Interferon-induced thyroid dysfunction in chronic hepatitis C

A systematic review and meta-analysis of endocrine-related adverse events associated with interferon

OBJECTIVES

To perform a systematic review and meta-analysis of interferon and endocrine side effects, including their incidence, evaluation, and management.

METHODS

PubMed was searched through March 7th, 2021, by 2 authors independently (LH Wang and H Zhao). Early phase I/II, phase III experimental trials, prospective and retrospective observational studies were included. Stata 16.0 (StataCorp LLC, 16.0) was the main statistical software for meta-analysis. The weighted incidence and risk ratio were estimated for primary thyroid disease and diabetes mellitus.

RESULTS

A total of 108 studies involving 46265 patients were included. Hypothyroidism was the most common thyroid disorder, followed by hyperthyroidism. IFN α+RBV treated patients experienced hypothyroidism in 7.8% (95%CI, 5.9-9.9), which was higher than IFN α (5.2%; 95%CI, 3.7-6.8) and IFN β (7.0%; 95%CI, 0.06-23.92). IFN α+RBV treated patients experienced hyperthyroidism in 5.0% (95%CI, 3.6-6.5), which was higher than IFN α (3.5%; 95%CI, 2.5-4.8) and IFN β (3.4%; 95%CI, 0.9-7.5). The summary estimated incidence of painless thyroiditis was 5.8% (95%CI, 2.8-9.8) for IFN α, and 3.5% (95%CI,1.9-5.5) for IFN α+RBV. The summary estimated incidence of diabetes was 1.4% (95%CI, 0.3-3.1) for IFN, 0.55% (95%CI, 0.05-1.57) for IFN α, 3.3% (95%CI,1.1-6.6) for IFN α+RBV.

CONCLUSIONS

Our meta-analysis shows a high incidence of endocrine adverse events provoked by IFN, further reinforced by combined RBV treatment.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/, identifier CRD42022334131.

Graves' disease: Epidemiology, genetic and environmental risk factors and viruses

Graves' disease (GD) is the most common cause of hyperthyroidism in developed Countries. It is more common between 30 and 60 years; 5-10 times more frequent in women. The genetic predisposition accounts for 79% of the risk for GD, while environmental factors for 21%. About 70% of genes associated with autoimmune thyroid disorders (AITD) are implicated in T-cell function. Among GD endogenous factors, estrogens, X-inactivation and microchimerism are important. Among environmental risk factors, smoking, iodine excess, selenium and vitamin D deficiency, and the occupational exposure to Agent Orange have been associated with GD. Many studies showed that HCV is associated with thyroid autoimmunity and hypothyroidism, in patients with chronic HCV hepatitis (CHC); a significant link has been shown also between HCV-related mixed cryoglobulinemia and risk for GD. Moreover, IFN-α-treated CHC patients develop GD more frequently. Novel studies are needed about possible risk factors to reduce the occurence of GD in West Countries.

Long-term outcomes and risk factors of thyroid dysfunction during pegylated interferon and ribavirin treatment in patients with chronic hepatitis C infection in Taiwan

BACKGROUND

This study aimed to investigate the occurrence and risk factors of thyroid dysfunction (TD) in patients with chronic hepatitis C (CHC) infection in Taiwan.

METHODS

The data in this study were obtained from the Taiwan National Health Insurance Research (Taiwan NHIR) database between 2001 and 2013. CHC patients treated with pegylated interferon/ribavirin (PEG-IFN/RBV) were enrolled as case patients, and nontreated CHC patients were enrolled as controls and were matched at a control:case ratio of 3:1 by index date, age (± 3 years), and sex. We compared the cumulative incidence of TD between the cohorts at follow-up until 2013.

