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PubMed2025

Spectrum of genetic variants associated with maple syrup urine disease in the Middle East, North Africa, and Türkiye (MENAT): a systematic review.

BACKGROUND: Maple syrup urine disease (MSUD) is a hereditary metabolic disorder caused by a deficiency in the branched-chain α-keto acid dehydrogenase (BCKD) enzymatic complex. The Middle East and North Africa, and Türkiye (MENAT) region has witnessed a significant rise in the prevalence of MSUD due to high rates of consanguinity. Despite numerous genetic association studies, the complex relationships between genotype and phenotype in MSUD remain elusive. AIM: This study aimed to systematically review the variants significantly associated with MSUD in the MENAT region. METHODS: We systematically searched four literature databases (PubMed, Scopus, Web of Science, and Science Direct) from inception until December 2023 to gather all reported genetic data pertaining to MSUD in the MENAT region. Quality assessment and data extraction were diligently performed by a team of six investigators. RESULTS: A total of 16 studies, involving patients, were included in this systematic review. Among them, 211 patients presented with 105 variants located within genes known to be associated with MSUD. The majority of the identified MSUD variants were found in BCKDHA (38%), followed by BCKDHB (38%), DBT (23%), and PPM1K (1%). Notably, 77% of the captured variants were unique to the MENAT region. CONCLUSION: Our systematic review reveals a distinctive genetic and clinical susceptibility profile of MSUD among individuals from the MENAT region. These findings highlight the importance of understanding the specific genetic landscape of MSUD in this population. Further research is warranted to elucidate the complex genotype-phenotype relationships in MSUD in the MENAT region.

Humans↗
PubMed2004

WHO systematic review of maternal mortality and morbidity: methodological issues and challenges.

BACKGROUND: Reducing maternal mortality and morbidity are among the key international development goals. A prerequisite for monitoring the progress towards attainment of these goals is accurate assessment of the levels of mortality and morbidity. In order to contribute to mapping the global burden of reproductive ill-health, we are conducting a systematic review of incidence and prevalence of maternal mortality and morbidity. METHODS: We followed the standard methodology for systematic reviews. We prepared a protocol and a form for data extraction that identify key characteristics on study and reporting quality. An extensive search was conducted for the years 1997-2002 including electronic and hand searching. RESULTS: We screened the titles and abstracts of about 65,000 citations identified through 11 electronic databases as well as various other sources. Four thousand six hundred and twenty-six full-text reports were critically appraised and 2443 are included in the review so far. Approximately one third of the studies were conducted in Asia and Africa. The reporting quality was generally low with definitions for conditions and the diagnostic methods often not reported. CONCLUSIONS: There are unique challenges and issues regarding the search, critical appraisal and summarizing epidemiological data in this systematic review of prevalence/incidence studies. More methodological studies and discussion to advance the field will be useful. Considerable efforts including leadership, consensus building and resources are required to improve the standards of monitoring burden of disease.

Adult↗
PubMed2003

Elective cervical cerclage for prevention of preterm birth: a systematic review.

BACKGROUND: Elective cervical cerclage has been purported to prevent spontaneous preterm birth. We present a systematic review to determine the effectiveness of cervical cerclage in preventing spontaneous preterm birth before 34 weeks' gestation. METHODS: Searches were conducted in MEDLINE, EMBASE, Cochrane Library, and Science Citation Index to identify randomized trials published between 1966 and 2002. All randomized trials that evaluated the effectiveness of elective cerclage compared with no cerclage in women who were at risk of preterm birth before 34 weeks' gestation were included for analysis. Quality assessment and data extraction were performed in duplicate. RESULTS: There were seven relevant trials, comprising 2354 women. Meta-analysis was inappropriate because of large differences in the quality of the studies. However, in the largest single trial of good quality, cerclage was shown to prevent birth before 34 weeks' gestation. In this single study the reported number to be treated to prevent one additional preterm birth before 34 weeks was 24 women (95% CI: 10-61). The results of other trials were consistent with the finding of the largest trial. Data on complications were sparse and inconclusive. CONCLUSION: Our systematic review shows that elective cervical cerclage has a significant effect in preventing spontaneous preterm birth before 34 weeks' gestation. Further research should focus on identification and quantification of possible complications, and of risk factors and tests that identify high-risk women who would benefit most from cerclage.

