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Hempel S, Taylor SL, Solloway MR, et al. Evidence Map of Tai Chi [Internet]. Washington (DC): Department of Veterans Affairs (US); 2014 Sep.
This project provides an overview of the existing research evidence on Tai Chi. It combines a systematic review of systematic reviews with a scoping review for VA priority areas.
The systematic review of systematic reviews is registered in PROSPERO, an international database of prospectively registered systematic reviews in health and social care (record number CRD42014009907). Systematic reviews follow a standardized and resource-intense approach that aims to identify all critical studies to answer a particular research or policy question. Systematic reviews provide estimates of the research volume identified in multiple sources. Studies included in systematic reviews may be synthesized in a meta-analysis, a statistical technique to pool data across studies, which can detect treatment effects across individual small and underpowered studies. Given the breadth of the research field, broad indications of the clinical effect are based on results of RCTs, a rigorous research design which can provide strong evidence for the effectiveness of Tai Chi.
The primary client and technical expert panel (TEP) determined the outcomes and clinical indications pain, posttraumatic stress disorder (PTSD), and fall prevention to be VA priority areas. The published literature continues to grow and new RCTs may challenge existing summaries of the literature. Hence we have identified recently published RCTs not yet included in published systematic reviews for priority areas. In the absence of RCTs, other research designs were considered.
INCLUSION CRITERIA
To be included in the evidence map, publications had to meet the following criteria:
- Design: Systematic reviews focusing on Tai Chi and summarizing primary research studies were eligible for inclusion for all clinical indications. We defined systematic reviews as reviews that either self-identified as a “systematic review” or reviews that reported the search sources and accounted for identified studies. For the VA priority areas, recent RCTs focusing on Tai Chi, reporting patient outcomes, and not yet included in existing reviews were also reviewed and other research designs were considered in the absence of RCTs.
- Participants: Systematic reviews including human adult participants practicing Tai Chi for any health-related indication were eligible for inclusion in the evidence map. Systematic reviews of adult participants or unspecified age groups were included; systematic reviews exclusively focusing on children and adolescents were excluded.
- Intervention: Systematic reviews of the effects of Tai Chi for any clinical indication were eligible for inclusion. Systematic reviews addressing Tai Chi and other approaches were eligible if one of the two following criteria was met: (1) the term “Tai Chi” was part of the search strategy, or (2) the search strategy did not specify any interventions (eg, focused on an outcome) and the systematic review identified Tai Chi studies. We excluded systematic reviews that included Tai Chi studies but did not systematically search for these (eg, by reviewing “exercise” interventions where only those Tai Chi studies were found that used the descriptive term “exercise”), and broad reviews on complementary and alternative medicine approaches without particular focus on Tai Chi.
- Outcome: Patient health outcomes were eligible for inclusion. Systematic reviews of provider outcomes, acceptance, prevalence, use, costs, study design features, or intervention features not reporting patient health outcomes were excluded.
- Timing: Systematic reviews including any intervention duration and any followup point were eligible for inclusion.
- Setting: Systematic reviews of studies in healthcare-related settings were eligible for inclusion.
- English-language systematic reviews, regardless of the language of the included studies were eligible for inclusion. VA priority areas were searched without language restriction.
SEARCH
We searched the electronic databases PubMed using the systematic review clinical query; the Database of Abstracts of Reviews of Effects (DARE, a database dedicated to catalogue systematic reviews in healthcare); the Cochrane Library of Systematic Reviews (which keeps a record of all ongoing and completed Cochrane reviews); the Campbell Collaboration database; AMED (the Allied and Complementary Medicine database); CINAHL (which indexes nursing and allied health literature); PsycInfo (which is directed at psychological research), Scopus and the Web of Science (to capture sports literature), and the review registry PROSPERO without publication date restriction, to identify English-language systematic reviews focusing on Tai Chi published to February 2014. In addition, we screened published reviews of reviews and consulted topic experts.
In order not to miss any publications because of different spelling conventions, we used the terms “tai chi,” “tai-chi,” “tai ji,” “tai-ji,” “taiji,” “t'ai chi,” “t' ai chi,” “taijiquan,” and “shadow boxing.”
We also searched PubMed for Tai Chi RCTs, using the RCT search filter, without language restriction to identify recently published RCTs reporting on the outcome pain and/or falls, not yet included in existing systematic reviews. We searched PubMed, AMED, CINAHL, PsycInfo, Scopus, and the Web of Science without date, language, or study design restriction to identify PTSD publications not yet included in existing systematic reviews.
PROCEDURE
Two independent literature reviewers screened the systematic review search output. Citations deemed potentially relevant by at least one reviewer and unclear citations were obtained as full text. The full text publications were screened against the specified inclusion criteria by 2 independent reviewers; disagreements were resolved through discussion. The literature flow was documented in an electronic database and reasons for exclusion of full text publications were recorded. Results of individual reviews and recent RCTs were extracted in an online database for systematic reviews.
We removed data duplicates so that each systematic review entered the dataset only once (this entailed consolidating online-only and final publication of articles, Cochrane reviews published in the Cochrane database and in a journal article, multiple updates of Cochrane reviews, and references to systematic reviews differently indexed in general and specialist systematic review databases). Where originals and updates of systematic reviews by the same author group were available, only the most recent version was considered.
