Programa de triagem neonatal para hipotireoidismo congênito no nordeste do Brasil: critérios diagnósticos e resultados

Predictive factors for the diagnosis of permanent congenital hypothyroidism and its temporal changes in Sergipe, Brazil - A real-life retrospective study

Objective

Congenital hypothyroidism (CH) can be permanent (PCH) or transient (TCH). While the importance of thyroxine in myelination of the brain is undisputed, the benefits to neurodevelopmental outcomes of TCH treatment are controversial. Our objectives were to determine predictive factors for PCH and verify its prevalence changes over time.

Subjects and methods

A total of 165 children were evaluated at 3 years of age to verify the diagnosis of PCH. 130 were submitted to a two-step cluster analysis, with the aim of grouping them into homogeneous clusters. The mean incidence of PCH and TCH was calculated from 2004 to 2010 and 2011 to 2015.

Results

Sixty-six children were diagnosed with PCH, and 99 were diagnosed with TCH. Eighty-one percent of PCH children and all TCH children with thyroid imaging had glands in situ. Eighty children (61.5%) were in Cluster 1, 8 children (6.2%) were in Cluster 2 and 42 children (32.3%) were in Cluster 3. No children had PCH in Cluster 1, while 87.5% of children in Cluster 2 and all children in Cluster 3 had PCH. The most important predictor for PCH was the initial serum TSH, which was marginally higher in importance than the blood spot TSH, followed by the initial serum free T4. The mean incidence of PCH (odds ratio: 1.95, 95% CI 1.36 to 2.95, p < 0.0001) and TCH (odds ratio 1.33, 95%, CI 1.02 to 1.77, p = 0,038) increased over time.

Conclusion

The most important PCH predictors are the initial serum TSH and the blood spot TSH. The mean incidence of both PCH and TCH in our series increased.

Impact of the reduction in TSH cutoff level to 6 mIU/L in neonatal screening for congenital hypothyroidism in Santa Catarina: final results

OBJECTIVE

To assess the implications of changing the cutoff level of TSH from 10 to 6 mIU/L.

METHODS

The study population was constituted by 74.123 children screened for congenital hypothyroidism by the National Screening Program in Santa Catarina, from March 2011 to February 2012. The cutoff of TSH was 6 mIU/L. If TSH between 6-10 mIU/L, the newborn was recalled for a second TSH measurement on filter paper. If TSH > 6 mIU/L in the second sample, the child was sent for medical evaluation. In children with normal topic thyroid, levothyroxine was suspended for 1 month at the age of 3 years for identification of the etiology and evaluation of the need to continue treatment.

RESULTS

Among the children screened, 435 were recalled for presenting TSH between 6 and 10 mIU/L in the first sample, 28 remained TSH > 6 mIU/L in the second sample. Among these, 11 had a final diagnosis of dyshormonogenesis, two of ectopic thyroid, two of thyroid hypoplasia and one of transient hypothyroidism. Ten children presented normal TSH levels on the first medical evaluation and two lost follow-up.

CONCLUSION

A decrease in the TSH cutoff level from 10 to 6 mIU/L in a neonatal screening program for congenital hypothyroidism reduced the number of false-negative results, increasing the sensitivity of the test, but increased the number of false-positive results and recalls. Since a TSH cutoff level of 6 mIU/L detects thyroid function abnormalities requiring treatment, the adoption of this cutoff level is justified.