RESULTS

During the study period, 3810 cases and 9393 controls were included in the study. Among the study subjects, 173 (4.5%) case patients and 244 (2.6%) controls were diagnosed with TD during the follow-up period. The types of TD were hypothyroidism (42.9%), hyperthyroidism (31.2%), and thyroiditis (25.9%). Compared to controls during the 13-year follow-up, patients treated with PEG-IFN/RBV had a higher incidence rate of TD (P < 0.0001), as determined using the Kaplan-Meier method. Cox proportional hazards regression analysis showed that female sex (adjusted hazard ratio (HR): 1.49; 95% confidence interval (CI): 1.23-1.75; P < 0.001), treatment with PEG-IFN/RBV (HR: 1.68; 95% CI: 1.38-2.06; P < 0.001), hyperlipidemia (HR: 1.38; 95% CI: 1.12-1.71; P < 0.001), and past history of goiter (HR: 6.40; 95% CI: 5.00-8.18; P < 0.001) were independent predictors for the development of TD.

CONCLUSIONS

PEG-IFN/RBV treatment may be an independent risk factor for thyroid dysfunction among patients with hepatitis C virus (HCV) infection. Monitoring thyroid function keenly during PEG-IFN/RBV therapy in patients with chronic HCV infection is recommended for clinicians, especially for female patients and for patients with a history of hyperlipidemia and goiter.

Incidence of and risk factors for thyroid dysfunction during peginterferon α and ribavirin treatment in patients with chronic hepatitis C

BACKGROUND/AIMS

Thyroid dysfunction (TD) is more likely to occur in patients with chronic hepatitis C (CHC) and is particularly associated with interferon (IFN) treatment. The purpose of this study was to investigate the incidence, outcomes, and risk factors for TD during pegylated interferon (PEG-IFN) and ribavirin (RBV) combined therapy in patients with CHC.

METHODS

A total of 242 euthyroid patients with CHC treated with PEG-IFN/RBV were included. Thyroid function and autoantibodies were measured at baseline, and virologic response and thyroid function were assessed every 3 months during therapy.

RESULTS

TD developed in 67 patients (27.7%) during the PEG-IFN/RBV treatment. The types of TD were subclinical hypothyroidism (50.7%), hypothyroidism (14.9%), thyroiditis (11.9%), subclinical hyperthyroidism (10.4%), and hyperthyroidism (10.4%). Most of the patients with TD recovered spontaneously; however, seven patients (10.4%) needed thyroid treatment. The sustained virological response rate was higher in patients with TD than those without (65.7% vs. 49.1%, p = 0.02). Baseline thyroid stimulating hormone (TSH) concentrations (odds ratio [OR], 2.09; 95% confidence interval [CI], 1.96 to 8.77; p < 0.001), presence of the thyroid peroxidase antibody (OR, 8.81; 95% CI, 1.74 to 44.6; p = 0.009), and PEG-IFNα-2b (OR, 3.01; 95% CI, 1.43 to 6.39; p = 0.004) were independent risk factors for the development of TD.

CONCLUSIONS

TD developed in 27.7% of patients with CHC during PEG-IFN/RBV treatment, and 10.4% of these patients needed thyroid treatment. TD is associated with a favorable virologic response to PEG-IFN/RBV. Assessment of TSH and thyroid autoantibodies at baseline and close monitoring of thyroid function during PEG-IFN/RBV therapy are necessary for early detection and management of IFN-induced TD.

Thyroid dysfunction in Chinese hepatitis C patients: Prevalence and correlation with TPOAb and CXCL10

AIM: To investigate the relationship among pretreatment serum CXC chemokine ligand 10 (CXCL10), thyroid peroxidase antibody (TPOAb) levels and thyroid dysfunction (TD) in Chinese hepatitis C patients.

METHODS: One hundred and thirty-nine treatment-naive genotype 1 chronic hepatitis C patients with no history of TD or treatment with thyroid hormones were enrolled in this study. Patients underwent peginterferon alfa-2a/ribavirin (PegIFNα-2a/RBV) treatment for 48 wk, followed by detection of clinical factors at each follow-up point. Hepatitis C virus (HCV) antibodies were analyzed using microsomal chemiluminescence, and serum HCV RNA was measured by real-time PCR assay at 0, 4, 12, 24 and 48 wk after the initiation of therapy and 24 wk after the end of therapy. To assess thyroid function, serum thyroid stimulating hormone (TSH), free thyroxine (FT4), free triodothyronine (FT3) and TPOAb/thyroglobulin antibody (TGAb) levels were determined using chemiluminescent immunoassays every 3 mo. Serum CXCL10 levels were determined at baseline.