Cerclage, Cervical↗
PubMed2007

Systematic review of comparative studies examining alternatives to the harmful use of animals in biomedical education.

OBJECTIVE: To systematically review the published literature for controlled studies comparing learning outcomes of traditional methods that require the terminal use of animals (eg, dissection, live-animal surgery, and live-animal laboratory demonstrations) with outcomes obtained with alternative teaching methods. DESIGN: Systematic review. STUDY POPULATION: Controlled studies published between 1996 and 2004. PROCEDURES: PubMed was searched with the following keywords, used alone and in combination: educational alternatives, nonlethal teaching methods, veterinary alternatives, medical education, and nonterminal animal use. Cited references of retrieved reports were reviewed to identify additional reports. Reports were selected for review only if a comparison group was included. RESULTS: 17 studies that were randomized controlled trials or nonrandomized trials that included a comparison group were identified. Five involved veterinary students, 3 involved medical students, 6 involved university undergraduate students, and 3 involved high school biology students. Sample size ranged from 14 to 283 students. Eleven studies appeared to be randomized, parallel-group trials, 4 involved comparative groups to which participants were not randomly assigned or for which the randomization process was not clear, 1 was a 2-period crossover study, and 1 involved a retrospective review of grades. In all 17 studies reviewed, results associated with the alternative method of instruction were not significantly different from or superior to results associated with the conventional method. CONCLUSIONS AND CLINICAL RELEVANCE: Although the number of controlled studies identified was small, the results seem to support more widespread adoption of alternative teaching methods in biomedical education.

Animal Welfare↗
PubMed2004

[Preventive home visits to the elderly: systematic review of available evidence].

The aim of preventive home visits to elderly persons is to reduce mortality, to avoid admissions to nursing homes and hospitals and to improve the functional status and general wellbeing of the elderly. Preventive home visits are rarely a standard service in national health care systems. For over 20 years, controlled randomized studies have been carried out to test their effectiveness. This systematic review evaluates the evidence available on preventive home visits for elderly persons in the context of considerations relating to the incorporation of such a service into the German health care system. Three current systematic reviews (two of them meta-analyses) were identified in a systematic literature survey. They consider a total of 26 studies, most of them RCTs. A further three original controlled studies were identified and evaluated. The original studies were very heterogeneous with respect to goals, target groups, intensity and duration of the home visit programme and with respect to the individuals performing the study (number, profession, qualifications and cooperation). This makes it more difficult to perform a pooled overall evaluation. It was possible to consider mortality, admissions to nursing homes, functional status and psychosocial status as relevant target parameters. The systematic reviews arrive at different assessments of effectiveness. A quantitative, across-studies evaluation demonstrated that preventive home visits to elderly persons were effective both in studies with selected and with unselected inclusion of participants. The second meta-analysis did not confirm this result. Effectiveness here was only demonstrated using stratified analyses which investigated a large number of home visits, the performance of a multidimensional assessment with follow-up visits and the average age and morbidity of participants as relevant influencing factors. However no factor exerted an influence over more than one of the investigated target parameters. The findings thus constitute very unspecific evidence of effectiveness with largely unclear determinants of success. Preventive home visit programmes have been tested in various health systems. Results from controlled (randomised) German studies have not been published to date. The results of studies from other countries have only limited applicability to the conditions in the German health care system because the opportunities for, and extent of, economical and effective improvement in the preventive care of the elderly depend on the standard of care existing in the individual country. The additional value of screening depends on the empirical level of care and not on a given standard. At present the introduction of home visits in Germany cannot be recommended beyond studies. However there appear to be sufficient reasons for controlled studies in Germany which should be carried out in a coordinated way with mutual agreement on concepts.

