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Kim TH, Kang JW, Lee MS. When conducting a systematic review, can one trade search efficiency for potential publication bias? Res Synth Methods 2022; 13:662-663. [PMID: 35948520 DOI: 10.1002/jrsm.1596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 07/18/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Tae-Hun Kim
- Korean Medicine Clinical Trial Center, Korean Medicine Hospital, Kyung Hee University, Seoul, South Korea
| | - Jung Won Kang
- Department of Acupuncture & Moxibustion, College of Korean Medicine, Kyung Hee University, Seoul, South Korea
| | - Myeong Soo Lee
- Division of Clinical Medicine, Korea Institute of Oriental Medicine, Daejeon, Republic of Korea
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Lee S, Jo DH, Kim KH. Acupuncture for treating whiplash-associated disorder: A systematic review and meta-analysis protocol. Medicine (Baltimore) 2018; 97:e12654. [PMID: 30313054 PMCID: PMC6203494 DOI: 10.1097/md.0000000000012654] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND This review aims to evaluate the effectiveness and safety of acupuncture treatment for patients with whiplash-associated disorder (WAD). METHODS We will search the following databases from their inception to October 2018: MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, the Cumulative Index to Nursing and Allied Health Literature, the Allied and Complementary Medicine Database, 1 Chinese database (China National Knowledge Infrastructure), 1 Japanese database (Japan Science and Technology Information Aggregator, Electronic), and 5 Korean databases (KoreaMed, Research Information Service System, Korean Studies Information Service System, Database Periodical Information Academic, and Oriental Medicine Advanced Searching Integrated System). All randomized controlled trials of acupuncture for WAD will be considered for inclusion without language restrictions. The risk of bias will be assessed using the Cochrane risk of bias tool. The mean difference or standard mean difference for continuous data and risk ratio for dichotomous data will be calculated with 95% confidence intervals. DISSEMINATION The results of this review will be disseminated through peer-reviewed journal articles or conference presentations, and may provide important guidance for clinicians and patients regarding the use of acupuncture treatment for treating WAD. TRIAL REGISTRATION NUMBER PROSPERO 2018: CRD42018106964.
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Affiliation(s)
| | - Dae-Hyun Jo
- Department of Acupuncture & Moxibustion Medicine, Graduate School, Kyung Hee University, Seoul
| | - Kun Hyung Kim
- Department of Acupuncture & Moxibustion, School of Korean Medicine, Pusan National University, Yangsan, South Korea
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Mortier P, Cuijpers P, Kiekens G, Auerbach RP, Demyttenaere K, Green JG, Kessler RC, Nock MK, Bruffaerts R. The prevalence of suicidal thoughts and behaviours among college students: a meta-analysis. Psychol Med 2018; 48:554-565. [PMID: 28805169 DOI: 10.1017/s0033291717002215] [Citation(s) in RCA: 240] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BACKGROUND Adolescence and young adulthood carry risk for suicidal thoughts and behaviours (STB). An increasing subpopulation of young people consists of college students. STB prevalence estimates among college students vary widely, precluding a validated point of reference. In addition, little is known on predictors for between-study heterogeneity in STB prevalence. METHODS A systematic literature search identified 36 college student samples that were assessed for STB outcomes, representing a total of 634 662 students [median sample size = 2082 (IQR 353-5200); median response rate = 74% (IQR 37-89%)]. We used random-effects meta-analyses to obtain pooled STB prevalence estimates, and multivariate meta-regression models to identify predictors of between-study heterogeneity. RESULTS Pooled prevalence estimates of lifetime suicidal ideation, plans, and attempts were 22.3% [95% confidence interval (CI) 19.5-25.3%], 6.1% (95% CI 4.8-7.7%), and 3.2% (95% CI 2.2-4.5%), respectively. For 12-month prevalence, this was 10.6% (95% CI 9.1-12.3%), 3.0% (95% CI 2.1-4.0%), and 1.2% (95% CI 0.8-1.6%), respectively. Measures of heterogeneity were high for all outcomes (I 2 = 93.2-99.9%), indicating substantial between-study heterogeneity not due to sampling error. Pooled estimates were generally higher for females, as compared with males (risk ratios in the range 1.12-1.67). Higher STB estimates were also found in samples with lower response rates, when using broad definitions of suicidality, and in samples from Asia. CONCLUSIONS Based on the currently available evidence, STB seem to be common among college students. Future studies should: (1) incorporate refusal conversion strategies to obtain adequate response rates, and (2) use more fine-grained measures to assess suicidal ideation.
