Association between phenotypic and genotypic characteristics and disease severity in individuals with cystic fibrosis / Associação entre as características fenotípicas, genotípicas e a gravidade da doença em indivíduos com fibrose cística

Abstract Objective: To analyze the association between phenotypic and genotypic characteristics and disease severity in individuals with cystic fibrosis treated at a reference center in Minas Gerais, Brazil. Methods: This is a retrospective study that collected clinical and laboratory data, respiratory and gastrointestinal manifestations, type of treatment, Shwachman-Kulczycki score, and mutations from the patients' medical records. Results: The sample included 50 participants aged one to 33 years, 50% of whom were female. Out of the one hundred alleles of the Cystic Fibrosis Transmembrane Conductance Regulator gene, the most prevalent mutations were DeltaF508 (45%) and S4X (18%). Mutation groups were only associated with pancreatic insufficiency (p=0.013) and not with disease severity (p=0.073). The latter presented an association with colonization by Pseudomonas aeruginosa and Staphylococcus aureus (p=0.007) and with underweight (p=0.036). Death was associated with age at diagnosis (p=0.016), respiratory symptomatology (p=0.013), colonization (p=0.024), underweight (p=0.017), and hospitalization (p=0.003). Conclusions: We could identify the association of mutations with pancreatic insufficiency; the association of Staphylococcus aureus colonization and underweight with disease severity; and the lack of association between mutations and disease severity. Environmental factors should be investigated more thoroughly since they seem to have an important effect on disease severity.

RESUMO Objetivo: Analisar a associação entre as características fenotípicas, genotípicas e a gravidade da doença em indivíduos com fibrose cística atendidos em um centro de referência de Minas Gerais, Brasil. Métodos: Trata-se de um estudo retrospectivo, em que os dados clínicos, laboratoriais, as manifestações respiratórias e gastrointestinais, o tipo de tratamento, o escore de Shwachman-Kulczycki e as mutações foram coletados dos prontuários de registros dos pacientes. Resultados: A amostra incluiu 50 participantes, de um a 33 anos de idade, sendo 50% do sexo feminino. Do total de cem alelos do gene Cystic Fibrosis Transmembrane Conductance Regulator, as mutações mais prevalentes foram Delta F508 (45%) e S4X (18%). Os grupos de mutações apresentaram associação somente (p=0,013) com a insuficiência pancreática e não com a gravidade da doença (p=0,073). Esta última apresentou associação com a colonização por Pseudomonas aeruginosa e Staphylococcus aureus (p=0,007) e com baixo peso (p=0,036). O óbito foi associado com a idade no diagnóstico (p=0,016), a sintomatologia respiratória (p=0,013), a colonização (p=0,024), o baixo peso (p=0,017) e a ocorrência de internação (p=0,003). Conclusões: Foi possível observar associação entre as mutações e a presença de insuficiência pancreática; entre a colonização por Staphylococcus aureus e o baixo peso com a gravidade da doença; e ausência de associação entre as mutações e a gravidade da doença. Os fatores ambientais merecem ser investigados mais detalhadamente, pois parecem apresentar impacto importante na gravidade da doença.

Association between phenotypic and genotypic characteristics and disease severity in individuals with cystic fibrosis.

OBJECTIVE: To analyze the association between phenotypic and genotypic characteristics and disease severity in individuals with cystic fibrosis treated at a reference center in Minas Gerais, Brazil. METHODS: This is a retrospective study that collected clinical and laboratory data, respiratory and gastrointestinal manifestations, type of treatment, Shwachman-Kulczycki score, and mutations from the patients' medical records. RESULTS: The sample included 50 participants aged one to 33 years, 50% of whom were female. Out of the one hundred alleles of the Cystic Fibrosis Transmembrane Conductance Regulator gene, the most prevalent mutations were DeltaF508 (45%) and S4X (18%). Mutation groups were only associated with pancreatic insufficiency (p=0.013) and not with disease severity (p=0.073). The latter presented an association with colonization by Pseudomonas aeruginosa and Staphylococcus aureus (p=0.007) and with underweight (p=0.036). Death was associated with age at diagnosis (p=0.016), respiratory symptomatology (p=0.013), colonization (p=0.024), underweight (p=0.017), and hospitalization (p=0.003). CONCLUSIONS: We could identify the association of mutations with pancreatic insufficiency; the association of Staphylococcus aureus colonization and underweight with disease severity; and the lack of association between mutations and disease severity. Environmental factors should be investigated more thoroughly since they seem to have an important effect on disease severity.