Aged↗
PubMed2005

[Portable coagulometers: a systematic review of the evidence on self-management of oral anticoagulant treatment].

BACKGROUND AND OBJECTIVE: We aimed to systematically review the scientific evidence about the use of portable coagulometers for patient's self-management of oral anticoagulant treatment. MATERIAL AND METHOD: Systematic review of scientific evidence available from MEDLINE'S, DARE's, HTA-Database's, NHS-EED's and The Cochrane Library' s bibliographic databases, from their origin to March 2003. Randomized control trials (RCT) and Quasi-Experimental trials were selected provided that they compared patients in self-management with patients under usual care. The quality of scientific evidence was elicited using the Scottish Intercollegiate Guideline Network (SIGN) recommendations, whilst efficacy and security were descriptively summarized. RESULTS: Twelve (7 RCT and 5 quasi-experimental trials) articles were found, and only two of them provided grade A recommendation. Patients under self-management remained the same or more time in the therapeutic range. The incidence of adverse effects in self-management patients was the same or less than that in patients under usual care. CONCLUSIONS: The quality of the scientific evidence is heterogeneous. For selected patients, patient's self-management is at least as effective and safe as usual care. New oral anticaogulants, which have shown promising results, should be scrutinized for future changes in service provision.

Administration, Oral↗
PubMed2005

EDTA chelation therapy for cardiovascular disease: a systematic review.

BACKGROUND: Numerous practitioners of both conventional and complementary and alternative medicine throughout North America and Europe claim that chelation therapy with EDTA is an effective means to both control and treat cardiovascular disease. These claims are controversial, and several randomized controlled trials have been completed dealing with this topic. To address this issue we conducted a systematic review to evaluate the best available evidence for the use of EDTA chelation therapy in the treatment of cardiovascular disease. METHODS: We conducted a systematic review of 7 databases from inception to May 2005. Hand searches were conducted in review articles and in any of the trials found. Experts in the field were contacted and registries of clinical trials were searched for unpublished data. To be included in the final systematic review, the studies had to be randomized controlled clinical trials. RESULTS: A total of seven articles were found assessing EDTA chelation for the treatment of cardiovascular disease. Two of these articles were subgroup analyses of one RCT that looked at different clinical outcomes. Of the remaining five studies, two smaller studies found a beneficial effect whereas the other three exhibited no benefit for cardiovascular disease from the use of EDTA chelation therapy. Adverse effects were rare but those of note included a few cases of hypocalcemia and a single case of increased creatinine in a patient on the EDTA intervention. CONCLUSION: The best available evidence does not support the therapeutic use of EDTA chelation therapy in the treatment of cardiovascular disease. Although not considered to be a highly invasive or harmful therapy, it is possible that the use of EDTA chelation therapy in lieu of proven therapy may result in causing indirect harm to the patient.

Cardiovascular Diseases↗
PubMedDate not supplied

[Quality of life assessment in laryngectomized patients: a systematic review].

Laryngectomy is the main sequela in patients with cancer of the larynx. The authors conducted a systematic review to evaluate the relationship between quality of life and laryngectomy. Ninety-six articles published in scientific journals were identified, and 35 were selected whose main focus was laryngectomy and quality of life in laryngectomized patients. Each article was evaluated by way of systematic review. Evaluation of the qualitative attributes of articles used the Qualitative Assessment Questionnaire (QAQ), a validated and tested instrument. Most articles lacked consistency and methodological rigor in measuring quality of life among laryngectomized patients. The relationship between quality of life and laryngectomy also fell far short of the multidimensional approach of the quality of life construct as suggested by the WHO/QOL (World Health Organization/Quality of Life) group.

Humans↗
PubMed2006

Spinal cord stimulation in complex regional pain syndrome and refractory neuropathic back and leg pain/failed back surgery syndrome: results of a systematic review and meta-analysis.