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Affiliation(s)
- P Mortier
- Research Group Psychiatry,Department of Neurosciences,KU Leuven University,Leuven,Belgium
| | - P Cuijpers
- Department of Clinical,Neuro and Developmental Psychology,Vrije Universiteit Amsterdam,the Netherlands
| | - G Kiekens
- Research Group Psychiatry,Department of Neurosciences,KU Leuven University,Leuven,Belgium
| | - R P Auerbach
- Department of Psychiatry,Harvard Medical School,Boston,MA,USA
| | - K Demyttenaere
- Research Group Psychiatry,Department of Neurosciences,KU Leuven University,Leuven,Belgium
| | - J G Green
- School of Education,Boston University,Boston,MA,USA
| | - R C Kessler
- Department of Health Care Policy,Harvard Medical School,Harvard University,Boston,MA,USA
| | - M K Nock
- Department of Psychology,Harvard University,Cambridge,MA,USA
| | - R Bruffaerts
- Research Group Psychiatry,Department of Neurosciences,KU Leuven University,Leuven,Belgium
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Lee A, Chan SKC, Fan LTY. Stimulation of the wrist acupuncture point PC6 for preventing postoperative nausea and vomiting. Cochrane Database Syst Rev 2015; 2015:CD003281. [PMID: 26522652 PMCID: PMC4679372 DOI: 10.1002/14651858.cd003281.pub4] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Postoperative nausea and vomiting (PONV) are common complications following surgery and anaesthesia. Antiemetic drugs are only partially effective in preventing PONV. An alternative approach is to stimulate the PC6 acupoint on the wrist. This is an update of a Cochrane review first published in 2004, updated in 2009 and now in 2015. OBJECTIVES To determine the effectiveness and safety of PC6 acupoint stimulation with or without antiemetic drug versus sham or antiemetic drug for the prevention of PONV in people undergoing surgery. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library, Issue 12, 2014), MEDLINE (January 2008 to December 2014), EMBASE (January 2008 to December 2014), ISI Web of Science (January 2008 to December 2014), World Health Organization Clinical Trials Registry, ClinicalTrials.gov, and reference lists of articles to identify additional studies. We applied no language restrictions. SELECTION CRITERIA All randomized trials of techniques that stimulated the PC6 acupoint compared with sham treatment or drug therapy, or combined PC6 acupoint and drug therapy compared to drug therapy, for the prevention of PONV. Interventions used in these trials included acupuncture, electro-acupuncture, transcutaneous electrical acupoint stimulation, transcutaneous nerve stimulation, laser stimulation, capsicum plaster, acu-stimulation device, and acupressure in people undergoing surgery. Primary outcomes were the incidences of nausea and vomiting after surgery. Secondary outcomes were the need for rescue antiemetic therapy and adverse effects. DATA COLLECTION AND ANALYSIS Two review authors independently extracted the data and assessed the risk of bias domains for each trial. We used a random-effects model and reported risk ratio (RR) with associated 95% confidence interval (95% CI). We used trial sequential analyses to help provide information on when we had reached firm evidence in cumulative meta-analyses of the primary outcomes, based on a 30% risk ratio reduction in PONV. MAIN RESULTS We included 59 trials involving 7667 participants. We rated two trials at low risk of bias in all domains (selection, attrition, reporting, blinding and other). We rated 25 trials at high risk in one or more risk-of-bias domains. Compared with sham treatment, PC6 acupoint stimulation significantly reduced the incidence of nausea (RR 0.68, 95% CI 0.60 to 0.77; 40 trials, 4742 participants), vomiting (RR 0.60, 95% CI 0.51 to 0.71; 45 trials, 5147 participants) and the need for rescue antiemetics (RR 0.64, 95% CI 0.55 to 0.73; 39 trials, 4622 participants). As heterogeneity among trials was substantial and there were study limitations, we rated the quality of evidence as low. Using trial sequential analysis, the required information size and boundary for benefit were reached for both primary outcomes.PC6 acupoint stimulation was compared with six different types of antiemetic drugs (metoclopramide, cyclizine, prochlorperazine, droperidol. ondansetron and dexamethasone). There was no difference between PC6 acupoint stimulation and antiemetic drugs in the incidence of nausea (RR 0.91, 95% CI 0.75 to 1.10; 14 trials, 1332 participants), vomiting (RR 0.93, 