ALI YAHYA EZZI, AHMED YAHYA EZZI, YOUSEF AHMED ALIBISHI, NASSER MOHAMMED ALSULAIMAN, ABDULLAH MOHAMMED RAYANI, SAAD MOHAMMED ALDAWASRI, WJDAN HAMAD ALSANIE ,MOHAMMED HUSSAIN HAMDI, SALAH ALI DAWOD, IBRAHIM ABDULLAH JABOUR, MAZEN MOUSA MASMALI, SAHAR ALASMAR ALAZMI, SAAD ALI SOULAN, MOHAMMED ALI ALNAKHLI, ABDULAZIZ MOFARAH ALQAHTANI
DOI: https://doi.org/Background: C-reactive protein (CRP), particularly high-sensitivity CRP (hs-CRP), is a common blood test used as an indicator of inflammation and cardiovascular risk. Immune activation, changes in lipid metabolism, endothelial dysfunction and cardiovascular morbidity are also related to thyroid dysfunction (Ridker, 2016; Biondi & Cooper, 2008; Chaker et al., 2017). Objective: This paper reviews the scientific literature regarding the association of CRP with thyroid function tests, specifically hypothyroidism, subclinical hypothyroidism, autoimmune thyroid disease, Graves disease and subacute thyroiditis.
Methods: Peer-reviewed literature up to 2023 was tabulated and analyzed by a structured narrative synthesis. The synthesis was mainly based on the studies reporting the level of CRP or hs-CRP in relation to the level of thyroid-stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), thyroid antibodies, thyroiditis, and response to therapy. Findings: Most studies indicate that overt and subclinical hypothyroidism is accompanied by low-grade inflammation and by elevated levels of hs-CRP, but the association becomes weaker after adjustment for BMI, IR, dyslipidemia and cardiovascular risk factors (Tuzcu et al., 2005; Nagasaki et al., 2007; de Miranda et al., 2016). Marked inflammatory responses such as a high CRP and ESR are seen in all patients with subacute thyroiditis, while in autoimmune thyroid disease, the CRP findings are more variable (Pearce et al., 2003; Tang et al., 2021). Conclusion: CRP is not a thyroid specific marker, but when supplemented with thyroid function tests and clinical data, it can give clinically useful information regarding inflammatory burden and cardiometabolic risk.
The methodology of this paper is a narrative scientific review using published peer-reviewed studies that examined the association of C-reactive protein (CRP) with thyroid function tests such as thyroid-stimulating hormone (TSH), free thyroxine (FT4), and triiodothyronine (T3). Relevant articles were retrieved by searching electronic databases such as PubMed, Scopus, and Web of Science with combinations of the keywords for CRP, inflammation, hypothyroidism, hyperthyroidism, thyroiditis, and autoimmune thyroid diseases up to 2023. Studies on inflammatory markers and thyroid dysfunction in adult population were included. Data were analysed qualitatively and findings were synthesized for assessing the clinical and biological relationship between systemic inflammation and thyroidal disorders.
Conclusions: Several observational and clinical studies showed that thyroid dysfunction is associated with systemic inflammatory activation. Thyroid-related inflammatory conditions like subacute thyroiditis had significantly higher CRP levels, and elevated CRP levels were seen in patients suffering from hypothyroidism, especially subclinical hypothyroidism. A number of studies also established a linkage between abnormal TSH, metabolic dysfunction, oxidative stress and inflammatory markers. Chronic immune activation and low-grade inflammation were always associated with autoimmune thyroid diseases.