The drive for good quality evidence has highlighted the importance of well-conducted systematic reviews and meta-analyses that critically evaluate and grade studies for new or existing therapies. A systematic review and meta-analysis was performed to review the efficacy, safety, and cost effectiveness of spinal cord stimulation (SCS) in complex regional pain syndrome (CRPS) and refractory neuropathic back and leg pain/failed back surgery syndrome (FBSS). The results support the use of SCS in patients with refractory neuropathic back and leg pain/FBSS (Grade B evidence) and CRPS type I (Grade A evidence)/type II (Grade D evidence). SCS not only reduces pain, improves quality of life, reduces analgesic consumption, and allows some patients to return to work, with minimal significant adverse events, but may also result in significant cost savings over time.

Back Pain↗
PubMed2005

Seroprevalence of hepatitis A infection in a low endemicity country: a systematic review.

BACKGROUND: In Canada--a low endemicity country, vaccines for hepatitis A virus (HAV) are currently recommended to individuals at increased risk for infection or its complications. Applying these recommendations is difficult because the epidemiology of HAV infection is poorly defined, complex, and changing. This systematic review aimed to 1) estimate age-specific prevalence of HAV antibody in Canada and 2) evaluate infection-associated risk factors. METHODS: MEDLINE (1966-2005) and EMBASE (1980-2005) were searched to identify relevant studies for the systematic review. Archives for the Canada Diseases Weekly Report (1975-1991) and Canada Communicable Disease Report (1992-2005) were searched for relevant public health reports. Data were abstracted for study and participants' characteristics, age-specific prevalence, and risk factors. RESULTS: A total of 36 reports describing 34 unique studies were included.The seroprevalence in Canadian-born children was approximately 1% in ages 8-13, 1-6% in 20-24, 10% in 25-29, 17% in 30-39, and increased subsequently. In age groups below 20 and 20-29, age-specific seroprevalence generally remained constant for studies conducted across geographic areas and over time. Compared to Canadian-born individuals, subjects born outside Canada were approximately 6 times more likely to be seropositive (relative risk: 5.7 [95% CI 3.6, 9.0]). Travel to high risk areas in individuals aged 20-39 was associated with a significant increase in anti-HAV seropositivity (RR 2.8 [1.4, 5.5]). Compared to heterosexuals, men having sex with men were only at a marginally higher risk (adjusted odds ratio 2.4 [0.9, 6.1]). High risk for seropositivity was also observed for Canadian First Nations and Inuit populations. CONCLUSION: Results from the current systematic review show that in this low endemicity country, disease acquisition occurs in adulthood rather than childhood. The burden of disease is high; approximately 1 in 10 Canadians had been infected by ages 24-29. The increase in prevalence in young adults coincides with disease importation and increasing frequency of risk factors, most likely behavioral-related ones. Gaps in seroprevalence data were identified rendering the application of current immunization recommendations difficult. A nationwide prevalence survey for all Canadians is needed. This is essential to quantify the effectiveness of current recommendations and conduct cost-effectiveness evaluations of alternative immunization programs, if necessary.

Age Factors↗
PubMed2006

The Hardman index in patients operated on for ruptured abdominal aortic aneurysm: A systematic review.