95% CI 0.74 to 1.17; 19 trials, 1708 participants), or the need for rescue antiemetics (RR 0.87, 95% CI 0.65 to 1.16; 9 trials, 895 participants). We rated the quality of evidence as moderate, due to the study limitations. Using trial sequential analyses, the futility boundary was crossed before the required information size was surpassed for both primary outcomes.Compared to antiemetic drugs, the combination of PC6 acupoint stimulation and antiemetic therapy reduced the incidence of vomiting (RR 0.56, 95% CI 0.35 to 0.91; 9 trials, 687 participants) but not nausea (RR 0.79, 95% CI 0.55 to 1.13; 8 trials, 642 participants). We rated the quality of evidence as very low, due to substantial heterogeneity among trials, study limitations and imprecision. Using trial sequential analysis, none of the boundaries for benefit, harm or futility were crossed for PONV. The need for rescue antiemetic was lower in the combination PC6 acupoint stimulation and antiemetic group than the antiemetic group (RR 0.61, 95% CI 0.44 to 0.86; 5 trials, 419 participants).The side effects associated with PC6 acupoint stimulation were minor, transient and self-limiting (e.g. skin irritation, blistering, redness and pain) in 14 trials. Publication bias was not apparent in the contour-enhanced funnel plots. AUTHORS' CONCLUSIONS There is low-quality evidence supporting the use of PC6 acupoint stimulation over sham. Compared to the last update in 2009, no further sham comparison trials are needed. We found that there is moderate-quality evidence showing no difference between PC6 acupoint stimulation and antiemetic drugs to prevent PONV. Further PC6 acupoint stimulation versus antiemetic trials are futile in showing a significant difference, which is a new finding in this update. There is inconclusive evidence supporting the use of a combined strategy of PC6 acupoint stimulation and antiemetic drug over drug prophylaxis, and further high-quality trials are needed.
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Affiliation(s)
- Anna Lee
- The Chinese University of Hong KongDepartment of Anaesthesia and Intensive CarePrince of Wales HospitalShatinNew TerritoriesHong Kong
- The Chinese University of Hong KongHong Kong Branch of The Chinese Cochrane Centre, The Jockey Club School of Public Health and Primary Care, Faculty of MedicineShatinNew TerritoriesHong Kong
| | - Simon KC Chan
- The Chinese University of Hong KongDepartment of Anaesthesia and Intensive CarePrince of Wales HospitalShatinNew TerritoriesHong Kong
| | - Lawrence TY Fan
- The Chinese University of Hong KongDepartment of Anaesthesia and Intensive CarePrince of Wales HospitalShatinNew TerritoriesHong Kong
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Randomized controlled trials on complementary and traditional medicine in the korean literature. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2014; 2014:194047. [PMID: 25628747 PMCID: PMC4290637 DOI: 10.1155/2014/194047] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 11/28/2014] [Accepted: 11/28/2014] [Indexed: 11/24/2022]
Abstract
Objective. This study aimed to identify all of the features of complementary and alternative (CAM) randomized controlled trials (RCTs) in the Korean literature and then introduce English-speaking researchers to the bibliometric and risk of bias characteristics of this literature. Methods. Eleven electronic databases and sixteen Korean journals were searched to August 2013 for RCTs of CAM therapies. Key study characteristics were extracted and risk of bias was assessed using the Cochrane Collaboration's tool for assessing risk of bias. Results. Three hundred and sixty publications met our inclusion criteria. Complementary and traditional medicine RCTs in the Korean literature emerged in the mid-1990s and increased in the mid-2000s. The most common CAM interventions include acupuncture (59.4%) and herbal medicine (8.3%). The largest proportion of trials evaluated CAM for musculoskeletal conditions (20.7%). Adequate methods of randomization were reported in 41.7% of the RCTs, whereas only 8.3% reported adequate allocation concealment. A low proportion of trials reported participant blinding (34.2%) and outcome assessor blinding (22.5%). Conclusions. Korean CAM RCTs are typically omitted from systematic reviews resulting in the potential for language bias. This study will enable these trials of diverse quality to be identified and assessed for inclusion in future systematic reviews on CAM interventions.
