KEY ISSUES FOR LITERATURE SEARCHING

Transcription

1 Session 2, HTAi workshop June 25th 2011, Rio de Janeiro 2011 KEY ISSUES FOR LITERATURE SEARCHING TO SUPPORT HTA Ingrid Harboe, Research Librarian

2 Key issues for literature searching to support HTA Factors which impact on the search approach Components of the HTA informed by exhaustive searching e.g. reviews of effect and economic evaluations Components of the HTA informed by pragmatic searching e.g. economic models Resources which do we need to search? Bibliographic databases, study types, routine data, registers, registries August 30,

3 Identifying research evidence The medical literature can be compared to a jungle. It is fast growing, full of dead wood, sprinkled with treasures and infested with spiders and snakes. Peter Morgan, scientific editor, Canadian Medical Association. "Macaws in deep jungle, Amazon, Brazil Harry Holcroft, barroyo.wordpress.com August 30,

4 A well conducted literature search is important in order to identify as much relevant research as possible that has been carried out on a particular question. sensitivity precision August 30,

5 Factors which impact on the search approach The main purpose of a literature search is to inform the HTA with as much relevant high quality research evidence as possible available to a specific question. To identify the research evidence we need to clarify: The type of research question Effects of intervention, Diagnosis, Prognosis, Aetiology, Experiences, The components of the HTA to be informed Effects evidence, adverse effects, cost-effectiveness, utility and /or quality of life, ethical issues, etc. Which study design is appropriate to search for? e.g. Systematic reviews, randomised controlled trials, controlled trials, cohort studies etc. Type of product and time frame e.g. Traditional HTA report or Rapid review Which databases/ resources to search (Cochrane Handbook 2009) 5

6 Why is it essential to do an exhaustive search? To reduce potential effects of publication bias To identify a larger number of high quality studies to improve sample size To demonstrate to readers that our methods have been unbiased, transparent and replicable: By describing how we searched and where we searched To show that as many potentially relevant studies as possible have been considered By explaining clearly why studies have been excluded from a review To allow readers to assess how much evidence we may have missed August 30,

7 Why is it essential to do an exhaustive search? - continued To identify high quality studies we need to search different databases Which study design is it appropriate to search for depends on the type of research question Research into identifying studies that are not RCTs or are in areas that are not limited to effectiveness, currently shows that wide searching is required to ensure thorough retrieval, for example: Diagnostic test studies (Glanville 2011) Adverse effects information (Golder 2010)

8 Where does bias come from? Much research is never formally published Not all research is published in journals Not all research published in journals is indexed on major databases Not all research that we know is indexed on databases can be easily retrieved by the specific search strategy we develop: research is not always described in the same way by authors research can often be poorly reported research is not always indexed in databases consistently, or in the way that we would find most useful other reasons...? August 30,

9 Question Study design Clinical Queries Prevalence Cross-sectional study - Etiology Diagnosis Effect of interventions 1. Cohort study 2. Case-control study Cross-sectional study (with a gold standard) Randomized controlled trial Etiology Diagnosis Therapy/Treatment Prognosis Cohort study Prognosis Experiences/ attitudes Qualitative study Qualitative (Ormstad 2011)

10 The components of the HTA and how to inform them Essential components e.g. in a question about effects of intervention could be Effects evidence Adverse effects Cost-effectiveness Utility an/or quality of life Ethical issues, etc. Example of a research question:...to evaluate the relative efficacy, safety and cost-effectiveness of Nicotine replacement therapy (NRT), bupropion and varenicline in order to inform the development of a new Norwegian treatment guideline for smoking cessation in primary care August 30,

11 Components of the HTA informed by exhaustive searching To answer this question we need to: Structure and break down the question: 1. The efficacy and safety of nicotine replacement therapy compared to varenicline and bupropion for smoking cessation 2. The cost- effectiveness of nicotine replacement therapy compared to varenicline and bupropion for smoking cessation Use the PICO format to identify Population: smoking Intervention: nicotine replacement therapy Comparator: varenicline or bupropion Outcome: smoking cessation Decide which study designs to search for e.g. Systematic reviews, randomised controlled trials, controlled trials, cohort studies etc. Decide which databases to search for August 30,

12 Components of the HTA informed by exhaustive searching - continued To answer the question we need to: Decide whether to search specific resources to inform the other components : Adverse effects Cost-effectiveness, utility/ quality of life Ethical issues etc Decide whether to search for ongoing research Will new studies be published soon? Decide whether to search for routine data and other data for models Epidemiological data: incidence and prevalence Outcome data Quality of life data patient reported outcomes Costs Resource use Adverse effects August 30,

