Abstract：
OBJECTIVES:To study the statistical power of randomized clinical trials and examine developments over time. STUDY DESIGN AND SETTING:We analyzed the statistical power in 136,212 clinical trials between 1975 and 2014 extracted from meta-analyses from the Cochrane database of systematic reviews. We determined study power to detect standardized effect sizes, where power was based on the meta-analyzed effect size. Average power, effect size, and temporal patterns were examined for all meta-analyses and a subset of significant meta-analyses. RESULTS:The number of trials with power ≥80% was low (7%) but increased over time: from 5% in 1975-1979 to 9% in 2010-2014. In significant meta-analyses, the proportion of trials with sufficient power increased from 9% to 15% in these years (median power increased from 16% to 23%). This increase was mainly due to increasing sample sizes, while effect sizes remained stable with a median Cohen's h of 0.09 (interquartile range 0.04-0.22) and a median Cohen's d of 0.20 (0.11-0.40). CONCLUSION:This study demonstrates that sufficient power in clinical trials is still problematic, although the situation is slowly improving. Our data encourage further efforts to increase statistical power in clinical trials to guarantee rigorous and reproducible evidence-based medicine.
journal_name
J Clin Epidemioljournal_title
Journal of clinical epidemiologyauthors
Lamberink HJ,Otte WM,Sinke MRT,Lakens D,Glasziou PP,Tijdink JK,Vinkers CHdoi
10.1016/j.jclinepi.2018.06.014subject
Has Abstractpub_date
2018-10-01 00:00:00pages
123-128eissn
0895-4356issn
1878-5921pii
S0895-4356(18)30140-9journal_volume
102pub_type
杂志文章abstract：OBJECTIVES:Accurately predicting hospital mortality is necessary to measure and compare patient care. External validation of predictive models is required to truly prove their utility. This study assessed the Kaiser Permanente inpatient risk adjustment methodology for hospital mortality in a patient population distinct...
journal_title：Journal of clinical epidemiology
pub_type： 杂志文章,多中心研究
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更新日期：2010-07-01 00:00:00
abstract：BACKGROUND AND OBJECTIVE:Novel cancer therapies are often approved with evidence from a single pivotal trial alone. There are concerns about the credibility of this evidence. Higher validity may be indicated by five methodological and statistical characteristics of pivotal trial evidence that were described by the U.S....
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更新日期：2019-10-01 00:00:00
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journal_title：Journal of clinical epidemiology
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journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/j.jclinepi.2018.07.007
更新日期：2018-11-01 00:00:00
abstract：:This paper reports a prospective study, carried out in elderly patients hospitalized for acute illness, designed to evaluate the effectiveness of medical treatment from the point of view of quality of life (QoL). Patient's autoperception and satisfaction with health, the most relevant subjective estimates of QoL, were...
journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/0895-4356(94)00237-k
更新日期：1995-08-01 00:00:00
abstract：:Contacts with health services like hospitals or general practitioners are usually the only available proxy measure of incidence of disease in studies based on secondary data and differential referrals or care-seeking behavior often bias such proxy measures. In former analyses based on the Occupational Hospitalization ...
journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/0895-4356(95)00554-4
更新日期：1996-07-01 00:00:00
abstract：BACKGROUND AND OBJECTIVE:Serial measurements obtained during observational longitudinal studies offer the opportunity to describe the effects of chronic diseases on patient-centered outcomes such as quality of life. The purpose of this study was to assess serial Asthma Quality of Life Questionnaire (AQLQ) and SF-36 sco...
journal_title：Journal of clinical epidemiology
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更新日期：2004-01-01 00:00:00
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journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/j.jclinepi.2016.11.003
更新日期：2017-02-01 00:00:00
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journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/s0895-4356(98)00042-0
更新日期：1998-08-01 00:00:00
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journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
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更新日期：1992-01-01 00:00:00
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journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/s0895-4356(99)00021-9
更新日期：1999-06-01 00:00:00
abstract：:The aim was to assess relationships between increased aerobic fitness sustained over 4 years, and changes in blood pressure (SBP and DBP) and lipids. Measurements were made of BP, lipids, weight, and fitness in 1000 middle-aged men and women entering a fitness programme, and were repeated 2 and 4 years later. The 342 ...
journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/0895-4356(93)90052-3
更新日期：1993-02-01 00:00:00
abstract：:Mortality rates in Denmark from ischemic heart diseases (IHD), other heart diseases and unknown causes are presented for the period 1968-92. In all age groups, mortality from IHD is higher at the beginning of the period than at the end. For other heart disease, the plot of the mortality rate is U-shaped for the age gr...
journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/0895-4356(94)00158-m
更新日期：1995-04-01 00:00:00
abstract：OBJECTIVE:In this study, we assessed the validity of maternally self-reported history of preeclampsia. STUDY DESIGN AND SETTING:This study was embedded in the Generation R Study, a population-based prospective cohort study. Data were obtained from prenatal questionnaires and one questionnaire obtained 2 months postpar...
journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/j.jclinepi.2009.10.010
更新日期：2010-08-01 00:00:00
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journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/j.jclinepi.2019.06.008
更新日期：2019-10-01 00:00:00
abstract：BACKGROUND AND OBJECTIVE:We consider the number needed to treat (NNT) when the event of interest is defined by dichotomizing a continuous response at a threshold level. If the response is measured with error, the resulting NNT is biased. We consider methods to reduce this bias. METHODS:Bias adjustment was studied usin...
journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/j.jclinepi.2004.01.021
更新日期：2004-12-01 00:00:00
abstract：OBJECTIVE:This study estimated the inter- and intraobserver reliability of a set of noninstrumented physical examination measures for knee pain in older adults. STUDY DESIGN AND SETTING:Forty-five patients from primary care, and 13 patients from secondary care, were each examined by two out of a team of three physical...
journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/j.jclinepi.2005.11.004
更新日期：2006-05-01 00:00:00
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journal_title：Journal of clinical epidemiology
pub_type： 杂志文章,多中心研究
doi：10.1016/j.jclinepi.2007.03.010
更新日期：2007-12-01 00:00:00
abstract：BACKGROUND AND OBJECTIVE:To comprehensively examine comorbidity in unselected cohorts of patients with depression, stroke, multiple sclerosis (MS), Parkinson's disease/parkinsonism (PD/PKM), dementia, migraine, and epilepsy. METHODS:This cross-sectional study used morbidity data recorded by Dutch general practitioners...
journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/j.jclinepi.2006.01.005
更新日期：2006-12-01 00:00:00
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journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/s0895-4356(96)00203-x
更新日期：1996-11-01 00:00:00
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journal_title：Journal of clinical epidemiology
pub_type： 杂志文章,评审
doi：10.1016/j.jclinepi.2012.04.012
更新日期：2013-02-01 00:00:00
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journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/j.jclinepi.2008.02.016
更新日期：2009-01-01 00:00:00
abstract：OBJECTIVES:The aim of the present study was to obtain a cross-cultural adaptation and evaluation of a Simplified Chinese (SC) version of the Tampa Scale for Kinesiophobia (TSK) for use in patients with low back pain (LBP). STUDY DESIGN AND SETTING:The TSK was translated and adapted cross-culturally following internati...
journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/j.jclinepi.2015.07.003
更新日期：2015-10-01 00:00:00
abstract：OBJECTIVES:To compare the abilities of six validated comorbidity indices (Charlson index, cumulative illness rating scale [CIRS], index of coexistent diseases, Kaplan scale, geriatrics index of comorbidity [GIC], and chronic disease score) to predict adverse hospitalization outcomes (death during hospitalization, lengt...
journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/j.jclinepi.2009.11.013
更新日期：2010-09-01 00:00:00
abstract：OBJECTIVES:If researchers want to assess reliably different aspects of general health in the migrant populations, they need translations of internationally used health assessment scales with appropriate cross-cultural adaptations and satisfactory psychometric properties. A systematic review was performed to assess the ...
journal_title：Journal of clinical epidemiology
pub_type： 杂志文章,评审
doi：10.1016/j.jclinepi.2012.12.004
更新日期：2013-06-01 00:00:00
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journal_title：Journal of clinical epidemiology
pub_type： 杂志文章,多中心研究
doi：10.1016/j.jclinepi.2018.02.018
更新日期：2018-07-01 00:00:00
abstract：:We develop a stochastic model of screening for ovarian cancer with serum levels of the CA 125 radioimmunoassay, a tumor-specific marker. The natural history of the disease is constructed using a four stage model characterized by a multivariate distribution for duration in each stage. Preserving its important features,...
journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/0895-4356(91)90075-k
更新日期：1991-01-01 00:00:00
abstract：:The purpose of this study was to assess the association between the international overweight cutoffs for children and youth and coronary heart disease risk factors. The sample included 410 boys and 337 girls 9-18 years of age from the Québec Family Study. Participants were classified as normal weight or overweight usi...
journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/s0895-4356(02)00595-4
更新日期：2003-05-01 00:00:00
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journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/j.jclinepi.2006.01.004
更新日期：2006-08-01 00:00:00
abstract：:For randomized trials that do not require prompt onset of therapy, a pre-admission preparation, called the qualification period, can deal with certain customary difficulties in design, analysis, and ethics. For the patients' baseline state, the qualification period can be used to "wash out" effects of previous treatme...
journal_title：Journal of clinical epidemiology
pub_type： 杂志文章
doi：10.1016/0895-4356(91)90208-q
更新日期：1991-01-01 00:00:00