RESULTS: The prevalence of TD was 18.0%. Twenty-one (84.0%) out of twenty-five patients exhibited normal thyroid function at week 24 after therapy. The rate of sustained virological response to PegIFNα-2a/RBV in our study was 59.0% (82/139), independent of thyroid function. Pretreatment serum CXCL10 levels were significantly increased in patients with euthyroid status compared with patients with TD (495.2 ± 244.2 pg/mL vs 310.0 ± 163.4 pg/mL, P = 0.012). Patients with TD were more frequently TPOAb-positive than non-TD (NTD) patients (24.2% vs 12.3%, P = 0.047) at baseline. Three of the one hundred and fifteen patients without TPOAb at baseline developed TD at the end of treatment (37.5% vs 2.6%, P = 0.000). Female patients exhibited an increased risk for developing TD compared with male patients (P = 0.014).

CONCLUSION: Lower pretreatment serum CXCL10 levels are associated with TD, and TD prevalence increases in female patients and patients who are positive for TPOAb at baseline.

Patterns of interferon-alpha-induced thyroid dysfunction vary with ethnicity, sex, smoking status, and pretreatment thyrotropin in an international cohort of patients treated for hepatitis C

BACKGROUND

Interferon-alpha (IFNα)-induced thyroid dysfunction occurs in up to 20% of patients undergoing therapy for hepatitis C. The diversity of thyroid disease presentations suggests that several different pathological mechanisms are involved, such as autoimmunity and direct toxicity. Elucidating the relationships between risk factors and disease phenotype provides insight into the mechanisms of disease pathophysiology.

METHODS

We studied 869 euthyroid patients from the ACHIEVE 2/3 trial, a randomized international clinical trial comparing pegylated-IFNα2a weekly or albumin-IFNα2b every 2 weeks for up to 24 weeks in patients with hepatitis C, genotype 2 or 3, from 136 centers. The study population was 60% male and 55% white. Serum thyrotropin (TSH) and free thyroxine were measured before therapy, monthly during treatment from week 8, and at 4- and 12-week follow-up visits.

RESULTS

Overall, 181 (20.8%) participants had at least one abnormal TSH during the study. Low TSH occurred in 71 (8.2%), of whom 30 (3.5%) had a suppressed TSH below 0.1 mU/L. Hypothyroidism occurred in 53 patients (6.1%), with peak TSH above 10 mU/L in 12 patients (1.4%). Fifty-seven patients had a biphasic thyroiditis (6.6%), with extreme values for the nadir and/or peak TSH in all but one. Medical therapy was given to one thyrotoxic patient, four hypothyroid patients, and 26 biphasic thyroiditis patients. Multivariate logistic regression analysis demonstrated that biphasic thyroiditis is associated with being female and higher pretreatment serum TSH, whereas being Asian or a current smoker decreased the risk of thyroiditis. Hypo- and hyperthyroidism are most strongly predicted by the pretreatment TSH.

CONCLUSIONS

Biphasic thyroiditis accounted for the majority (58%) of clinically relevant IFNα-induced thyroid dysfunction. We confirmed our recent findings in a related cohort that female sex is a risk factor for thyroiditis but not hypothyroidism. Further, in this large multiethnic study, the risk of thyroiditis is dramatically increased, specifically for white women. Smoking was found to be protective of thyroiditis. These results support closer monitoring of women and those with a serum TSH at the extremes of the normal range during therapy so that prompt intervention can mitigate the consequences of thyroid dysfunction associated with IFNα treatment.

