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Systematic reviews summarize large amounts of information and are more likely than individual trials to describe the true clinical effect of an intervention. Traditional statistical outputs from systematic reviews cannot immediately be applied to clinical practice. The number needed to treat (NNT) has that clinical immediacy. This number can be calculated easily from raw data or from statistical outputs, and the principle involved in its calculation can be applied to different outcomes: treatment efficacy, adverse events (harm), or other end points. The NNT defines the treatment-specific effect of an intervention, and we suggest it as a currency for making decisions about individual patients. Knowing the NNT for different interventions that have the same outcome for the same disorder can help shape individual and institutional practice. Knowing or estimating the number needed to harm is also an important part of the equation. Knowing or estimating an individual patient's risk can, with the NNT, be a guide to the overall or net value of a prophylactic intervention. We advocate an approach to systematic reviews that distills information into, in effect, one number: the NNT. This is simple to remember and directly supports efforts to work with patients to make the best possible clinical decisions for their care.
BACKGROUND: An unbiased systematic review (SR) should analyse as many articles as possible in order to provide the best evidence available. However, many SR use only databases with high English-language content as sources for articles. Literatura Latino Americana e do Caribe em Ciências da Saúde (LILACS) indexes 670 journals from the Latin American and Caribbean health literature but is seldom used in these SR. Our objective is to evaluate if LILACS should be used as a routine source of articles for SR. METHODS: First we identified SR published in 1997 in five medical journals with a high impact factor. Then we searched LILACS for articles that could match the inclusion criteria of these SR. We also checked if the authors had already identified these articles located in LILACS. RESULTS: In all, 64 SR were identified. Two had already searched LILACS and were excluded. In 39 of 62 (63%) SR a LILACS search identified articles that matched the inclusion criteria. In 5 (8%) our search was inconclusive and in 18 (29%) no articles were found in LILACS. Therefore, in 71% (44/72) of cases, a LILACS search could have been useful to the authors. This proportion remains the same if we consider only the 37 SR that performed a meta-analysis. In only one case had the article identified in LILACS already been located elsewhere by the authors' strategy. CONCLUSION: LILACS is an under-explored and unique source of articles whose use can improve the quality of systematic reviews. This database should be used as a routine source to identify studies for systematic reviews.
AIMS: Previous systematic reviews have found that drug-related morbidity accounts for 4.3% of preventable hospital admissions. None, however, has identified the drugs most commonly responsible for preventable hospital admissions. The aims of this study were to estimate the percentage of preventable drug-related hospital admissions, the most common drug causes of preventable hospital admissions and the most common underlying causes of preventable drug-related admissions. METHODS: Bibliographic databases and reference lists from eligible articles and study authors were the sources for data. Seventeen prospective observational studies reporting the proportion of preventable drug-related hospital admissions, causative drugs and/or the underlying causes of hospital admissions were selected. Included studies used multiple reviewers and/or explicit criteria to assess causality and preventability of hospital admissions. Two investigators abstracted data from all included studies using a purpose-made data extraction form. RESULTS: From 13 papers the median percentage of preventable drug-related admissions to hospital was 3.7% (range 1.4-15.4). From nine papers the majority (51%) of preventable drug-related admissions involved either antiplatelets (16%), diuretics (16%), nonsteroidal anti-inflammatory drugs (11%) or anticoagulants (8%). From five studies the median proportion of preventable drug-related admissions associated with prescribing problems was 30.6% (range 11.1-41.8), with adherence problems 33.3% (range 20.9-41.7) and with monitoring problems 22.2% (range 0-31.3). CONCLUSIONS: Four groups of drugs account for more than 50% of the drug groups associated with preventable drug-related hospital admissions. Concentrating interventions on these drug groups could reduce appreciably the number of preventable drug-related admissions to hospital from primary care.
Several methods can be used to identify systematic reviews. These include bibliographic databases, such as MEDLINE, Best Evidence, and the Cochrane Library. In the future, the Cochrane Library could become the source of choice for systematic reviews because it provides the full text for Cochrane reviews and citations to many other systematic reviews. Moreover, the Library is growing rapidly and becoming more readily available, and its searching capabilities are being improved with each update. Although Best Evidence contains fewer systematic reviews than the Cochrane Library, it is specifically designed for practicing internists and primary care physicians and includes systematic reviews on diagnosis, cause, prognosis, and quality improvement. At present, however, MEDLINE and other bibliographic databases are probably the most up-to-date and readily available sources of systematic reviews. Systematic reviews are a powerful and useful way to assemble evidence; however, just because a review has been done using systematic review methods does not guarantee that its results are credible. Regardless of the source, all systematic reviews (like all types of research evidence) require critical appraisal to determine their validity and to establish whether and how they will be useful in practice.
