Wide Spectrum of Thyroid Function Tests in COVID-19: From Nonthyroidal Illness to Isolated Hyperthyroxinemia

The prevalence of thyroid disorders in COVID-19 patients: a systematic review and meta-analysis

OBJECTIVES

To conduct a systematic review and meta-analysis to evaluate the prevalence of thyroid disorders in COVID-19 patients.

DATA SOURCES

Scopus, PubMed, ISI Web of Science, and Google Scholar databases were used in this review. We also consider the results of grey literature.

STUDY SELECTIONS

Cohort, cross-sectional, and case-control studies were included.

DATA EXTRACTION AND SYNTHESIS

The required data were extracted by the first author of the article and reviewed by the second author. The Pooled prevalence of outcomes of interest was applied using the meta-prop method with a pooled estimate after Freeman-Tukey Double Arcsine Transformation to stabilize the variances.

OUTCOMES AND MEASURED

The different thyroid disorders were the main outcomes of this study. The diseases include non-thyroidal illness syndrome, thyrotoxicosis, hypothyroidism, isolated elevated free T4, and isolated low free T4.

RESULTS

Eight articles were included in our meta-analysis(Total participants: 1654). The pooled prevalence of events hypothyroidism, isolated elevated FT4, isolated low FT4, NTIS, and thyrotoxicosis were estimated (Pooled P = 3%, 95% CI:2-5%, I2: 78%), (Pooled P = 2%, 95% CI: 0-4%, I2: 66%), (Pooled P = 1%, 95% CI: 0-1%, I2: 0%), (Pooled P = 26%, 95% CI: 10-42%, I2: 98%), and (Pooled P = 10%, 95% CI: 4-16%, I2: 89%), respectively.

CONCLUSION

Thyroid dysfunction is common in COVID-19 patients, with a high prevalence of non-thyroidal illness syndrome (NTIS) and thyrotoxicosis. Our meta-analysis found a 26% prevalence of NTIS and a 10% prevalence of thyrotoxicosis.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42022312601.

Thyroid Function Abnormalities and Outcomes in Hospitalized Patients with COVID-19 Infection: A Cross-Sectional Study

Thyroid gland can be affected by the COVID-19 infection. The pattern of thyroid function abnormality reported in COVID-19 is variable; in addition, some drugs used in COVID-19 patients like glucocorticoids and heparin can affect the thyroid function tests (TFT). We conducted an observational, cross-sectional study of thyroid function abnormalities with thyroid autoimmune profile in COVID-19 patients with varying severity from November 2020 to June 2021. Serum FT4, FT3, TSH, anti-TPO, and anti-Tg antibodies were measured before the initiation of treatment with steroids and anti-coagulants. A total of 271 COVID-19 patients were included in the study, of which 27 were asymptomatic and remaining 158, 39, and 47 were classified to mild, moderate and severe categories, respectively, according to MoHFW, India criteria. Their mean age was 49±17 years and 64.9% were males. Abnormal TFT was present in 37.2% (101/271) patients. Low FT3, low FT4, and low TSH were present in 21.03%, 15.9% and 4.5% of patients, respectively. Pattern corresponding to sick euthyroid syndrome was the most common. Both mean FT3 and FT3/FT4 ratio decreased with increasing severity of COVID-19 illness (p=0.001). In multivariate analysis, low FT3 was associated with increased risk of mortality (OR 12.36, 95% CI: 1.23-124.19; p=0.033). Thyroid autoantibodies were positive in 58 (27.14%) patients; but it was not associated with any thyroid dysfunction. Thyroid function abnormality is common among COVID-19 patients. Both low FT3 and FT3/FT4 ratio are indicators of disease severity while low FT3 is a prognostic marker of COVID-19 associated mortality.

Thyroxine changes in COVID-19 pandemic: A systematic review and meta-analysis

OBJECTIVE

COVID-19 infection may affect thyroid function. However, changes in thyroid function in COVID-19 patients have not been well described. This systematic review and meta-analysis assess thyroxine levels in COVID-19 patients, compared with non-COVID-19 pneumonia and healthy cohorts during the COVID-19 epidemic.

METHODS

A search was performed in English and Chinese databases from inception to August 1, 2022. The primary analysis assessed thyroid function in COVID-19 patients, comparing non-COVID-19 pneumonia and healthy cohorts. Secondary outcomes included different severity and prognoses of COVID-19 patients.

RESULTS

A total of 5873 patients were enrolled in the study. The pooled estimates of TSH and FT3 were significantly lower in patients with COVID-19 and non-COVID-19 pneumonia than in the healthy cohort (P < 0.001), whereas FT4 were significantly higher (P < 0.001). Patients with the non-severe COVID-19 showed significant higher in TSH levels than the severe (I² = 89.9%, P = 0.002) and FT3 (I² = 91.9%, P < 0.001). Standard mean differences (SMD) of TSH, FT3, and FT4 levels of survivors and non-survivors were 0.29 (P= 0.006), 1.11 (P < 0.001), and 0.22 (P < 0.001). For ICU patients, the survivors had significantly higher FT4 (SMD=0.47, P=0.003) and FT3 (SMD=0.51, P=0.001) than non-survivors.

CONCLUSIONS

Compared with the healthy cohort, COVID-19 patients showed decreased TSH and FT3 and increased FT4, similar to non-COVID-19 pneumonia. Thyroid function changes were related to the severity of COVID-19. Thyroxine levels have clinical significance for prognosis evaluation, especially FT3.