Systematic review: Asian patients with chronic hepatitis C infection

BACKGROUND

Chronic hepatitis C (CHC) infection is a risk factor for both the development of end-stage liver disease and hepatocellular carcinoma (HCC). Globally, approximately 170 million people are chronically infected with the hepatitis C virus (HCV), and the majority of these individuals come from the western Pacific and Southeast Asia regions (94.6 million persons combined). CHC is an understudied and underappreciated health problem in many Asian countries and in the US, where Asians represent one of the fastest growing groups of new Americans.

AIM

To perform a systematic review of the current literature on the epidemiology, diagnosis and screening, clinical characteristics and response to anti-viral therapy of Asians with CHC.

METHODS

Using a PubMed search of 'hepatitis C' and 'Asia,' 341 original manuscripts published in peer-reviewed journals were identified, and 99 were selected based on their relevance.

RESULTS

Many Asian CHC patients do not have easily identifiable risk factors and may be underdiagnosed. Rates of HCV infection in Asians on community screening in the US are unexpectedly high, and there is a high prevalence of HCV genotype 6 in Southeast Asia and Southern China. HCV-infected Asians tend to present at older age and may have higher risk of HCC; however, they respond better to anti-viral therapy than non-Asians across all HCV genotypes.

CONCLUSIONS

Given the high HCV endemicity in Asia, lack of identifiable risk factors and favourable treatment response rates in Asians, we advocate the screening for HCV infection of all Asians who come from areas where HCV prevalence is ≥2%.

Autoantibodies and autoimmune disease during treatment of children with chronic hepatitis C

OBJECTIVES

Autoantibodies were studied in a well-characterized cohort of children with chronic hepatitis C during treatment with pegylated interferon and ribavirin to assess the relation with treatment and development of autoimmune disease.

METHODS

: A total of 114 children (5-17 years), screened for the presence of high-titer autoantibodies, were randomized to pegylated interferon with or without ribavirin. Anti-nuclear, anti-liver-kidney-microsomal, anti-thyroglobulin, anti-thyroid peroxidase, insulin, anti-glutamic acid decarboxylase (GAD) antibodies were measured after trial completion using frozen sera.

RESULTS

At baseline, 19% had autoantibodies: anti-nuclear antibodies (8%), anti-liver-kidney-microsomal antibodies (4%), and glutamic acid decarboxylase antibodies (4%). At 24 and 72 weeks (24 weeks after treatment completion), 23% and 26% had autoantibodies (P=0.50, 0.48 compared with baseline). One child developed diabetes and 2 hypothyroidism during treatment; none developed autoimmune hepatitis. At 24 weeks, the incidence of flu-like symptoms, gastrointestinal symptoms, and headaches was 42%, 8% and 19% in those with autoantibodies versus 52%, 17%, and 26% in those without (P=0.18, 0.36, and 0.20, respectively). In children with negative hepatitis C virus polymerase chain reaction at 24 weeks, there was no difference in the rate of early virologic response/sustained virologic response, respectively, in those with autoantibodies 76%/69% vs 58%/65% in those without (P=0.48).

CONCLUSIONS

Despite screening, we found autoantibodies commonly at baseline, during treatment for chronic hepatitis C and after. The presence of antibodies did not correlate with viral response, adverse effects, or autoimmune hepatitis. Neither screening nor archived samples assayed for thyroid and diabetes-related antibodies identified the 3 subjects who developed overt autoimmune disease, diabetes (1), and hypothyroidism (2).

Thyroid disease in chronic hepatitis C infection treated with combination interferon-α and ribavirin: management strategies and future perspective

OBJECTIVE

Hepatitis C virus (HCV) infection is one of the major epidemics afflicting young people in both developed and developing countries. The most common endocrine disorder associated with this infection, especially in conjunction with interferon-α (IFN-α)-based therapy, is thyroid disease (TD). This review examines the development of TD before, during, and after the completion of treatment with combination IFN-α and ribavirin (RBV) for chronic HCV infection. We also summarize the current understanding of the natural history of the condition and propose management and follow-up guidelines.