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Kim KH, Kang JW, Lee MS, Lee JD. Assessment of the quality of reporting in randomised controlled trials of acupuncture in the Korean literature using the CONSORT statement and STRICTA guidelines. BMJ Open 2014; 4:e005068. [PMID: 25079926 PMCID: PMC4120411 DOI: 10.1136/bmjopen-2014-005068] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 07/01/2014] [Accepted: 07/04/2014] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVES This study aims to assess the completeness of reporting of randomised controlled trials (RCTs) of acupuncture in the Korean literature. DESIGN Systematic review. METHODS We searched 12 Korean databases and 7 Korean journals to identify eligible RCTs of acupuncture published from 1996 to July 2011. We used the Consolidated Standards of Reporting Trials (CONSORT) checklist for parallel RCTs and the revised STandards for Reporting Interventions in Clinical Trials of Acupuncture (STRICTA) to assess the quality of reporting in Korean RCTs. We compared the completeness of reporting of CONSORT and STRICTA items in RCTs published in two time periods (1996-2004 referred to as the early period and 2005-2011 referred to as the late period). RESULTS We analysed 146 eligible RCTs using the CONSORT statement concerning RCTs of both needling and non-needling acupuncture and the STRICTA guidelines for 90 trials of needling acupuncture. Among the 103 RCTs in the late period, the proportion of RCTs that completely reported the CONSORT items of outcome definition (15.5%), sample size calculation (2.9%), randomisation (56%), allocation concealment (5.8%), implementation of allocation (11.7%), outcome assessor blinding (20.3%), flow of participants (25.2%), number of participants analysed (19.4%), ancillary analyses (0.0%), adverse events (24.3%), generalisability of findings (1.9%) and overall evidence (32.0%) remained small. Among the 61 RCTs of needling acupuncture in the late period, the STRICTA items of setting/context (24.6%) and practitioner background (27.9%) showed incomplete reporting. The completeness of reporting improved over time in several CONSORT and STRICTA items. CONCLUSIONS The completeness of reporting of Korean RCTs of acupuncture was suboptimal according to the CONSORT and revised STRICTA statements. Trial authors and journal editors should use the CONSORT statement and STRICTA guidelines for transparent reporting in Korean RCTs of acupuncture. The endorsement of the CONSORT and revised STRICTA statements in author instructions is also required.