BACKGROUND: The aims of the present study were to (1) analyze preoperative predictors for outcome suggested by Hardman and surgical mortality after open repair and endovascular repair (EVAR) of ruptured abdominal aortic aneurysms (rAAA), and (2) further evaluate the Hardman index in a systematic review. METHODS: Patients operated on for rAAA during a 5-year period between 2000 and 2004 were scored according to Hardman-1 point for either age >76 years, loss of consciousness after presentation, hemoglobin <90 g/L, serum creatinine >190 micromol/L or electrocardiographic (ECG) signs of ischemia-with blinded evaluation of ECGs by a specialist in clinical physiology. The results were included in a systematic review of studies evaluating the Hardman index. RESULTS: In-hospital mortality after operation was 41% (67/162). There was no difference in in-hospital mortality between open repair (n = 106) and EVAR (n = 56), whereas the Hardman index was associated with operative mortality in our institution and in the systematic review of 970 patients (P < .001). Mortality rate in patients with Hardman index > or =3 was 77% in the pooled analysis. A full data set of all five scoring variables was obtained in 94 (58%) of 162 patients in our study, and potential underscoring was thus possible in 68 patients. Of the available ECGs, 12 (8.7%) of 138 were judged nondiagnostic. Five studies did not state their missing data on ECG and hemoglobin and serum creatinine concentrations, nor did they specify the criteria for ECG ischemia. CONCLUSIONS: A strong correlation between the Hardman index and mortality was found. A Hardman index > or =3 cannot be used as an absolute limit for denial of surgery. The utility of the Hardman index seems to be impeded by variability in scoring resulting from missing or nondiagnostic data.

Aneurysm, Ruptured↗
PubMed2005

Identifying studies for systematic reviews of diagnostic tests was difficult due to the poor sensitivity and precision of methodologic filters and the lack of information in the abstract.

BACKGROUND AND OBJECTIVES: Methods to identify studies for systematic reviews of diagnostic accuracy are less well developed than for reviews of intervention studies. This study assessed (1) the sensitivity and precision of five published search strategies and (2) the reliability and accuracy of reviewers screening the results of the search strategy. METHODS: We compared the results of the search filters with the studies included in two systematic reviews, and assessed the interobserver reliability of two reviewers screening the list of articles generated by a search strategy. RESULTS: In the first review, the search strategy published by van der Weijden had the greatest sensitivity, and in the second, four search strategies had 100% sensitivity. There was "substantial" agreement between two reviewers, but in the first review each reviewer working on their own would have missed one paper eligible for inclusion in the review. Ascertainment intersection techniques indicate that it is unlikely that further papers have been missed in the screening process. CONCLUSION: Published search strategies may miss papers for reviews of diagnostic test accuracy. Papers are not easily identified as studies of diagnostic test accuracy, and the lack of information in the abstract makes it difficult to assess the eligibility for inclusion in a systematic review.

Abstracting and Indexing↗
PubMed2006

Information and low back pain management: a systematic review.

STUDY DESIGN: A systematic search of three electronic databases was done to identify randomized controlled trials on the effect of written or audiovisual information in low back pain. OBJECTIVES: To determine whether information is an effective preventive action and/or therapy for low back pain and which type of information is most effective. SUMMARY OF BACKGROUND DATA: Information is commonly used in the primary care of low back pain and mostly delivered by booklets. METHODS: A systematic computer-aided search of the Medline, PsyclInfo, and Embase database. A rating system was used to assess the strength of the evidence, based on the methodologic quality of the randomized controlled trials, the relevance of the outcome measures, and the consistency of the results. RESULTS: Eleven randomized controlled trials were selected, including seven trials of high methodologic quality, as well as one parallel group controlled survey and one longitudinal study. Only three of the seven high-quality studies showed favorable results for information. There is strong evidence that a booklet increases knowledge and moderate evidence that physician-related cues increase the confidence in a booklet and adherence to exercises. There is limited evidence that a biopsychosocial booklet is more efficient than a biomedical booklet to shift patient's beliefs about physical activity, pain, and consequences of low back trouble. There is strong evidence that booklets are not efficient on absenteeism and conflicting evidence that they are efficient on healthcare use. There is no evidence that e-mail discussion or video programs alone are effective to reduce low back pain, disability, and healthcare costs. CONCLUSIONS: Information based on a biopsychosocial model is recommended in primary care to shift patient beliefs on low back pain. Nevertheless, information delivery alone is not sufficient to prevent absenteeism and reduce healthcare costs.

Databases, Factual↗
PubMed2006

Systematic review of the qualitative literature on return to work after injury.

