

Z Gerontol Geriatr 2002 Feb;35(1):60-9

Institut für Sozialmedizin, Universität Magdeburg Leipzigerstr. 44, 39120 Magdeburg, Germany.

The Halberstadt Geriatric Study and the Augsburg Senior Citizens Study contain common elements of geriatric assessment (self-assessment of functional dependence, objective evaluation of the functional status). In our cross-sectional investigation, the objective was to examine associations between functional dependence and functional tests and to investigate whether association patterns differed between the surveyed groups. The prospective Halberstadt study began in the German Democratic Republic in 1983 within the framework of a vocational examination before employees entered retirement. In 1995 the study was reactivated; 367 survivors answered a postal questionnaire of which 167 persons took part in a test battery including performance and psychometric tests. The 214 Augsburg test persons had already taken part in the MONICA survey (monitoring of trends and determinants of cardiovascular disease). In 1997 they were assessed in a follow-up study, the aim being to determine the functional status of an elderly cohort through interviews and functional tests. In both studies functional dependence was defined by the (I)ADL concept [(instrumental) activities of daily living]. The participants' functional status was determined with the help of performance tests such as foot tapping and cognitive tests such as the Mini-Mental State Examination. Additionally, medical diagnoses and the use of medical facilities were investigated. The presence of functional dependence was consistently and predominantly significantly associated with the functional status assessed by performance tests. These results were largely confirmed by a logistic regression model. Our results show that even in populations with a different socialization, performance tests are stable indicators of functional dependence and should therefore be incorporated in geriatric assessment programs. The introduction of a standardized assessment program with subsequent intervention measures could lead to a delay of functional dependence and need of care and reduce costs in the health care system.
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http://dx.doi.org/10.1007/s003910200009DOI Listing
February 2002

Assessing the suitability of cross-sectional and longitudinal cardiac rhythm tests with regard to identifying effects of occupational chronic lead exposure.

J Occup Environ Med 2002 Jan;44(1):59-65

Institute of Occupational Medicine and Hygiene, Otto-von-Guericke University of Magdeburg, Leipziger Str. 44, 39120 Magdeburg, Germany.

The aim of this study was to examine whether signs of neurotoxic influence on the autonomic nervous system, after lengthy occupational lead exposure, could be revealed by appropriate cardiac rhythm analysis. A total of 109 male lead-exposed workers and 27 controls were examined in a cross-sectional study. In addition, 17 lead-exposed participants were investigated a second time in a follow-up study 4 years later. Heart rate variability was assessed in rest, strain, and recovery phases. In the cross-sectional study, lead-exposed persons showed a delayed restoration of cardiac rhythm parameters to the initial vegetative state after the strain phase. This effect significantly increased over a period of 4 more years of exposure in the 17 workers participating in the follow-up study. We found vagal depression caused by long-term lead exposure within the current threshold limit value range, which can be interpreted as an adverse effect.
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http://dx.doi.org/10.1097/00043764-200201000-00010DOI Listing
January 2002

Workplace conditions predict the risk of premature death and functional dependence after retirement--results of a gerontological follow-up study in Germany.

Public Health 2001 Sep;115(5):345-9

Institut für Sozialmedizin, Universitätsklinikum, Magdeburg, Germany.

Between 1983 and 1985, 595 employees who were entering retirement in East Germany were given a medical examination and asked to assess their workplace conditions. Ten years later, we examined whether occupational predictors were associated with death and functional dependence among the study participants and assessed how the surviving pensioners coped with activities and instrumental activities of daily living. We assigned the occupational factors reported between 1983 and 1985 to two scales: demands and resources. Multiple logistic regression analyses were carried out to examine the association of occupational and medical predictors with the outcome variables death and functional dependence. Workplace resources but not demands were significantly associated with a reduced chance of death in women, independent of medical diagnoses. For men neither of these associations were verified. Concerning functional dependence individual items such as 'control over work content' (for both sexes) significantly reduced the risk of developing ADL-dependence. The associations remained stable after medical diagnoses were additionally taken into consideration. The results of our study highlight the influence of occupational factors beyond working life and support the importance of starting geriatric health promotion before retirement age.
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http://dx.doi.org/10.1038/sj/ph/1900787DOI Listing
September 2001