Meta-analysis on the Association Between Thyroid Hormone Disorders and Arterial Stiffness

Figures

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  Figure 1.. Stepwise procedure for study selection.

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  Figure 2.. Bias assessment of selected studies. Risk of bias was classified as low (green), moderate (yellow), high (red), or critical (brown). Risk of bias was based on the judgement of domains D1-D7. Risk of bias in D1 was judged moderate for Chen et al and Peixoto de Miranda et al as they included patients with hypertension and diabetes, and critical for Feng et al. because of all the missing data. Risk of bias in D2 was judged moderate for Chen et al, because free thyroxine levels were not specified, and Feng et al. because the exact mean value of TSH and free thyroxine were not specified. Risk of bias in D5 was judged moderate for Tudoran et al and Tanriverdi et al (both did not report blood pressure), as well as Yildiz et al (not reporting cholesterol). Risk of bias in D5 was judged high for Chen et al not reporting the exact proportion of females and mean free thyroxine levels, and critical for Feng et al not reporting almost all variables linked to cardiovascular risk profile. It has to be noted that even if Kang et al did not report mean cholesterol levels, they stated that patients with hyperlipidemia were excluded. Risk of bias in D6 was judged moderate when PWV was assessed at…

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  Figure 3.. Arterial stiffness in patients with hypothyroidism. (A) Forest plot indicating the effect of hypothyroidism on PWV compared with controls. (B) Leave-one-out method showing the effect of sequential omission of individual studies on pooled MD. (C) Forest plot with subgroup analysis indicating the effect of overt hypothyroidism and subclinical hypothyroidism on PWV as compared to controls. Peixoto de Miranda 2016 [19]; Chen 2010a [18]; Tudoran 2015a and Tudoran 2015c [41]; Tanriverdi 2019 [43]; Mousa 2020a and Mousa 2020b [42]; Feng 2016a [20]; Tudoran 2015b [41]; Nagasaki 2009b and Nagasaki 2009a [29]; Nagasaki 2007 [28].

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  Figure 4.. Meta-regression analysis in patients with hypothyroidism. (A) Bubble plot representing the correlation between age and mean difference of PWV. (B) Forest plot with subgroup analysis indicating the effect of hypothyroidism on PWV, as assessed by carotid-femoral or carotid-radial PWV (group A = central stiffness), brachial-ankle PWV (group B = central-peripheral stiffness), ultrasonography (group C = central stiffness by ultrasound). Peixoto de Miranda 2016 [19]; Tudoran 2015a and Tudoran 2015c [41]; Tanriverdi 2019 [43]; Tudoran 2015b [41]; Chen 2010a [18]; Nagasaki 2009b and Nagasaki 2009a [29]; Nagasaki 2007 [28]; Mousa 2020a and Mousa 2020b [42]; Feng 2016a [20].

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  Figure 5.. Funnel plot of the studies evaluating PWV in patients with hypothyroidism.

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  Figure 6.. Arterial stiffness in patients with thyrotoxicosis. (A) Forest plot indicating the effect of thyrotoxicosis on PWV compared with controls. (B) Influence analysis of the studies evaluating the effects of thyrotoxicosis on PWV. Outliers and influential cases are displayed in red color. Che is for Chen et al, Fen is for Feng et al, Gro is for Grove-Laugese et al, Kan is for Kang et al, Yil is for Yildiz et al. (C) Leave-one-out method showing the effect of sequential omission of individual studies on pooled MD. (D) Forest plot indicating the effect of thyrotoxicosis on PWV after omitting influential studies.