METHODS

PubMed was searched up to June 30, 2011 for English-language publications that contained the search terms "hepatitis C virus," "chronic hepatitis C," "HCV," "thyroid disease," "thyroiditis," "autoimmunity," "interferon-alpha," and "ribavirin." Additional publications were identified from the reference lists of identified papers. The included studies were original research publications and included combination IFN-α and RBV use in patients that developed TD.

RESULTS

The prevalence of TD before combination IFN-α and RBV therapy ranges from 4.6 to 21.3%; during therapy, 1.1 to 21.3%; and after therapy, 6.7 to 21.3%. The most common TD is thyroiditis. Thyroid function testing (TFT) frequency and diagnostic criteria for various thyroid conditions are not standardized, and many of the existing studies are retrospective.

CONCLUSION

Patients undergoing this therapy should be assessed with a standardized protocol to appropriately detect and manage developed TD. Based on the currently available literature, we recommend that patients receiving combination interferon-α and RBV therapy undergo monthly thyrotropin (TSH) level testing.

Frequency of thyroid dysfunctions during interferon alpha treatment of single and combination therapy in hepatitis C virus-infected patients: a systematic review based analysis

BACKGROUND

Thyroid dysfunction is the commonest endocrinopathy associated with HCV infection due to interferon-based treatment. This comprehensive and systematic review presents the available evidence for newly developed thyroid antibodies and dysfunctions during interferon treatment (both single and combination) in HCV patients.

METHODOLOGY/PRINCIPAL FINDINGS

This systematic review was conducted in accordance with the PRISMA guidelines. The data generated were used to analyze the risk for thyroid dysfunctions during interferon (IFN) treatment in HCV patients. There was a wide range in the incidence of newly developed thyroid dysfunctions and thyroid antibodies in HCV patients during IFN treatment (both single and combination). The wide range of incidence also denoted the possibility of factors other than IFN treatment for thyroid-related abnormalities in HCV patients. These other factors include HCV viral factors, genetic predisposition, environmental factors, and patho-physiological factors. Variations in IFN dosage, treatment duration of IFN, definition/criteria followed in each study for thyroid dysfunction and irregular thyroid function testing during treatment in different studies influence the outcome of the single studies and jeopardise the validity of a pooled risk estimate of side effects of thyroid dysfunction. Importantly, reports differ as to whether the thyroid-related side effects disappear totally after withdrawal of the IFN treatment.

CONCLUSIONS/SIGNIFICANCE

The present review shows that there is a wide range in the incidence of newly developed thyroid dysfunctions and thyroid antibodies in IFN treated HCV patients. This is a comprehensive attempt to collate relevant data from 56 publications across several nations about IFN (both mono and combination therapy) related thyroid dysfunction among HCV patients. The role of each factor in causing thyroid dysfunctions in HCV patients treated with IFN should be analyzed in detail in future studies, for a better understanding of the problem and sounder clinical management of the disease.

Thyroid dysfunction in chinese patients with chronic hepatitis C treated with interferon alpha: incidence, long-term outcome and predictive factors

BACKGROUND

Thyroid dysfunction (TD) represents an extra-hepatic manifestation of chronic hepatitis C (CHC) and it may also be a side effect of interferon-alpha (IFN-α) based treatment. However, previous studies have shown a wide variation in the incidence of TD in patients with CHC. Furthermore, the long-term outcomes and the predictive factors of TD in patients who receive IFN-α based treatment have still not been fully studied.

OBJECTIVES

The purpose of this study was to describe the incidence and long-term outcomes of TD in Chinese patients with CHC receiving IFN-αbased treatment. We also aimed to identify the predictive factors of TD associated with this type of therapy.

PATIENTS AND METHODS

A retrospective case-series study of 592 consecutive CHC patients with normal baseline thyroid functions, who received IFN-αbased therapy, was performed. Thyroid function was assessed at baseline and every three months during treatment, as well as in the follow-up after cessation of therapy. The incidence and long-term outcomes of TD were observed. The prevalence of pretreatment thyroid peroxidase antibodies (TPOAb) were assayed in a sex- and age-matched nested case-control study. Multivariable stepwise regression analysis was used to explore the independent effects of the baseline factors, on the incidence of TD.