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Affiliation(s)
- Kun Hyung Kim
- School of Korean Medicine, Pusan National University, Yangsan, South Korea
| | - Jung Won Kang
- Department of Acupuncture & Moxibustion, College of Korean Medicine, Kyung Hee University, Seoul, South Korea
| | - Myeong Soo Lee
- Korea Institute of Oriental Medicine, Daejeon, South Korea
| | - Jae-Dong Lee
- Department of Acupuncture & Moxibustion, College of Korean Medicine, Kyung Hee University, Seoul, South Korea
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Busse JW, Bruno P, Malik K, Connell G, Torrance D, Ngo T, Kirmayr K, Avrahami D, Riva JJ, Ebrahim S, Struijs PAA, Brunarski D, Burnie SJ, LeBlanc F, Coomes EA, Steenstra IA, Slack T, Rodine R, Jim J, Montori VM, Guyatt GH. An efficient strategy allowed English-speaking reviewers to identify foreign-language articles eligible for a systematic review. J Clin Epidemiol 2014; 67:547-53. [PMID: 24613496 DOI: 10.1016/j.jclinepi.2013.07.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 07/15/2013] [Accepted: 07/22/2013] [Indexed: 11/30/2022]
Abstract
OBJECTIVE To assess English-speaking reviewers' accuracy in determining the eligibility of foreign-language articles for a systematic review. STUDY DESIGN AND SETTINGS Systematic review of randomized controlled trials of therapy for fibromyalgia. Guided by 10 questions, English-speaking reviewers screened non-English-language articles for eligibility. Teams of two native-language speakers provided reference standard judgments of eligibility. RESULTS Of 15,466 potentially eligible articles, we retrieved 763 in full text, of which 133 were published in 19 non-English languages; 53 trials published in 11 languages other than English proved eligible. Of the 53 eligible articles, English-language reviewers guided by the 10 questions mistakenly judged 6 as ineligible; of the 80 ineligible articles, 8 were incorrectly judged eligible by English-language reviewers (sensitivity=0.89; specificity=0.90). Use of a simple three-step rule (excluding languages with less than three articles, reviewing titles and abstracts for clear indications of eligibility, and noting the lack of a clearly reported statistical analysis unless the word "random" appears) led to accurate classification of 51 of 53 articles (sensitivity=0.96; specificity=0.70). CONCLUSION Our findings show promise for limiting the need for non-English-language review teams in systematic reviews with large numbers of potentially eligible non-English-language articles.
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Affiliation(s)
- Jason W Busse
- Department of Anesthesia, McMaster University, HSC-2U1, 1200 Main Street West, Hamilton, Ontario, Canada L8S 4K1; Department of Clinical Epidemiology and Biostatistics, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1; The Michael G. DeGroote Institute for Pain Research and Care, McMaster University, MDCL 2101, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1.
| | - Paul Bruno
- Faculty of Kinesiology and Health Studies, University of Regina, 3737 Wascana Pkwy, Regina, Saskatchewan, Canada S4S 0A2
| | - Keshena Malik
- School of Rehabilitation Science, McMaster University, 1400 Main St. W., Hamilton, Ontario, Canada L8S 1C7
| | - Gaelan Connell
- Canadian Memorial Chiropractic College, 6100 Leslie St, Toronto, Ontario, Canada M2H 3J1
| | - David Torrance
- Canadian Memorial Chiropractic College, 6100 Leslie St, Toronto, Ontario, Canada M2H 3J1
| | - Trung Ngo
- Canadian Memorial Chiropractic College, 6100 Leslie St, Toronto, Ontario, Canada M2H 3J1
| | - Karin Kirmayr
- German Hospital, 1640 Pueyrredón, C1118 AAT, Buenos Aires, Argentina
| | - Daniel Avrahami
- Canadian Memorial Chiropractic College, 6100 Leslie St, Toronto, Ontario, Canada M2H 3J1
| | - John J Riva
- Department of Clinical Epidemiology and Biostatistics, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1; Department of Family Medicine, McMaster University, The Atrium at McMaster Innovation Park, 175 Longwood Road South, Hamilton, Ontario, Canada L8P 0A1
| | - Shanil Ebrahim