The search results of the scoping review for VA priority areas was screened in duplicate and the literature flow was documented in an electronic database.
DATA SYNTHESIS
We provide a general overview of the Tai Chi literature by mapping systematic review results and a more detailed research overview for the 3 priority areas pain, PTSD, and fall prevention.
From each included systematic review, we extracted the specific clinical indication targeted in the review (eg, osteoarthritis) and the main patient outcomes (eg, pain) that were summarized across included studies. We extracted the number of Tai Chi RCTs included in the review, the comparator, and treatment effect estimates for patient outcomes. Pooled results were extracted as reported; results were not reanalyzed. Additionally, we extracted review characteristics such as whether the review was a Cochrane review, indicating methodological rigor. We also extracted whether adverse events had been addressed, and documented which reviews were based on a format of Tai Chi that deviated from traditional formats (eg, no weight shifting component; water-based; sitting, not standing; limited training intensity).
Bubble plots
The evidence base of Tai Chi research was distilled into a visual overview using the format of bubble plots. Bubble plots use color to differentiate clinical indications and provide 3 dimensions to display information: the x-axis, y-axis, and the size of the bubble.
Clinical indications (number of bubbles): We used the topics of the individual systematic reviews as reported by the review authors to categorize the systematic reviews. Reviews focused on outcomes, populations, or clinical indications. All identified systematic reviews were allocated to a single content area and did not enter the bubble plot multiple times. Where reviews provided data for multiple content areas, results were described in the narrative synthesis.
Literature size (y-axis): The bubble plots provide an overview of the research volume or quantity for the identified clinical indications. For this estimate we used the number of included RCTs per review, selecting the systematic review with the most included Tai Chi RCTs for the individual topic as the research volume estimate. Reviews vary in their inclusion criteria for study designs (eg, whether or not they include observational studies). A well-established research design, such as RCTs, that is always likely to be included in reviews, provides a broad estimate of the research volume.
Effect (x-axis): The bubble plots provide a very broad indication of the clinical effectiveness of Tai Chi according to patient health outcomes reported in RCTs for each differentiated clinical indication. For each clinical topic, all available systematic reviews were reviewed. Most emphasis was given to the largest review (which should provide the most complete literature synthesis), Cochrane reviews (given their methodological quality), or reports from agencies specializing in unbiased systematic reviews such as the Agency for Healthcare Research and Quality (AHRQ). For effect size estimates, meta-analytic results were sought to provide a summary effect across individual and often small and underpowered studies.
Reviews (bubble size): We used the size of the bubble to document the number of systematic reviews identified in the systematic review of systematic reviews on Tai Chi.
Executive Summary
While the bubble plot can display only very limited information, the narrative synthesis in the executive summary provides more detailed information on the individual clinical indications, outcomes, treatment effect estimates, individual reviews, and included studies.
We differentiated areas with most research, areas with a smaller research base, and most promising areas, and provided more detailed information for each of the a priori identified priority areas.
Future Research
We identified evidence gaps by documenting topic areas for which systematic reviews exist but the reviews did not identify relevant RCTs (ie, high evidence level research studies). In addition, we documented clinical indications for which there is conflicting evidence across identified reviews or where reviews concluded that the existing evidence base is insufficient to come to firm conclusions.
We also documented ongoing systematic reviews registered in review registries that will become available to summarize a topic area in the near future. We identified Cochrane review protocols published in the Cochrane Database of Systematic Reviews in last 3 years and not yet published as a review, indicating an ongoing review. PROSPERO, the international registry of systematic reviews, was also searched to identify ongoing systematic reviews on Tai Chi.
TECHNICAL EXPERT PANEL
The technical expert panel (TEP) for the project included Stephen Ezeji-Okoye, MD, VHA Central Office Field Advisory Committee on Complementary and Alternative Medicine; Laura Krejci, Associate Director VA Office of Patient Centered Care and Cultural Transformation; Peter Asco, Therapy Assistant, Tai-Chi and Qi Gong Instructor at University of California Los Angeles and Tai Chi Program Developer; Ansgar Furst, PhD, MSc, Clinical Assistant Professor of Psychiatry and Behavioral Sciences and of Neurology & Neurological Sciences, Stanford University School of Medicine, Associate Director of Neuroimaging, War Related Illness and Injury Study Center, VA Palo Alto Health Care System; Laura Redwine PhD, Assistant Professor of Psychiatry University of California San Diego, Research Scientist Veterans Medical Research Foundation San Diego; Greg Patterson PhD, HSPP, Clinical Psychologist Oscar G. Johnson VA Medical Center; and Elmer Ligh MPT, Physical Therapist at Hunter Holmes McGuire Veterans Hospital in Richmond, Virginia.
PEER REVIEW
A draft version of the deliverable was reviewed by both technical experts and clinical leadership. Reviewer comments were incorporated in the final report and are documented in the appendix.
- METHODS - Evidence Map of Tai ChiMETHODS - Evidence Map of Tai Chi
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