OBJECTIVES: This paper reports on a systematic review of the international qualitative research literature on return to work. This review was undertaken in order to better understand the dimensions, processes, and practices of return to work. Because return to work often includes early return before full recovery while a person is undergoing rehabilitation treatment, physical recovery is embedded in complicated ways with workplace processes and practices and social organization. These process-oriented dimensions of return to work are well described in the qualitative literature. METHODS: This systematic review of the literature covered peer-reviewed papers that focused on musculoskeletal and pain-related injuries and were published in English or French between 1990 and 2003. Findings from papers meeting relevance and quality criteria were synthesized using the meta-ethnographic approach. RESULTS: This review found that return to work extends beyond concerns about managing physical function to the complexities related to beliefs, roles, and perceptions of many players. Good will and trust are overarching conditions that are central to successful return-to-work arrangements. In addition, there are often social and communication barriers to return to work, and intermediary players have the potential to play a key role in facilitating this process. CONCLUSIONS: This paper identifies key mechanisms of workplace practice, process, and environment that can affect the success of return to work. The findings illustrate the contribution that qualitative literature can make to important aspects of implementation in relation to return to work.

Accidents, Occupational↗
PubMed2026

Positive psychology interventions during pregnancy: A systematic review.

Positive psychology interventions (PPI) have been applied and demonstrated evidence in various population groups. The present systematic review focused on the types and influence of PPI on the physical and psychological health of pregnant women. Studies that matched the selection criteria were identified on EBSCOhost, PsychINFO, Web of Science, PubMed, Scopus and four positive psychology journals. From the 2528 records identified, finally eight studies were included in the review. PPI in this review were delivered utilising various positive psychology components such as hope, gratitude and optimism based on existing theories, for example, the strengths theory, broaden-and-build theory, and hope theory. Most interventions were conducted from 14 gestational weeks onwards and were delivered via virtual platforms or mobile applications. As a result of this systematic review, it was identified that PPIs for maternal well-being were aimed at improving (1) physical health, including labour pain, nausea and vomiting; (2) psychological health, including stress, emotions, anxiety and depression; and (3) subjective health, including life satisfaction, perceived social support and quality of life. Most of the selected studies provided significant evidence towards improvement of well-being outcomes from administering PPI. For future studies, in-depth PPI integrated coping and support approaches should be further evidenced among diverse pregnant populations.

Humans↗
PubMed2005

Primary versus delayed wound closure in complicated appendicitis: an international systematic review and meta-analysis.

The purpose of this study was to determine, by means of a systematic review, whether the method of wound closure in complicated appendicitis affects the incidence of wound infection. A comprehensive literature search of multiple databases including MEDLINE (1980-2003), was performed, using the Cochrane search strategy, for articles on wound closure and complicated appendicitis. Clinical trials examining the method of wound closure were selected for systematic review and all quasi-randomized and randomized trials underwent meta-analysis. Failure to close the wound as planned in delayed closure (DC) was considered indicative of a wound infection. Purulent drainage requiring wound opening indicated an infection in the wounds closed primarily. Six randomized trials were considered adequate for meta-analysis. None independently showed a statistically significant difference in the risk of developing a wound infection with primary closure (PC). When pooled data were subjected to meta-analysis, PC achieved a statistically significant reduction in the relative risk of treatment failure and did not lead to an increase in wound infections. Primary closure does not increase the risk of developing a wound infection after operation for perforated appendicitis. Given the lack of benefit of DC, and the less traumatic, less painful, and less costly nature of PC; primary closure is a safe and practical treatment option.

Appendicitis↗
PubMed1991

Limitations in distinguishing malignant from benign lesions of the breast by systematic review of mammograms.