RESULTS

At the end of the IFN-αbased therapy, 68 patients (11.5%) in the study had developed TD, 58 patients (85.3%) presented with subclinical TD, and only 10 patients (14.7%) developed overt thyroiditis. The thyroid function of 46 patients (67.8%) spontaneously returned to normal in the six months of follow-up and only three patients (4.4%) had persistent overt TD symptoms after the 24 month follow-up period. Multivariate stepwise analysis suggested that gender and pretreatment TPOAb were the independent factors related to the incidence of TD. Both female patients (OR, 4.31; 95%CI, 2.06-7.31; P = 1.26×10-4) and participants with a positive pretreatment TPOAb (OR = 3.9, 95%CI, 1.72-8.54, P = 0.008) had an increased risk for the development of TD.

CONCLUSIONS

The incidence of TD in Chinese patients with CHC during IFN-αbased therapy was 11.5%, the majority of which was subclinical, while only a very small group had long-term overt TD requiring ongoing medical therapy. Female gender and pretreatment TPOAb positivity are risk factors for the development of TD during IFN-αbased therapy.

Thyroid dysfunction in Turkish patients with chronic hepatitis C receiving peginterferon plus ribavirin in the period of 2005-2010

Interferon-α based therapy for chronic hepatitis C (CHC) is associated with thyroiditis and thyroid dysfunction (TD). This study investigated whether TD during pegylated interferon-α (PEG-IFN) plus ribavirin treatment favors sustained viral response (SVR), and also the association between TD and PEG-IFN formulations. This retrospective study was performed in CHC patients who had received PEG-IFN plus ribavirin and had been followed for six months after treatment. Several factors were compared between patients with and without TD. 119 patients were included in the study. De novo incidence of TD was found to be 16.8%, and 16 of the 18 patients with TD achieved SVR. Although this rate was higher than patients without TD according to univariate analysis, logistic regression analysis revealed that there was not a significant association between TD and SVR, whereas baseline thyroperoxidase antibody (anti-TPO) positivity was the only significant predictor of TD. Moreover, TD was not associated with PEG-IFN type. Both interferon-α and hepatitis C virus (HCV) contribute to TD during antiviral therapy. It seems that there is no association between thyroid toxicity and viral clearance or type of PEG-IFN; however, anti-TPO positivity before treatment is the strongest predictor for TD during antiviral therapy.

Phenotypes of interferon-α-induced thyroid dysfunction among patients treated for hepatitis C are associated with pretreatment serum TSH and female sex

CONTEXT

Thyroid dysfunction is a common complication of interferon-α (IFNα) therapy, with many phenotypic patterns and the potential for significant morbidity.

OBJECTIVE

Our objective was to gain mechanistic insight and predict clinical presentations by determining the risk factors for distinct subtypes of IFNα-induced thyroid dysfunction.

DESIGN

ACHIEVE-1, a randomized trial conducted from 2005-2009, compared long-acting preparations of IFNα in 1323 patients with hepatitis C, genotype 1.

SETTING

A total of 149 outpatient clinics in North America, Europe, and Australia participated.

PATIENTS

We studied 1233 patients who were euthyroid at baseline. This population is 60% male and 82% Caucasian.

INTERVENTIONS

Patients were treated with pegylated IFNα2a weekly or albumin-IFNα2b every 2 wk for 48 wk. Serum TSH and free T(4) were measured before therapy and 12 or more times over 60 weeks.

MAIN OUTCOME MEASURES

Thyroid dysfunction was defined as a TSH outside the normal range during the course of therapy. Low serum TSH indicated thyrotoxicosis, elevated TSH indicated hypothyroidism, and both abnormalities occurred in biphasic thyroiditis.

