Claims for improved survival from systemic corticosteroids in diverse conditions: an umbrella review

Contopoulos‐Ioannidis, Despina G.; Ioannidis, John P. A.

doi:10.1111/j.1365-2362.2011.02584.x

Cited by 12 publications

(7 citation statements)

References 52 publications

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“…17 Of course mortality is a hard endpoint and more difficult to manipulate than other endpoints, but even for mortality, selective analysis may achieve inflated effects, as recently shown by corticosteroid trials. 64 The presence of patterns showing small study effects is also suggestive (not conclusive) of selective reporting biases. 65 Small study effects may also influence the literature in nations with strong traditions of running clinical trials.…”

Section: Possible Explanationsmentioning

confidence: 99%

“…Meta-analysts may have contacted the authors of primary trials and obtained outcome information not reported in published reports, or they may have standardised outcomes, for example, to include all cause mortality and all available follow-up, whereas primary papers may have focused on subset analyses or other secondary analyses such as cause specific deaths. 64 Thus bias may be larger in the reports of primary trials than that seen in meta-analysis based data. Secondly, agreement in treatment effects between more developed and less developed countries does not necessarily mean that both estimates are correct; occasionally both may be equally biased.…”

Section: Potential Limitations Of the Studymentioning

confidence: 99%

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Comparative effect sizes in randomised trials from less developed and more developed countries: meta-epidemiological assessment

Panagiotou

Contopoulos‐Ioannidis

Ioannidis

2013

BMJ

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Objective To compare treatment effects from randomised trials conducted in more developed versus less developed countries.Design Meta-epidemiological study. Data sources Cochrane Database of Systematic Reviews (August 2012).Data extraction Meta-analyses with mortality outcomes including data from at least one randomised trial conducted in a less developed country and one in a more developed country. Relative risk estimates of more versus less developed countries were compared by calculating the relative relative risks for each topic and the summary relative relative risks across all topics. Similar analyses were performed for the primary binary outcome of each topic.Results 139 meta-analyses with mortality outcomes were eligible. No nominally significant differences between more developed and less developed countries were found for 128 (92%) meta-analyses. However, differences were beyond chance in 11 (8%) cases, always showing more favourable treatment effects in trials from less developed countries. The summary relative relative risk was 1.12 (95% confidence interval 1.06 to 1.18; P<0.001; I 2 =0%), suggesting significantly more favourable mortality effects in trials from less developed countries. Results were similar for meta-analyses with nominally significant treatment effects for mortality (1.15), meta-analyses with recent trials (1.14), and when excluding trials from less developed countries that subsequently became more developed (1.12). For the primary binary outcomes (127 meta-analyses), 20 topics had differences in treatment effects beyond chance (more favourable in less developed countries in 15/20 cases). ConclusionsTrials from less developed countries in a few cases show significantly more favourable treatment effects than trials in more developed countries and, on average, treatment effects are more favourable in less developed countries. These discrepancies may reflect biases in reporting or study design as well as genuine differences in baseline risk or treatment implementation and should be considers when generalising evidence across different settings. IntroductionThe predominant share of the global burden of disease is concentrated in less developed countries.1 However, until recently relative few trials were being conducted in these nations.2 3 Evidence on the management of many diseases affecting less developed countries often had to be tentatively extrapolated from studies performed in more developed countries with a longer standing tradition of conducting clinical research. This situation is currently changing. As participation rates in clinical trials decrease and cost increases in Western countries, 4-6 many organisations providing contracts for research are focusing on eastern Europe, 7 Asia, 8 and South America,9 where the cost of recruiting participants is low. By 2015, for example, 15% of clinical trials are expected to be conducted in India. 8 10 11 With the globalisation of international health, 12 results of studies done in countries without a longstanding tradition of c...