Systematic reviews assist nurses, other health care providers, decision makers, and consumers in managing the explosion of health care information by synthesizing valid data and reporting the effects of interventions. Nurses are increasingly using systematic reviews to guide their practice and develop policy. The purpose of the article is to outline the steps involved in conducting a systematic review with examples taken from a systematic review titled "Strategies to Manage the Behavioral Symptoms Associated With Alzheimer's Disease." The steps of a systematic review include: (a) formulating a well-defined question, (b) developing relevance and validity tools, (c) conducting a comprehensive search to retrieve published and unpublished reports, (d) assessing the reports using relevance and validity tools, (e) data extraction, (f) synthesis of the findings, and (g) report writing. Understanding the steps involved in a systematic review will assist nurses in critically appraising reviews and in conducting their own reviews.
OBJECTIVE: To systematically review all published economic analyses of the only 2 available agents for respiratory syncytial virus immunoprophylaxis in high-risk infants: respiratory syncytial virus immunoglobulin intravenous and palivizumab. DATA SOURCES: Economic evaluations of respiratory syncytial virus immunoprophylactic agents were identified from the MEDLINE and HealthSTAR databases using various combinations of the following search terms: respiratory syncytial virus immunoglobulin intravenous, palivizumab, cost, and cost-effectiveness. The search was limited to articles published in English between January 1, 1990, and August 31, 2001. Additional studies were obtained by searching bibliographies of all relevant identified articles. STUDY SELECTION: Only studies that performed an economic analysis of either or both of these agents in an infant population were included. Letters to the editor and commentaries that included informal economic analyses were excluded. Twelve of the 21 identified studies met the selection criteria. DATA EXTRACTION: Two of us (S.K.-B. and J.D.) independently reviewed the articles and extracted summary information using a standardized abstraction form, with differences resolved by consensus. DATA SYNTHESIS: Estimates ranging from cost savings to considerable incremental costs per hospitalization avoided with use of either agent were observed across studies. Studies comparing the 2 agents reported mixed results about their relative cost-effectiveness in different infant subgroups. The divergent results may be explained by differences in the study methods and assumptions, but they also reflect the poor quality of some of the economic analyses. CONCLUSION: In light of the issues identified in this review, providers, payers, and health policymakers need to critically appraise and judiciously interpret cost-effectiveness research on these agents.
This qualitative systematic review of the clinical methodology used in randomised, controlled trials of oral opioids (morphine, hydromorphone, oxycodone) for cancer pain underlines the difficulties of good pain research in palliative care. The current literature lacks placebo-controlled superiority trials. Recommendations for future research are discussed.
OBJECTIVE: We systematically reviewed data on effects of increased access to emergency contraceptive pills on pregnancy rates and use of the pills. DATA SOURCES: We searched MEDLINE, POPLINE, EMBASE, and LILACS, and we consulted with experts. METHODS OF STUDY SELECTION: We included studies that compared the effect of different levels of access to emergency contraceptive pills on pregnancy rates, use of the pills, and other outcomes. TABULATION, INTEGRATION, AND RESULTS: Of the 717 articles identified, we selected 23 for review. The studies included randomized trials, cohort studies, and evaluations of community interventions. The quality of these studies varied. In all but one study, increased access to emergency contraceptive pills was associated with greater use. However, no study found an effect on pregnancy or abortion rates. CONCLUSION: Increased access to emergency contraceptive pills enhances use but has not been shown to reduce unintended pregnancy rates. Further research is needed to explain this finding and to define the best ways to use emergency contraception to produce a public health benefit.
OBJECTIVE: This systematic review examined group based injury prevention interventions that targeted young children to determine the effectiveness of such strategies in enhancing children's safety behaviors. METHODS: A comprehensive (manual and electronic) search of the literature was performed using the following study selection criteria: (1) intervention engaged children under the age of 6 years; (2) included a control group; (3) used a group intervention approach; (4) study written in English language; (5) addressed unintentional injuries; and (6) outcomes included injuries, knowledge, or safety behaviors. Data abstraction was performed independently by two researchers using a standardized approach. RESULTS: Nine studies met the criteria that included safety interventions of road crossing (4), car restraint (2), spinal cord safety (1), poison safety (1), and 911/stranger danger/street crossing (1). The types of interventions included videos, interactive activities, cartoons, stories, puppets, singing, coloring, games, simulation games, demonstrations, modeling/role playing, and rehearsal practice using seat belts, models, and real street crossing. The intensity and duration of interventions varied substantially and only two studies randomly assigned participants. The review revealed a positive effect (knowledge, behaviour, and/or attitude) for five of the studies, three had mixed effect, and one reported no effect. CONCLUSIONS: Although no clear conclusions can be drawn from the limited number of studies of diverse design and rigor, researchers should attempt to minimize shortcomings occurring in community based research. Engaging community partners including teachers and parents who influence relationships and outcomes could provide opportunity for more rigorous, comprehensive, and integrated approach to longitudinal research that could identify key factors of successful strategies.
