Observational studies often make clinical practice recommendations: an empirical evaluation of authors' attitudes

Prasad, Vinay; Jorgenson, Joel; Ioannidis, John P. A.; Cifu, Adam S.

doi:10.1016/j.jclinepi.2012.11.005

Cited by 68 publications

(45 citation statements)

References 31 publications

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“…We further determined whether each article was an RCT or an observational study (defined as an original study that is not an RCT, meta-analysis, decision or cost-effectiveness analysis, or a study whose main data were derived from modeling - a definition used in prior empirical work) [11]. A five-point study design rating system was also adapted based on the United States Preventive Services Task Force (USPSTF) hierarchy of evidence criteria [12].…”

Section: Methodsmentioning

confidence: 99%

Media Coverage of Medical Journals: Do the Best Articles Make the News?

2014

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Section: Methodsmentioning

confidence: 99%

Media Coverage of Medical Journals: Do the Best Articles Make the News?

2014

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“…Therefore, one might argue that its use should not be recommended, but recommendations are frequently based on observational studies, at least in distinguished general medicine journals. 23 Although nearly half of our study population had late HAT, we did not find any clear factors that might reflect poor patient outcomes. Late HAT, however, played something of a role in 1 patient's graft loss long after LT (shortly after MRI), and this emphasizes the importance of vigilant observation.…”

Section: Discussionmentioning

confidence: 57%

“…The benefits and risks of ASA in reducing HAT after LT have not been studied to our knowledge in randomized controlled trials. Therefore, one might argue that its use should not be recommended, but recommendations are frequently based on observational studies, at least in distinguished general medicine journals …”

Section: Discussionmentioning

confidence: 99%

Late hepatic artery thrombosis after pediatric liver transplantation: A cross-sectional study of 34 patients

et al. 2014

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Hepatic artery thrombosis (HAT) after liver transplantation (LT) increases patient morbidity and mortality. Early HAT is considered to occur within the first month after LT, whereas late HAT occurs after the first month. Few studies have addressed late HAT after LT, especially in pediatric patients. Between 1987 and 2007, 99 patients (age < 18 years) underwent deceased donor LT. Thirty-four of 66 eligible patients (52%) underwent magnetic resonance imaging (MRI) according to protocol. On the basis of MRI findings, the patients were grouped as those who experienced late HAT and those who did not. Additionally, potential risk factors for late HAT were analyzed retrospectively. P values were adjusted for multiplicity. The median age at LT was 1.7 years [interquartile range (IQR) 5 1.0-9.6 years], and the median follow-up time at MRI was 9.5 years (IQR 5 4.0-16.4 years). Late HAT was diagnosed in 15 of the 34 patients [44%, 95% confidence interval (CI) 5 29%-61%] undergoing MRI and in 3 of these patients with angiography preceding MRI. Ultrasonography revealed late HAT in 6 of these 15 patients with a sensitivity of 40% (95% CI 5 20%-64%). The donor/recipient weight ratio remained significantly higher for the patients with late HAT versus the patients without late HAT after P values were adjusted (5.4 versus 1.9, P 5 0.03). No marked differences were observed in laboratory or liver histology parameters between the groups. In conclusion, late HAT is common after pediatric LT. The donor/recipient weight ratio was higher for patients with late HAT, and this was attributable to the lower weight of the recipients. No salient features of late HAT were observed with respect to laboratory or histological parameters, at least in terms of our study's cross-sectional period. Liver Transpl 20:591-600, 2014. V C 2014 AASLD.Received October 22, 2013; accepted January 30, 2014. See Editorial on Page 512Vascular complications after liver transplantation (LT) decrease both graft and patient survival.1 Hepatic artery thrombosis (HAT) is a major cause of retransplantation in the pediatric population.2 Early and late forms of HAT have been described, but the exact time interval for these 2 forms has not been established. However, most studies define early HAT as occurring within the first month after LT. 3The incidence of early HAT is higher in pediatric patients versus adult patients, and risk factors for early HAT have been proposed even in a contradictory manner.3 For example, in the setting of pediatric LT,

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“…Despite the large volume of reports on leptin and AD, it is important to recognize that all observational studies are subject to unmeasured confounding and, because of this potential for bias, cannot solely be relied upon for evidence [20] . Oftentimes, only randomized controlled trials can elucidate this bias and, in some cases, may reveal completely different findings.…”

Section: Introductionmentioning

confidence: 99%

Examining the Causal Role of Leptin in Alzheimer Disease: A Mendelian Randomization Study

Romo¹,

Schooling²

2017

Neuroendocrinology

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Background: Observational evidence regarding the role of leptin in Alzheimer disease (AD) is conflicting. We sought to determine the causal role of circulating leptin and soluble plasma leptin receptor (sOB-R) levels in AD using a separate-sample Mendelian randomization study. Methods: Single nucleotide polymorphisms (SNPs) independently and solely predictive of log-transformed leptin (rs10487505 [LEP], rs780093 [GCKR], rs900400 [CCNL1], rs6071166 [SLC32A1], and rs6738627 [COBLL1]) and of sOB-R (rs1137101 [LEPR], rs2767485 [LEPR], and rs1751492 [LEPR]) levels (ng/mL) were obtained from 2 previously reported genome-wide association studies. We obtained associations of leptin and sOB-R levels with AD using inverse variance weighting with fixed effects by combining Wald estimates for each SNP. Sensitivity analyses included using weighted median and MR-Egger methods and repeating the analyses using only SNPs of genome-wide significance. Results: Using inverse variance weighting, genetically predicted circulating leptin levels were not associated with AD, albeit with wide confidence intervals (CIs): odds ratio (OR) 0.99 per log-transformed ng/mL; 95% CI 0.55-1.78. Similarly, the association of sOB-R with AD was null using inverse variance weighting (OR 1.08 per log-transformed ng/mL; 95% CI 0.83-1.41). Results from our sensitivity analyses confirmed our findings. Conclusions: In this first Mendelian randomization study estimating the causal effect of leptin on AD, we did not find an effect of genetically predicted circulating leptin and sOB-R levels on AD. As such, this study suggests that leptin is unlikely to be a major contributor to AD, although the wide CIs preclude a definitive assessment.

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Observational studies often make clinical practice recommendations: an empirical evaluation of authors' attitudes

Cited by 68 publications

References 31 publications

Media Coverage of Medical Journals: Do the Best Articles Make the News?

Media Coverage of Medical Journals: Do the Best Articles Make the News?

Late hepatic artery thrombosis after pediatric liver transplantation: A cross-sectional study of 34 patients

Examining the Causal Role of Leptin in Alzheimer Disease: A Mendelian Randomization Study

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