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Section: Possible Explanationsmentioning

confidence: 99%

Section: Potential Limitations Of the Studymentioning

confidence: 99%

Comparative effect sizes in randomised trials from less developed and more developed countries: meta-epidemiological assessment

Panagiotou

Contopoulos‐Ioannidis

Ioannidis

2013

BMJ

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“…Umbrella reviews can overcome these problems by assessing the level of the evidence provided by systematic reviews and meta-analyses 14 for each risk or protective factor, through strict criteria that probe a standard list of potential biases. These criteria have been extensively validated in various areas of medicine, such as neurology, oncology, nutrition medicine, internal medicine, psychiatry, paediatrics, dermatology and neurosurgery [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] . In the current study, we applied the umbrella review approach to the published evidence on risk or protective factors for psychotic disorders.…”

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confidence: 99%

What causes psychosis? An umbrella review of risk and protective factors

et al. 2018

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Psychosis is a heterogeneous psychiatric condition for which a multitude of risk and protective factors have been suggested. This umbrella review aimed to classify the strength of evidence for the associations between each factor and psychotic disorders whilst controlling for several biases. The Web of Knowledge database was searched to identify systematic reviews and meta-analyses of observational studies which examined associations between socio-demographic, parental, perinatal, later factors or antecedents and psychotic disorders, and which included a comparison group of healthy controls, published from 1965 to January 31, 2017. The literature search and data extraction followed PRISMA and MOOSE guidelines. The association between each factor and ICD or DSM diagnoses of non-organic psychotic disorders was graded into convincing, highly suggestive, suggestive, weak, or non-significant according to a standardized classification based on: number of psychotic cases, random-effects p value, largest study 95% confidence interval, heterogeneity between studies, 95% prediction interval, small study effect, and excess significance bias. In order to assess evidence for temporality of association, we also conducted sensitivity analyses restricted to data from prospective studies. Fifty-five meta-analyses or systematic reviews were included in the umbrella review, corresponding to 683 individual studies and 170 putative risk or protective factors for psychotic disorders. Only the ultra-high-risk state for psychosis (odds ratio, OR59.32, 95% CI: 4.91-17.72) and Black-Caribbean ethnicity in England (OR54.87, 95% CI: 3.96-6.00) showed convincing evidence of association. Six factors were highly suggestive (ethnic minority in low ethnic density area, second generation immigrants, trait anhedonia, premorbid IQ, minor physical anomalies, and olfactory identification ability), and nine were suggestive (urbanicity, ethnic minority in high ethnic density area, first generation immigrants, North-African immigrants in Europe, winter/spring season of birth in Northern hemisphere, childhood social withdrawal, childhood trauma, Toxoplasma gondii IgG, and non-right handedness). When only prospective studies were considered, the evidence was convincing for ultra-high-risk state and suggestive for urbanicity only. In summary, this umbrella review found several factors to be associated with psychotic disorders with different levels of evidence. These risk or protective factors represent a starting point for further etiopathological research and for the improvement of the prediction of psychosis.

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“…By concentrating on each condition individually, guideline writers and opinion leaders may be too hasty in reaching a conclusion that the treatment should not be recommendeddborrowing strength by extrapolating across cancer types may reduce the risk of false-negative study results, especially where the result is imprecise, and there are no compelling biological reasons for diseasespecific effects. Conversely, cautions can be raised on adopting an apparently promising intervention with postulated benefits in many disease areas when examination of evidence does not suggest a consistent effectiveness across different indications [18].…”

Section: Improving Estimates Of Effectivenessmentioning

confidence: 99%

Scientific hypotheses can be tested by comparing the effects of one treatment over many diseases in a systematic review

Chen

Hemming

Chilton

et al. 2014

Journal of Clinical Epidemiology

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Claims for improved survival from systemic corticosteroids in diverse conditions: an umbrella review

Abstract: Background Systemic corticosteroids have been proposed for numerous indications and there are many claims that corticosteroids can reduce mortality in diverse conditions.

Cited by 12 publications

References 52 publications

Comparative effect sizes in randomised trials from less developed and more developed countries: meta-epidemiological assessment

Comparative effect sizes in randomised trials from less developed and more developed countries: meta-epidemiological assessment

What causes psychosis? An umbrella review of risk and protective factors

Scientific hypotheses can be tested by comparing the effects of one treatment over many diseases in a systematic review

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