RESULTS

Of previously euthyroid patients, 16.7% developed abnormal TSH values during therapy, including 24 with TSH below 0.1 mU/liter, 69 with TSH over 5.5 mU/liter, and 76 with biphasic thyroiditis. Biphasic thyroiditis was over 8-fold more common among women than men using multivariate logistic regression analysis [odds ratio (OR) = 8.4; 95% confidence interval (CI) = 4.5-15.8]. Thyrotoxicosis was most strongly associated with a lower pretreatment TSH (OR = 4.1 per -1 mU/liter decline; 95% CI = 1.9-9), whereas hypothyroidism was strongly associated with higher pretreatment TSH (OR = 3.9 per 1 mU/liter increase; 95% CI = 3-5.2).

CONCLUSIONS

Biphasic thyroiditis is common among women treated for hepatitis C with IFNα. Lower and higher pretreatment serum TSH are associated with greater likelihood of thyrotoxicosis and hypothyroidism, respectively. Antithyroid antibody levels were not available for the cohort, and thus we cannot clarify the role of pretreatment thyroid autoimmunity as a risk factor. Our results do show that readily identifiable patient characteristics are risk factors for specific patterns of IFN-induced thyroid dysfunction. These findings suggest that distinct mechanisms may underlie subtypes of thyroid dysfunction associated with immune-modulatory therapy for hepatitis C.

Thyroid autoantibodies and dysfunction do not impact the treatment efficacy of peginterferon and ribavirin combination therapy in chronic hepatitis C

AIMS

Thyroid disorders, such as the emergence of thyroid autoantibodies (TAs) and thyroid dysfunction (TD), are not uncommon in chronic hepatitis C (CHC) patients. The study aimed to investigate the impact of TAs and dysfunction on the treatment response to pegylated interferon-α plus ribavirin (PegIFN/RBV) combination therapy in CHC patients. The association between interleukin-28B (IL-28B) genetic variants and occurrence of TAs and dysfunction was also analyzed.

METHODS

A total of 449 treatment-naive Taiwanese CHC patients with euthyroid status were consecutively enrolled. They received PegIFN/RBV combination therapy with current recommendation. TAs, TD, and IL-28B genetic variants were measured before treatment. Monitoring of TD was done at 3-month intervals during treatment, at end of treatment, and at end of follow-up (EOF).

RESULTS

The development of TAs was detected in 42 (9.4%) patients before treatment, and the incidence of TD during or at EOF was 20%. Of 287 patients with IL-28B rs8099917 TT genotype, 29 (10.1%) had TAs before treatment, whereas the patients with other genotypes did not have TAs (P = 0.04). There was no significant difference of TD incidence during treatment or at EOF between the patients with different IL-28B genotypes. There was also no significant difference of sustained virologic response according to the presence of TAs, TD, or different manifestations of TD.

CONCLUSION

Taiwanese CHC patients with rs8099917 TT genotype had a higher incidence of TAs. The development of TAs and TD did not impact the treatment efficacy of PegIFN/RBV combination therapy.

The natural history of interferon-α induced thyroiditis in chronic hepatitis c patients: a long term study

BACKGROUND

Autoimmune thyroid disease is a common complication of patients with chronic hepatitis C undergoing combination pegylated interferon-α and ribavirin treatment. A small proportion develops interferon-induced thyroiditis of which the long term natural history is unknown and how it compares with de novo thyroiditis. The aim of the study is to determine the natural history of thyroid disease including antibody profile in this particular setting 36 months from the completion of therapy.

METHODS

A cohort of 18 hepatitis C patients (mean age 45 ± 8 years (standard deviation)) who developed exclusively thyroiditis in this setting was followed every 12 months after the completion of therapy for 36 months. Investigations included thyrotropin, free tetra-iodothyronine, free tri-iodothyronine levels and thyroid autoantibodies.

RESULTS

None of the patients developed any long term thyroid disease. Two patients had a prolonged hypothyroid phase of the thyroiditis early after the completion of treatment but recovered fully. The remaining 16 patients remained euthyroid. Similarly, thyroid autoantibodies all declined and returned to reference range.