13 Sensitive searching for smoking cessation 1 Smoking / 2 smoker* or smoking.ti,ab. 3 tobacco or cigarette*.ti,ab 4 or/1-3 Population: Smoking 5 Amfebutamone/ 6 (amfebutamone or bupropion).ti,ab. 7 (cyban or zyban).ti,ab. 8 Varenicline/ 9 varenicline.ti,ab. 10 (champix or chantix).ti,ab. 11 or/ and Nicotine gum/ 14 (nicotine adj2 gum?).ti,ab. 15 (nicotinel* or nicoret*).ti,ab. 16 Nicotine patch/ 17 (nicotine adj2 patch*).ti,ab. 18 Lozenge/ 19 (nicotine adj2 (lozenge? or tablet?)).ti,ab. 20 Nose Spray/ 21 (nicotine adj2 spray?).ti,ab. 22 Nicotine/ 23 (nicotine adj2 inhaler?).ti,ab. 24 or/ and 24 Intervention (comparator): Synonyms for Drugs (Comment: Search nr. 5: in EMBASE Amfebutamone is Subject Heading for Bupropion) Intervention: Synonyms for Nicotine Replacement Truncation? = optional adding one character * = optional adding any suffix (ending) of word August 30,

14 Systematic literature searches were performed in: To identify Systematic Reviews and HTAs: EMBASE & Ovid MEDLINE Cochrane Library; CDSR, DARE, HTA, NHS EED Centre for Reviews and Dissemination; DARE, HTA,NHS EED To identify Randomised Controlled Trials and Health Economic Evaluations: EMBASE & Ovid MEDLINE (using search filter) Cochrane Library; CENTRAL and NHS EED Centre for Reviews and Dissemination; HTA,NHS EED August 30,

15 Components of the HTA informed by more pragmatic searching Pragmatic searching is not as detailed and broad as exhaustive searching Pragmatic searching might be useful to find e.g.: Epidemiological data: incidence and prevalence e.g. Epidemiological information about a specific country on smoking rates or smoking related mortality Data for economic models Quality of life data and patient reported outcomes Unit costs e.g. National costs data, local costs Resource use e.g. Registry data Adverse effects (Glanville 2011) August 30,

16 Resources to search (examples) Systems Summaries (Clin. guidel., ref. books) 1. Future patient journals 2. Best Practice, UpToDate, Clinical Evidence, Clinical guidelines, G-I-N DiCenso A, 2009 Synopses of syntheses Syntheses (Systematic reviews/ HTA reports) Synopses of single studies (Evidence-based abstract, journals) Single studies 3. Cochrane Library: Other Reviews (DARE), Evidence-based journals 4. Cohrane Database of Systematic Reviews, Health Technology Assessment Database (HTA), PEDro, OTseeker 5. Evidence-based abstraction journals 6. Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE/ PubMed, EMBASE, NHS Economic Evaluation Database August 30,

17 Summing up key issues for literature searching The main purpose is to inform the HTA with the relevant high quality research evidence available to a specific question The search approach will vary according to the research question To identify the research evidence we need to consider: Is the question about: Effects of intervention, Diagnosis, Prognosis, Aetiology, Experiences The purpose and time frame regarding the project Which components we need to inform by exhaustive searching e.g. reviews of effect and economic evaluations Which components we need to inform by more pragmatic searching e.g. economic models Which resources we need to search? Bibliographic databases, study types, routine data, registers etc August 30,

18 References Cochrane Handbook for Systematic Reviews of Interventions Version [updated March 2011] Glanville, J. Generating data (systematic reviews and meta-analyses). PPT presentation, York Health Economics Consortium Golder S, Loke YK. Sources of information on adverse effects: a systematic review. Health Information and Libraries Journal 2010;Sep;27(3): Hopewell S, Clarke M, Askie L. Reporting of trials presented in conference abstracts needs to be improved. Journal of Clinical Epidemiology 2006;59: Hopewell S, Eisinga A, Clarke M. Better reporting of randomized trials in biomedical journal and conference abstracts. Journal of Information Science 2007; doi: / Hopewell S, McDonald S, Clarke M, Egger M. Grey literature in metaanalyses of randomized trials of health care interventions. Cochrane Database of Systematic Reviews, Art. No.: MR doi: / MR pub3. Available: Accessed 1 May 2007 Ormstad S. How to develop search strategies. PPT presentation, Norwegian Knowledge Centre for the Health Services 2011 Royle P, Waugh N. Literature searching for clinical and cost-effectiveness studies used in health technology assessment reports carried out for the National Institute for Clinical Excellence appraisal system. Health Technology Assessment 2003;7(34). August 30,

19 Thank you - Obrigada