Our objective was to assess whether or not a systematic review of mammographic descriptors would result in improved classifications of nonpalpable lesions of the breast and reductions of biopsies for benign conditions. The prelocalization mammograms of 200 consecutive patients who had 231 biopsies were reviewed in random order by four radiologists experienced in mammography. Each reader assessed the presence of 32 specific descriptors regarding masses and calcifications. The following descriptors were highly associated with malignancy: for masses, inhomogeneous density; irregular shape; spiculated borders; and for calcifications, many calcifications; microcalcifications; linear or branching patterns, or both, and high spatial density. For masses, the descriptors highly associated with benignity were homogeneous density, oval shape and sharp or lobulated borders. For calcifications, the descriptors highly associated with benignity were solid, round and irregularly shaped. Readers indicated their over-all rating of each lesion, ranging from definitely benign to definitely malignant. Ratings were compared with the findings of pathologic reports (181 benign to 50 malignant), and receiver operating characteristic analyses were performed. The areas under the curves (A[z]) varied from 0.65 to 0.78. If biopsies had not been performed on those patients who were judged to have most likely benign lesions, one could reduce the number of biopsies for benign conditions by 48 to 69 per cent; however, 18 to 46 per cent of the malignancies would be missed. We conclude that diagnoses based on a systematic review of descriptors are not sufficiently accurate to reduce the number of mammary biopsies.

Adult↗
PubMed2004

[Bibliometric analysis of systematic reviews in the Neonatal Cochrane Collaboration. Its role in evidence-based decision making in neonatology].

INTRODUCTION: The Cochrane Neonatal Collaborative Review Group (CNRG) is one of the most important collaborative review groups registered in the Cochrane Collaboration (CC) and provides a growing and readily accessible source of information to help neonatologists base their care on detailed, critical, and up-to-date reviews of the best available evidence. The objective of this article was to perform a bibliometric analysis (quantitative and qualitative) of the systematic reviews (SR) published in the Neonatal Cochrane Collaboration (NCC) and to identify the subject areas studied by the CNRG in which decision-making in clinical practice is based on the best available evidence. METHODS: We performed a bibliometric analysis of the Cochrane Database of Systematic Reviews in Neonatology, Issue 2, 2003 (n = 147 SR). The following variables were registered in each SR: subject area of the study, authors (number and country), dates (last review and update), characteristics of the clinical trials included (number and type), characteristics of included newborns (number and gestational age), reviewers' conclusions and potential conflicts of interest. RESULTS: The main subject areas of studies in the NCC were respiratory diseases (69 SR) and gastroenterology-nutrition (23 SR). Reviews were relatively scarce on some subjects that are very important in clinical practice in neonatology, such as cardiovascular diseases (10 SR), neurology (10 SR) and infectious diseases (6 SR). All the SR dealt with interventions for the treatment or prevention of diseases of the newborn infant (mainly preterm) and we found no reviews on diagnostic tests. Eighty-two per cent of the SR were signed by 2 or 3 authors, and we found four Bradford's zones of productivity. Ninety-two percent of the authors of SR were from four countries (Australia, United States, United Kingdom and Canada). Seventy-nine percent of all SR were published between 2000 and 2002, and 48 % have been updated. The median number of clinical trials per SR was 5 (range 0-30) and the median number of newborns included per SR was 559 (range 0-5448). Sixty percent of SR also included quasi-randomized clinical trials, and 67 % of SR included only preterm infants. In 54 % of the SR, the reviewers' conclusion was sufficient to infer probable effects (favorable or unfavorable) in clinical practice, and potential conflicts of interest were registered in 22 %. DISCUSSION: Although CC reviews are based on specific guidelines, errors and biases occur, suggesting the need to "review the reviews". The bibliometric analysis of the NCC shows that the quality of published SR varies, and the main conclusion is that almost half of the reviewers' conclusions are insufficient to infer probable effects in clinical practice. There is a lack of scientific evidence on many therapies in neonatology and, at the moment, the SR published in the NCC enable evidence-based decision making mainly in the subject area of respiratory diseases and gastroenterology-nutrition. Challenges for the future include the need for bigger and better clinical trials in this field (with long-term outcomes among surviving children), the preparation of systematic reviews on topics not yet covered, and keeping an increasing number of reviews up-to-date. Every decision in neonatology should be based on a systematic appraisal of the best evidence available in the context of the prevailing values and resources at our disposal.

Bibliometrics↗