Update on Neonatal Isolated Hyperthyrotropinemia: A Systematic Review

The purpose of this paper was to systematically summarize the published literature on neonatal isolated hyperthyrotropinemia (HTT), with a focus on prevalence, L-T4 management, re-evaluation of thyroid function during infancy or childhood, etiology including genetic variation, thyroid imaging tests, and developmental outcome. Electronic and manual searches were conducted for relevant publications, and a total of 46 articles were included in this systematic review. The overall prevalence of neonatal HTT was estimated at 0.06%. The occurrence of abnormal imaging tests was found to be higher in the persistent than in the transient condition. A continuous spectrum of thyroid impairment severity can occur because of genetic factors, environmental factors, or a combination of the two. Excessive or insufficient iodine levels were found in 46% and 16% of infants, respectively. Thirty-five different genetic variants have been found in three genes in 37 patients with neonatal HTT of different ethnic backgrounds extracted from studies with variable design. In general, genetic variants reported in the TSHR gene, the most auspicious candidate gene for HTT, may explain the phenotype of the patients. Many practitioners elect to treat infants with HTT to prevent any possible adverse developmental effects. Most patients with thyroid abnormalities and/or carrying monoallelic or biallelic genetic variants have received L-T4 treatment. For all those neonates on treatment with L-T4, it is essential to ensure follow-up until 2 or 3 years of age and to conduct medically supervised trial-off therapy when warranted. TSH levels were found to be elevated following cessation of therapy in 44% of children. Withdrawal of treatment was judged as unsuccessful, and medication was restarted, in 78% of cases. Finally, data extracted from nine studies showed that none of the 94 included patients proved to have a poor developmental outcome (0/94). Among subjects presenting with normal cognitive performance, 82% of cases have received L-T4 therapy. Until now, the precise neurodevelopmental risks posed by mild disease remain uncertain.

Neonatal screening: 9% of children with filter paper thyroid-stimulating hormone levels between 5 and 10μIU/mL have congenital hypothyroidism

OBJECTIVES

To determine the prevalence of congenital hypothyroidism in children with filter-paper blood-spot TSH (b-TSH) between 5 and 10μIU/mL in the neonatal screening.

METHODS

This was a retrospective study including children screened from 2003 to 2010, with b-TSH levels between 5 and 10μIU/mL, who were followed-up during the first two years of life when there was no serum TSH normalization. The diagnosis of congenital hypothyroidism was defined as serum TSH ≥10μIU/mL and start of levothyroxine treatment up to 2 years of age.

RESULTS

Of the 380,741 live births, 3713 (1.04%) had filter paper TSH levels between 5 and 10μIU/mL and, of these, 339 (9.13%) had congenital hypothyroidism. Of these, 76.11% of the cases were diagnosed in the first three months of life and 7.96% between 1 and 2 years of age.

CONCLUSION

The study showed that 9.13% of the children with b-TSH levels between 5 and 10μIU/mL developed hypothyroidism and that in approximately one-quarter of them, the diagnosis was confirmed only after the third month of life. Based on these findings, the authors suggest the use of a 5μIU/mL cutoff for b-TSH levels and long-term follow-up of infants whose serum TSH has not normalized to rule out congenital hypothyroidism.

The incidence of congenital hypothyroidism (CH) in Guangxi, China and the predictors of permanent and transient CH

BACKGROUND

The incidence of congenital hypothyroidism (CH) differs significantly among different ethnicities and regions, and early differentiation of transient CH is important to avoid unnecessary prolonged treatment with L-T4.

OBJECTIVE

To investigate the incidence of CH based on the newborn screening program in Guangxi Zhuang Autonomous Region, China, and to analyze the predictors that might allow for an early differentiation between permanent (P) and transient (T) CH.

DESIGN AND METHODS

Data from newborn screening program over a seven-year period (January 2009 to January 2016) at Guangxi Maternal and Child Health Hospital are analyzed. Blood samples were collected on filter paper between 3 and 7 days after birth, and TSH level was measured by time-resolved fluorescence assay. Individuals with increased TSH (TSH ≥ 8 IU/L) levels detected by newborn screening were recalled for further evaluation. Serum TSH, FT3 and FT4 were determined by electrochemiluminescence assay using venous blood samples. Diagnosis of CH is based on elevated TSH levels (>10 IU/L) and decreased FT4 levels (<12 pmol/L). Patients with elevated TSH levels and normal FT4 levels were diagnosed as hyperthyrotropinemia. Permanent or transient CH was determined by using the results of thyroid function tests after temporary withdrawal of L-T4 therapy at approximately 2-3 years of age.

