Association Between Primary Hypothyroidism and Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis

Mantovani, Alessandro; Nascimbeni, Fabio; Lonardo, Amedeo; Zoppini, Giacomo; Bonora, Enzo; Mantzoros, Christos S.; Targher, Giovanni

doi:10.1089/thy.2018.0257

Cited by 108 publications

(106 citation statements)

References 42 publications

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“…As free T4 levels drop, the risk of nonalcoholic fatty liver disease (NAFLD) increases across the spectrum of euthyroidism and hypothyroidism. (101) Conversely, NAFLD is associated with hypothyroidism. (102) TH, TH metabolites, TRβ agonists, and liver-specific analogs have been studied as potential therapeutics for treating both serum dyslipidemias and as a potential therapy for NAFLD.…”

Section: Th and Nonalcoholic Fatty Liver Diseasementioning

confidence: 99%

Thyroid Hormone Signaling and the Liver

2020

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Thyroid hormone (TH) plays a critical role in maintaining metabolic homeostasis throughout life. It is well known that the liver and thyroid are intimately linked, with TH playing important roles in de novo lipogenesis, beta‐oxidation (fatty acid oxidation), cholesterol metabolism, and carbohydrate metabolism. Indeed, patients with hypothyroidism have abnormal lipid panels with higher levels of low‐density lipoprotein levels, triglycerides (triacylglycerol; TAG), and apolipoprotein B levels. Even in euthyroid patients, lower serum‐free thyroxine levels are associated with higher total cholesterol levels, LDL, and TAG levels. In addition to abnormal serum lipids, the risk of nonalcoholic fatty liver disease (NAFLD) increases with lower free thyroxine levels. As free thyroxine rises, the risk of NAFLD is reduced. This has led to numerous animal studies and clinical trials investigating TH analogs and TH receptor agonists as potential therapies for NAFLD and hyperlipidemia. Thus, TH plays an important role in maintaining hepatic homeostasis, and this continues to be an important area of study. A review of TH action and TH actions on the liver will be presented here.

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Section: Th and Nonalcoholic Fatty Liver Diseasementioning

confidence: 99%

Thyroid Hormone Signaling and the Liver

2020

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“…Furthermore, key information errors were found in two review protocols, confusing the exposure and outcome subgroup leading to a lack of clarity [24,27]. Other errors were discovered including the fact that protocols did not provide the details of the search strategy, despite the fact that the published review [34] stated explicitly that the detailed search strategy could be found in the protocol.…”

Section: The Results Of Comparisonmentioning

confidence: 99%

Inconsistencies are common between non-Cochrane systematic reviews and their protocols registered in the International prospective register of systematic reviews (PROSPERO) but were seldom explained

Zhang

et al. 2019

Preprint

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Background: Protocols of systematic reviews allow for planning and documentation of review methods, and thus improve the transparency of reviews process. However, pre-registered a protocol is not enough, the author also need to follow it. PROSPERO is an open-access online facility for the registration of non-Cochrane systematic reviews. The purpose of our research is to determined what changed were made between non-Cochrane reviews and their protocols in PROSPERO and how likely these changes impacted the quality of systematic review. Method: In this retrospective comparative study we electronically searched for protocols and their corresponding systematic reviews in the PROSPERO platform that were “completed and published” from January to December, 2018. Two reviewers independently identified and classified changes between the protocols and systematic reviews then evaluated the impact (improve/reduce/unclear)of these change on the reporting/methodology quality of reviews. Frequency (n), percentage (%) were used to analyze the number of changes categorically in each review and the distribution of different impact caused by these changes. Results: We identified 39 pre-registered protocols and their reviews, all of which exhibited alterations. All changes to only one review are considered to improve the reporting/methodology quality, and remaining 97% of reviews (n=38) contain changes that are categorically considered to reduce the methodology/reporting quality or that have an unclear impact on reviews. Conclusions: Differences between the non-Cochrane reviews and their protocols recorded in PROSPERO are widespread, and there have been many changes having an unclear impact on the quality of reviews. Guiding the author to report and explain the differences between protocol and reviews or even requiring authors to so at the level of journal are two fundamental solutions to further improve the transparency of the non-Cochrane reviews.

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“…Furthermore, key information error was found in one review protocol (confusing the exposure and outcome [24]). We believe it's also necessary to verify these changes, as well as investigate the reasons through correspondence with the authors.…”

Section: Implications For Future Researchmentioning

confidence: 99%

Inconsistencies are common between non-Cochrane systematic reviews and their protocols registered in the International prospective register of systematic reviews (PROSPERO) but were seldom explained

Hu¹,

Zhang²,

Zhang³

et al. 2020

Preprint

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Background: Protocols of systematic reviews allow for planning and documentation of review methods and thus improve the transparency of the reviews process. However, pre-registration of a protocol is not enough, the author also need to follow it. PROSPERO is an open-access online database for the registration of non-Cochrane systematic reviews. The purpose of this study is to compare published non-Cochrane reviews with their pre-registered protocols on PROSPERO to determine what changes, if any, have been made, and how likely these changes are to impact the quality of systematic review. Methods: This is a retrospective comparative study. We searched for protocols on PROSPERO platform that were registered in 2018 and then selected the protocols that full text have been published as of January 1st 2019. Published full texts were identified through the protocol's final publication citation. Two authors independently compared and identified changes between protocols and systematic reviews and then evaluated the impact (improve, reduce, or unclear) of these changes on the reporting or methodology quality of reviews. Descriptive statistics of percentage (%) and frequency (n) were conducted. Results: We identified 39 pairs, all of which exhibited changes. “Search strategy”(92%, n=36), “data extraction”(90%, n=35), “data synthesis”(77%, n=30), “outcome”(64%, n=24), and “subgroup analysis”(64%, n=24) all showed significant changes. All changes to only one review were considered to improve the reporting or methodology quality, and the remaining 97% of reviews (n=38) contained changes that were considered to reduce the methodology or reporting quality or that had an unclear impact on systematic reviews. Conclusions: Changes between the non-Cochrane systematic reviews and their protocols recorded on PROSPERO were widespread. Some of the changes reduced the methodology or reporting quality of systematic reviews or had an unclear impact. Measures should be taken to further improve the transparency of the non-Cochrane systematic reviews. Adding a new item in updated “Preferred Reporting Items for Systematic reviews and Meta-Analyses” (PRISMA) and “Meta-analysis of Observational Studies in Epidemiology” (MOOSE) to guide reporting and explaining the changes, as well as advising peer reviewers (and editors) to check the reviews against the protocols are two suggested fundamental solutions.

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Association Between Primary Hypothyroidism and Nonalcoholic Fatty Liver Disease: A Systematic Review and Meta-Analysis

Abstract: This large and updated meta-analysis shows that the presence of variably defined hypothyroidism is significantly associated with the presence and severity of NAFLD. However, the observational design of the eligible studies does not allow for proving causality.

Cited by 108 publications

References 42 publications

Thyroid Hormone Signaling and the Liver

Thyroid Hormone Signaling and the Liver

Inconsistencies are common between non-Cochrane systematic reviews and their protocols registered in the International prospective register of systematic reviews (PROSPERO) but were seldom explained

Inconsistencies are common between non-Cochrane systematic reviews and their protocols registered in the International prospective register of systematic reviews (PROSPERO) but were seldom explained

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