BACKGROUND: A systematic review of the current data on swallowing function after radiotherapy or chemoradiotherapy is presented. METHODS: Electronic databases were searched for 1966-2005. Papers were categorized according to level of evidence, methodological quality, and the specific domain of swallowing being measured. RESULTS: Of 109 papers retrieved, 33 were identified and reviewed. Evidence was primarily classified as either level III.2 (cohort studies) or level IV (case series). Methodological quality was found to be compromised in most studies. Although many researchers had investigated swallowing impairment, a wide variety of measurement tools were employed. CONCLUSIONS: There are limited data on swallowing outcomes after radiotherapy or chemoradiotherapy for head and neck cancer. Further work is needed to ascertain which aspects of swallowing should be measured, and then to use such measures in well-designed clinical trials and prospective cohort studies of this under-researched population.
OBJECTIVE: A systematic review was performed to determine the most effective agent with which to sedate adult patients who have respiratory failure that requires mechanical ventilation in the medical intensive care unit. DATA SOURCES: A computerized literature search of MEDLINE, a U.S. National Library of Medicine online database, from 1966 to August 1998 was conducted. All selected articles were reviewed to identify other relevant articles. STUDY SELECTION: Inclusion criteria were as follows: a) population-adults with respiratory failure who received mechanical ventilation in a medical intensive care unit; b) design-prospective, randomized controlled trial; c) intervention-sedation; and d) primary outcome-successful sedation. DATA EXTRACTION: Of 71 potentially relevant articles, only 15 randomized trials fulfilled all four selection criteria. DATA SYNTHESIS: Clinical heterogeneity among studies precluded statistical pooling of results. CONCLUSIONS: More research is needed to determine the most effective agent with which to sedate adult patients who have respiratory failure that requires mechanical ventilation in the medical intensive care unit.
AIM: To systematically evaluate the effect of supplemental fluids or feedings during the first days of life on the overall breastfeeding duration and rate of exclusive breastfeeding among healthy infants. METHODS: Medical subject headings and free-language terms were used to search the following electronic databases for studies relevant to breastfeeding: MEDLINE, EMBASE, Cumulative Index to Nursing and Allied Health (CINAHL), the Cochrane Library, and La Leche League. Only randomized, controlled trials (RCT) were considered for study inclusion. RESULTS: Of 56 potentially relevant clinical trials identified, only one RCT (170 infants) met the inclusion criteria for this systematic review. In this study, formula feeding was significantly more frequent at 4 wk in the experimental group in which breastfeeding had been supplemented with 5% glucose ad libitum during the first 3 d of life (n = 83) than in the exclusively breastfed control group (n = 87) (p < 0.05). At 16 wk (5 mo postpartum), the percentage of mothers who continued breastfeeding, either exclusively or partially, was significantly lower in the experimental group than in the control group (p < 0.01). CONCLUSION: There remains considerable uncertainty about the effect of brief exposure to water, breast-milk substitutes, or other liquids on the success and duration of breastfeeding.
OBJECTIVE: To systematically review the effect of consumer use of online health information on decision-making, attitudes, knowledge, satisfaction and health outcomes and utilization. SEARCH STRATEGY: Electronic databases searched included the Cochrane Controlled Trials Register, MEDLINE, PREMEDLINE (to 14 March 2001), CINAHL, Australian Medical Index, Health and Society, National Institutes of Health Clinical Trials Database and CenterWatch. INCLUSION CRITERIA: All post-1995 comparative studies (including controlled studies, before and after studies, and interrupted time series analyses) of Internet users vs. non-Internet users and other communications mediums, and Internet characteristics such as e-mail vs. other communication mediums, were included. Outcomes included consumer decision-making, attitudes, knowledge, satisfaction and measurable changes in health status or health utilization. DATA EXTRACTION AND SYNTHESIS: One reviewer screened all papers then two reviewers independently assessed studies against the selection criteria and any discrepancies were resolved by discussion with a third reviewer. No attempt was made to combine the data for further statistical analysis. MAIN RESULTS: We identified 10 comparative studies. Studies evaluated the effectiveness of using the Internet to deliver a smoking cessation programme, cardiac and nutrition educational programmes, behavioural interventions for headache and weight loss, and pharmacy and augmentative services. All studies showed some positive effects on health outcomes, although the methodological quality of many studies was poor. CONCLUSIONS: Despite widespread consumer Internet use to obtain health-care information, there is almost a complete lack of evidence of any effects this may have on health outcomes.