CONCLUSIONS

The long term natural history in this small series of interferon induced thyroiditis was benign. If a larger series confirms a similar outcome then there is no long term residual effect on thyroid function and follow-up testing would not be warranted.

Thyroid hormonal disturbances related to treatment of hepatitis C with interferon-alpha and ribavirin

OBJECTIVE

To characterize thyroid disturbances induced by interferon-alpha and ribavirin therapy in patients with chronic hepatitis C.

INTRODUCTION

Interferon-alpha is used to treat chronic hepatitis C infections. This compound commonly induces both autoimmune and non-autoimmune thyroiditis.

METHODS

We prospectively selected 26 patients with chronic hepatitis C infections. Clinical examinations, hormonal evaluations, and color-flow Doppler ultrasonography of the thyroid were performed before and during antiviral therapy.

RESULTS

Of the patients in our study, 54% had no thyroid disorders associated with the interferon-alpha therapy but showed reduced levels of total T3 along with a decrease in serum alanine aminotransferase. Total T4 levels were also reduced at 3 and 12 months, but free T4 and thyroid stimulating hormone (TSH) levels remained stable. A total of 19% of the subjects had autoimmune interferon-induced thyroiditis, which is characterized by an emerge of antithyroid antibodies or overt hypothyroidism. Additionally, 16% had non-autoimmune thyroiditis, which presents as destructive thyroiditis or subclinical hypothyroidism, and 11% remained in a state of euthyroidism despite the prior existence of antithyroidal antibodies. Thyrotoxicosis with destructive thyroiditis was diagnosed within three months of therapy, and ultrasonography of these patients revealed thyroid shrinkage and discordant change in the vascular patterns.

DISCUSSION

Decreases in the total T3 and total T4 levels may be related to improvements in the hepatocellular lesions or inflammatory changes similar to those associated with nonthyroidal illnesses. The immune mechanisms and direct effects of interferon-alpha can be associated with thyroiditis.

CONCLUSION

Interferon-alpha and ribavirin induce autoimmune and non-autoimmune thyroiditis and hormonal changes (such as decreased total T3 and total T4 levels), which occur despite stable free T4 and TSH levels. A thyroid hormonal evaluation, including the analysis of the free T4, TSH, and antithyroid antibody levels, should be mandatory before therapy, and an early re-evaluation within three months of treatment is necessary as an appropriate follow-up.

Cases of interferon-alpha and interferon-beta-induced thyroiditis

Interferons are currently the major treatment modality for several malignant and non-malignant diseases such as chronic hepatitis C and B, multiple sclerosis, hematological malignancies, malignant melanoma, renal cell carcinoma, etc. Thyroid disorders develop in some of the interferon-treated patients with the incidence ranging from 1% to 35%. These complications may often result in dose reduction or discontinuation of interferon therapy. Interferon induced thyroid disorders can be classified as autoimmune and non-autoimmune thyroiditis. There are many studies on the development of thyroid dysfunction in interferon-alpha treated patients with chronic hepatitis C and in patients with multiple sclerosis treated with interferon-beta. There is a dearth of information about the incidence and characteristics of thyroid abnormalities in patients with hematological malignancies receiving interferon-alpha. A number of genetic determinants are discussed as causes for thyroid impairment (sex, age, ethnic group, genes involved in the thyroid immune regulation), as well as non-genetic factors (related to the underlying disease--hepatitis C virus; multiple sclerosis; therapeutic regimens of interferon administration, iodine concentration in the environment, presence of thyroid autoantibodies at the start of treatment, etc.). In this article we summarize the relevant data about the frequency and characteristics of thyroid disorders in patients treated with interferons, the risk factors and the mechanisms for their development and the peculiarities of the course, detection and treatment of these complications. The review of the literature motivates studying the thyroid function of specific groups of patients receiving interferon in order to clarify the influence of the factors drug and disease on the thyroid gland. Early detection and adequate treatment of thyroid dysfunction in these patients is important to avoid complications that may compromise treatment.