- Department of Anesthesia, McMaster University, HSC-2U1, 1200 Main Street West, Hamilton, Ontario, Canada L8S 4K1; Department of Clinical Epidemiology and Biostatistics, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1; Stanford Prevention Research Center, Department of Medicine, Stanford University, 1265 Welch Road, Stanford, California, USA 94305; Department of Anaesthesia & Pain Medicine, The Hospital for Sick Children, 555 University Ave, Toronto, Ontario, Canada M5G 1X8
| | - Peter A A Struijs
- Department of orthopaedic surgery, Academic Medical Center, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - David Brunarski
- Ontario Chiropractic Association, 20 Victoria St., Suite 200 Toronto, Ontario, Canada M5C 2N8
| | - Stephen J Burnie
- Canadian Memorial Chiropractic College, 6100 Leslie St, Toronto, Ontario, Canada M2H 3J1
| | - Frances LeBlanc
- Canadian Memorial Chiropractic College, 6100 Leslie St, Toronto, Ontario, Canada M2H 3J1; Canadian Chiropractic Association, 186 Spadina Avenue, Suite 6, Toronto, Ontario, Canada M5T 3B2
| | - Eric A Coomes
- University of Toronto, Faculty of Medicine, 1 King's College Circle Toronto, Ontario, Canada M5S 1A8
| | - Ivan A Steenstra
- The Institute for Work & Health, 8th floor, 481 University Ave., Toronto, Ontario, Canada M5G 2E9; Dalla Lana School of Public Health, University of Toronto, 6th floor, 155 College St, Toronto, Ontario, Canada M5T 3M7
| | - Tesha Slack
- The Institute for Work & Health, 8th floor, 481 University Ave., Toronto, Ontario, Canada M5G 2E9
| | - Robert Rodine
- Restorative Health, 12 William St W, Smiths Falls, Ontario, Canada K7A 1M9
| | - Janey Jim
- Jointworks Chiropractic Inc., 3860 Main St, Vancouver, British Columbia, Canada V5V 3N9
| | - Victor M Montori
- Knowledge and Evaluation Research Unit, Mayo Clinic, 200 First Street SW, Plummer 3-35, Rochester, MN, USA 55905
| | - Gordon H Guyatt
- Department of Anesthesia, McMaster University, HSC-2U1, 1200 Main Street West, Hamilton, Ontario, Canada L8S 4K1
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Bibliometric and content analysis of the Cochrane Complementary Medicine Field specialized register of controlled trials. Syst Rev 2013; 2:51. [PMID: 23826877 PMCID: PMC3704678 DOI: 10.1186/2046-4053-2-51] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 06/05/2013] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND The identification of eligible controlled trials for systematic reviews of complementary and alternative medicine (CAM) interventions can be difficult. To increase access to these difficult to locate trials, the Cochrane Collaboration Complementary Medicine Field (CAM Field) has established a specialized register of citations of CAM controlled trials. The objective of this study is to describe the sources and characteristics of citations included in the CAM Field specialized register. METHODS Between 2006 and 2011, regular searches for citations of CAM trials in MEDLINE and the Cochrane Central Register of Controlled Trials (CENTRAL) were supplemented with contributions of controlled trial citations from international collaborators. The specialized register was 'frozen' for analysis in 2011, and frequencies were calculated for publication date, language, journal, presence in MEDLINE, type of intervention, and type of medical condition. RESULTS The CAM Field specialized register increased in size from under 5,000 controlled trial citations in 2006 to 44,840 citations in 2011. Most citations (60%) were from 2000 or later, and the majority (71%) were reported in English; the next most common language was Chinese (23%). The journals with the greatest number of citations were CAM journals published in Chinese and non-CAM nutrition journals published in English. More than one-third of register citations (36%) were not indexed in MEDLINE. The most common CAM intervention type in the register was non-vitamin, non-mineral dietary supplements (e.g., glucosamine, fish oil) (34%), followed by Chinese herbal medicines (e.g., Astragalus membranaceus, Schisandra chinensis) (27%). CONCLUSIONS The availability of the CAM Field specialized register presents both opportunities and challenges for CAM systematic reviewers. While the register provides access to thousands of difficult to locate trial citations, many of these trials are of low quality and may overestimate treatment effects. When including these trials in systematic reviews, adequate analysis of their risk of bias is of utmost importance.
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