RESULTS

Among 1,238,340 infants in the newborn screening program, 14,443 individuals were recalled for reevaluation (re-call rate 1.18%), 911 and 731 individuals were subsequently determined to have hyperthyrotropinemia and CH respectively; thus, a prevalence of 1:1359 and 1:1694 for hyperthyrotropinemia and CH. Of the 731 patients with CH, 161 patients were diagnosed with permanent CH (PCH), and 159 patients were diagnosed with transient CH (TCH), the other 411 patients are too young to determine their subtypes. Patients with PCH required an increasing dose of L-T4 during the first few years, whereas patients with TCH required a decreased dose of L-T4. The TSH levels at diagnosis and the dose of L-T4 used were significantly higher in PCH cases than in transient cases. The FT4 levels at diagnosis were significantly lower in PCH cases than in TCH cases. The TSH levels at diagnosis, FT4 levels at diagnosis and L-T4 doses at 90 days were evaluated as predictors for differentiating PCH and TCH, and their accuracy at their respective optimal cutoffs were determined to be 60.6%, 66.7% and 93.9%, respectively.

CONCLUSIONS

The CH incidence in Guangxi Zhuang Autonomous Region is slightly higher (1:1694) compared to the worldwide levels (1/2000-1/4000). The PCH and TCH ratio is close to 1; thus, the estimated PCH incidence is 1/3388, which is similar to reported worldwide average incidence (1/3000). The L-T4 dose required at 90 days (>30 μg/day) has the highest predictive value for PCH. Earlier differentiation of PCH and TCH helps to determine appropriate treatment course.

Detecting congenital hypothyroidism with newborn screening: the relevance of thyroid-stimulating hormone cutoff values

OBJECTIVES

To assess the prevalence of congenital hypothyroidism and the ability of various neonatal thyroid-stimulating hormone (TSHneo) cutoff values to detect this disease.

METHODS

This cohort study was based on the retrospective collection of information available from the Reference Service for Newborn Screening database for all live births from January 1, 2010, to December 31, 2012, assessed using the Newborn Screening Program of a Brazilian state, Brazil. The infants were divided into two groups: I - Control: infants with normal newborn screening tests and II - Study: infants with congenital hypothyroidism. Analysis included comparing the TSHneo levels from both groups. A receiver operating characteristic (ROC) curve was constructed to assess the TSHneo cutoff values.

RESULTS

Using a TSHneo cutoff value of 5.0μIU/mL, 50 out of 111,705 screened infants had diagnosis of congenital hypothyroidism (prevalence 1:2234 live births). The ROC curve showed that TSHneo value of 5.03μIU/mL had 100% sensitivity and the greatest associated specificity (93.7%). The area under the curve was 0.9898 (p<0.0001).

CONCLUSIONS

The ROC curve confirmed that the TSHneo cutoff value of 5.0μIU/mL adopted by the Newborn Screening Program of a Brazilian state was the most appropriate for detecting congenital hypothyroidism and most likely explains the high prevalence that was found.

Evolution to permanent or transient conditions in children with positive neonatal TSH screening tests in Sergipe, Brazil

OBJECTIVES

To assess the evolution to permanent or transient conditions in children with positive neonatal TSH tests in Sergipe, Brazil, from 2004 to 2010.

SUBJECTS AND METHODS

Out of 193,794 screened newborns, 713 presented a neonatal TSH level higher than the local cutoff (5.2 µU/mL). From the confirmatory serum TSH values, the children were diagnosed with initial congenital hypothyroidism (CH) or suspect CH. From the evolution, they were classified as permanent CH, hyperthyrotropinemia, or transient TSH elevation. The mean incidence of each final condition was calculated for the total period of time.

RESULTS

The initial diagnosis included 37 CH (18.1%) and 167 suspect CH (81.9%) cases. The final diagnosis included 46 cases of permanent CH (22.5%), 56 of hyperthyrotropinemia (27.5%), and 102 of transient TSH elevation (50.0%). Out of the 37 cases of initial CH, 23 (62.2%) had permanent CH, nine (24.3%) had hyperthyrotropinemia, and five (13.5%) had transient TSH elevation. Out of the 167 suspect CH cases, 23 (13.8%) had permanent CH, 47 (28.1%) had hyperthyrotropinemia and 97 (58.1%) had transient TSH elevation. The mean incidence after the follow up was 1:4,166 for permanent CH, 1:3,448 for hyperthyrotropinemia, and 1:1,887 for transient TSH elevation. Eighty-six percent of the children with an initial diagnosis of CH and 41.9% with suspect CH had a permanent condition (CH or hyperthyrotropinemia).

CONCLUSIONS

The follow-up of children with an initial diagnosis of CH or suspect CH is necessary to determine whether the disorder is permanent because predicting the evolution of the condition is difficult.