AIMS: This systematic review summarises the existing evidence on acupuncture for cancer-related pain. METHODS: Literature searches were conducted in seven databases. All clinical studies of acupuncture, electroacupuncture and ear acupuncture in cancer patients with the main outcome measure of pain were included. Data were extracted according to pre-defined criteria by two independent reviewers and methodological quality was assessed using the Jadad scale. RESULTS: Of the seven studies included, one high quality randomised clinical trial of ear acupuncture showed statistically significant pain relief in comparison with placebo ear acupuncture. All the other studies were either non-blinded (n=2) or uncontrolled clinical trials (n=4). Most investigations suffered from methodological flaws such as inadequate study design, poor reporting of results, small sample size and overestimation of the results. CONCLUSIONS: The notion that acupuncture may be an effective analgesic adjunctive method for cancer patients is not supported by the data currently available from the majority of rigorous clinical trials. Because of its widespread acceptance, appropriately powered RCTs are needed.
PURPOSE: We systematically reviewed the available evidence, and obtained and compared summary estimates of the sensitivity and specificity of cytology and the urine based markers bladder tumor antigen, BTA stat (Polymedco, Redmond, Washington), BTA TRAK (Polymedco), NMP22 (Matritech, Cambridge, Massachusetts), telomerase and fibrin degradation product in detecting primary bladder cancer. MATERIALS AND METHODS: Studies on the diagnosis of primary bladder cancer published from 1990 through November 2001 in English and German were retrieved from MEDLINE and EMBASE data bases. In our research we included studies that evaluated 1 or more of the markers, used cystoscopy as the reference standard and allowed the construction of a 2 x 2 contingency table for a per patient analysis. The data plus items on study and clinical characteristics were extracted by 2 observers. Sensitivity and specificity for each marker were estimated using a bivariate random effect meta-analysis. A multivariable analysis was performed to explain study variation. RESULTS: A total of 42 studies were included in our review. Only 2 studies were available on fibrin degradation product, hence a meta-analysis was not possible. Cytology had the best specificity at 94% (95% CI: 90% to 96%). This figure was significantly better than that of the other markers except for telomerase (specificity 86% [71% to 94%]). Telomerase had the best sensitivity (75% [71% to 79%]) but it was not significantly better than that of BTA stat (70% [66% to 74%]). Case control designs yielded lower values for sensitivity for the tumor markers cytology, bladder tumor antigen and BTA stat. CONCLUSIONS: Cytology has the best specificity and telomerase the best sensitivity. However, none of the markers studied here is sensitive enough to be recommended for daily routine.
OBJECTIVE: A systematic review of the literature about chronic fatigue syndrome (CFS). METHODS: A search of the Medline database (via Ovid and PubMed) with the key words chronic fatigue syndrome, diagnosis, classification, epidemiology, etiology, physiopathology, metabolism, microbiology, immunology, virology, psychology, drug therapy, rehabilitation, and therapy. The reference lists of each article were examined for additional related articles. RESULTS: CFS was defined in 1988 by the US Centes for Disease Control and Prevention. The prevalence of chronic fatigue syndrome has ranged from 0.2% to 0.7% in the general population. In 1994, the definition of CFS was revised by Fukuda et al. Despite various research in several topics (e.g. infection, immune systems, neuroendocrinology, autonomic activity, neuromuscular involvement), the pathophysiology remains unknown. CONCLUSION: CFS, with its various major clinical and functional impacts, should be associated with a "biopsychosocial model". Progressive muscular rehabilitation, combined with behavioral and cognitive treatment, is an essential part of therapy.
OBJECTIVE: To systematically review educational or psychoeducational interventions for patients with rheumatoid arthritis focusing on long-term effects, especially health status. METHODS: Two independent reviewers appraised the methodologic quality of the included randomized controlled trials, published between 1980 and July 2002. RESULTS: Validity scores of studies ranged from 3 to 9 (of 11). The 7 educational programs mainly improved knowledge and compliance in the short and long term, but there was no improvement in health status. All 4 psychoeducational programs improved coping behavior in the short term, 2 of them showing a positive long-term effect on physical or psychological health variables. CONCLUSION: Methodologically better-designed studies had more difficulties demonstrating positive outcome results. Short-term effects in program targets are generally observed, whereas long-term changes in health status are not convincingly demonstrated. There is a need to find better strategies to enhance the transfer of short-term effects into gains in health status.