Evaluation of effectiveness and outcome of PKU screening and management in the State of Sergipe, Brazil

OBJECTIVES

Phenylketonuria (PKU) was the first inherited metabolic disease known to cause mental retardation for which a newborn screening program (NBS) was developed. The objective of this study was to evaluate the effectiveness of PKU NBS and the management of cases in the northeastern Brazilian state of Sergipe (SE).

MATERIALS AND METHODS

We reviewed the phenylalanine concentrations in filter-paper collected from the heel (PKUneo) of 43,449 newborns; blood concentrations obtained by venipuncture in the subjects with abnormal PKUneo; the children's age at several phases of the program, the incidence of the disease from January 2007 to June 2008; and metabolic control of the patients.

RESULTS

The coverage of NBS/SE was 78.93%. The children's age was 10 ± 7 days at PKUneo collection. Twelve children were recalled based on the PKUneo cutoff value at 28 ± 13 days. From these, the concentrations of phenylalanine collected by venipuncture were normal in five children. The incidence of hyperphenylalaninemia was 1/43,449, and of PKU was 1/8,690 (5 cases). One suspected subject died. Another death occurred in the cohort, in a confirmed PKU case. PKU treatment began within 51 ± 12 days of life. In the four patients under dietary phenylalanine restriction, metabolic control was often difficult.

CONCLUSIONS

PKU NBS/SE has satisfactory coverage and adequate cutoff for recalling patients and diagnosis, but the onset of treatment is delayed, and follow-up metabolic control is frequently inadequate.

[Evolution of the neonatal screening program in the state of Tocantins]

OBJECTIVE

To evaluate the Neonatal Screening Program in the State of Tocantins from 1995 to 2011.

MATERIALS AND METHODS

Data collection was conducted by means of interviews with those responsible for the service, by the analysis of medical records of patients diagnosed with phenylketonuria (PKU) and congenital hypothyroidism (CH) that were enrolled in the program, and by interviews with parents and/or guardians of the patients monitored.

RESULTS

Program coverage increased from 32.3% to 76.6% after the implementation of the National Newborn Screening Program (PNTN). The prevalence of PKU and CH was 1:28,309 and 1:4,632 live births, respectively. The mean ages at the collection of the first blood sample (PKU: 9.6 ± 6.3 days; CH: 13.3 ± 10.3 days) and at the beginning of the treatment (PKU: 57.0 ± 17.6 days; CH: 95,6 ± 57.6 days) were greater than recommended by the Ministry of Health. The quality of monitoring was considered satisfactory by 100% of the parents.

CONCLUSION

Although there have been great developments in neonatal screening program in this state, there is need for greater government incentives to optimize the program and to make the PNTN advance to its next phases.

Incidence of congenital hypothyroidism in the city of Uberaba/Minas Gerais and etiological evaluation of the affected subjects

OBJECTIVE

The objective of this study was to determine the incidence and etiology of congenital hypothyroidism (CH) in Uberaba, MG.

SUBJECTS AND METHODS

From 2001 to 2010, by reviewing patient files from a public reference outpatient unit. The screening program covered 88% of live-born children.

RESULTS

CH was diagnosed in 16 children, representing an incidence of 1:2,017 live-born children screened. The etiological evaluation was done in 15 children and revealed seven cases of thyroid dysgenesis, seven of dyshormonogenesis, and one case of transient hypothyroidism. One child moved away from the state before etiological investigation was carried out.

CONCLUSION

We concluded that both the incidence of CH and of dyshormonogenesis as the main causes of CH were increased in the investigated region, but molecular studies are necessary for a better definition of etiology.

Avaliação do valor de corte de TSH em amostras de filtro na triagem neonatal para diagnóstico de hipotireoidismo congênito no Programa "Primeiros Passos" - IEDE/RJ

OBJETIVO: Analisar casos de hipotireoidismo congênito (HC) confirmados ou não, triados pelo Programa "Primeiros Passos", estratificando-os em faixas de TSH em filtro (TSH-F). MATERIAIS E MÉTODOS: Estratificar, em faixas de TSH-F em função do TSH em soro (TSH-S), os casos convocados para teste confirmatório de janeiro/2006 a julho/2009. RESULTADOS: Cerca de 37% dos casos confirmados (475) apresentaram TSH-F > 9,5 mUi/L, mas a maioria dos casos confirmados estava nas faixas de TSH-F mais baixas. Entre os casos não confirmados (4.613), a maior parte se encontrava nas faixas mais baixas. Não houve faixa de TSH-F exclusiva dos casos não confirmados. CONCLUSÃO: O valor de corte do TSH-F utilizado é fundamental no diagnóstico do HC e deve ser baixo, mesmo que sejam realizados mais testes confirmatórios. Mais estudos são necessários para determinar o melhor valor de corte de TSH-F para triagem neonatal.

[Performance analysis of the Rio de Janeiro State Neonatal Screening Program, 2005-2007]

Guidelines emphasize that the appropriate time frame for neonatal screening with the heel stick test is from the 3rd to 7th day of life, in 100% of newborns. Treatment for congenital hypothyroidism and phenylketonuria, when initiated in the first two weeks of life, is capable of preventing the neurological sequelae of these diseases. The Rio de Janeiro State Neonatal Screening Program was accredited for Phase 2 of the National Neonatal Screening Program, with two program models (A and B). A performance analysis was conducted for the Neonatal Screening Program, for the years 2005 to 2007. Coverage increased from 2002 to 2007, reaching 80.4%, with 33.8% of the blood samples drawn in the first 7 days of life. The two models showed similar performance, short of the targets, with 50% of the confirmed cases receiving their diagnosis at more than 48 days of life. The delays accumulated in the various stages of the process can impede the benefits of early detection, the cornerstone of neonatal screening. The deleterious long-term effects transcend the individual sphere, with an impact on the health system and a major social burden.

Triagem neonatal: o desafio de uma cobertura universal e efetiva

Programas de triagem neonatal (PTN) visam detectar portadores de várias doenças congênitas em recém-natos assintomáticos para uma intervenção efetiva. A coleta do teste é a primeira etapa do processo, devendo ser universal e precoce. Foi feita revisão sobre cobertura e momento de coleta em PTN de diversos países. A busca foi realizada em fontes diversas, de 1998 e 2008, com descritores "triagem neonatal" e "cobertura". A falta de desenho de estudo típico impediu o rigor necessário a uma revisão sistemática. Os dados foram agrupados em macrorregiões. O Canadá teve cobertura de 71% em 2006. A Europa teve cobertura de 69% em 2004, com dados de 38 países. Na Ásia e Pacífico, houve dados de dezenove países. No Oriente Médio e Norte da África, houve dados de quatro países. Na América Latina, a cobertura foi de 49% em 2005, com dados de catorze países. No Brasil, a cobertura foi de 80% em 2005. Sobre o momento da coleta, houve doze relatos. A transição epidemiológica contribuiu para o êxito dos PTN. Regiões mais desenvolvidas têm coberturas e momento de coleta mais adequados. No Brasil, a iniciativa do governo ampliou o acesso ao teste, mas coletas tardias indicam a necessidade de ações educativas e de organizações profissionais na definição de diretrizes específicas.

Avaliação do Serviço de Referência em Triagem Neonatal para hipotireoidismo congênito e fenilcetonúria no Estado de Mato Grosso, Brasil

OBJETIVO: Avaliar o Serviço de Referência em Triagem Neonatal para hipotireoidismo congênito e fenilcetonúria no Estado de Mato Grosso. MÉTODOS: Estudo transversal, utilizando-se dados secundários dos exames realizados no período de janeiro de 2003 a dezembro de 2004. RESULTADOS: Foram feitos 66.337 testes de triagem com uma cobertura populacional inferior a 70%. A prevalência de fenilcetonúria foi de 1:33.068 nascidos vivos, e de hipotireoidismo congênito foi de 1:9.448 nascidos vivos. Apenas 22% das amostras foram coletadas na idade recomendada; a maioria realizou o teste de triagem entre 8 e 30 dias de vida. A mediana da idade na coleta do teste foi de 12 dias. Verificou-se que o serviço teve dificuldades na reconvocação dos casos suspeitos e dificuldades financeiras na obtenção dos insumos laboratoriais. CONCLUSÕES: A idade na coleta e o atraso na fase de confirmação diagnóstica foram os principais motivos para o atraso do início do tratamento dos casos detectados pelo serviço.