The Influence of BMI in Asthma: Which Traits Are due to Obesity and Which to the Asthma and Obesity Phenotype?

Background: The characteristics of the asthma and obesity phenotype have been described in cluster studies but have not been subsequently confirmed. Specific characteristics of this phenotype have not been differentiated from those inherent to the patient’s body mass index (BMI). Objectives: This study aims to assess the effect of BMI on asthma in order to identify which traits could define the asthma and obesity phenotype and which are inherent to the patient's BMI. Methods: A real-life retrospective observational study was conducted based on data from 2514 patients with suspected asthma collected at the first visit to the allergy clinic between November 2014 and November 2017. All patients had to perform an appropriate spirometry maneuver. All BMI, sex, and age groups were represented. Results: The influence of BMI on asthma differed according to age group and sex. All spirometry results and FeNO were influenced by BMI. The only notable asthma characteristics were later onset of asthma with higher BMI values. No other differences were found between the BMI groups. Conclusions: The effect of BMI on asthma is age-dependent; therefore, it should be corrected for age. The most important variations are in FeNO and spirometry results. The specific characteristics of the asthma and obesity phenotype are a greater perception of symptoms with fewer alterations in respiratory function tests and a lower prevalence of atopy, rhinitis, and allergy, including allergic asthma. Other characteristics of this phenotype, such as a higher female prevalence or late-onset or noneosinophilic asthma, are nonspecific for this phenotype

Antecedentes : las características del fenotipo del asma y la obesidad se han descrito en estudios grupales, pero no se han confirmado posteriormente. Las características específicas de este fenotipo no se han diferenciado de las inherentes al índice de masa corporal (IMC) del paciente. Objetivos : Este estudio tiene como objetivo evaluar el efecto del IMC sobre el asma para identificar qué rasgos podrían definir el fenotipo del asma y la obesidad y cuáles son inherentes al IMC del paciente. Métodos : Se realizó un estudio observacional retrospectivo de la vida real basado en datos de 2514 pacientes con sospecha de asma recopilados en la primera visita a la clínica de alergia entre noviembre de 2014 y noviembre de 2017. Todos los pacientes tuvieron que realizar una maniobra de espirometría adecuada. Estuvieron representados todos los grupos de IMC, sexo y edad. Resultados : La influencia del IMC sobre el asma difirió según grupo de edad y sexo. Todos los resultados de la espirometría y el FeNO estuvieron influenciados por el IMC. Las únicas características notables del asma fueron la aparición tardía del asma con valores de IMC más altos. No se encontraron otras diferencias entre los grupos de IMC. Conclusiones : El efecto del IMC sobre el asma depende de la edad; por lo tanto, debe corregirse según la edad. Las variaciones más importantes se encuentran en los resultados de FeNO y espirometría. Las características específicas del fenotipo de asma y obesidad son una mayor percepción de los síntomas con menos alteraciones en las pruebas de función respiratoria y una menor prevalencia de atopia, rinitis y alergia, incluido el asma alérgica. Otras características de este fenotipo, como una mayor prevalencia femenina o asma de aparición tardía o no eosinofílica, no son específicas de este fenotipo (AU)

The influence of BMI in asthma. Which traits are due to obesity and which to asthma and obesity phenotype?

BACKGROUND AND OBJECTIVES: Characteristics of the asthma and obesity phenotype have been described by cluster studies, but they have not been subsequently confirmed. Specific characteristics of this phenotype have not been differentiated from those inherent to the patient's body mass index (BMI). This study aims to assess the effect of BMI on asthma. This will allow to identify which traits could define the asthma and obesity phenotype, and which are inherent to the patient´s BMI. METHODS: A real-life retrospective observational study was conducted with a 2,514 patients database. Data was collected on the first visit to the Allergy clinic of all patients who underwent a correct spirometry maneuver due to suspected asthma between November 2014 and November 2017. All BMI, sex and age groups were represented. RESULTS: BMI influence over asthma differed in different age groups and genders. All spirometric results and FeNO were influenced by BMI. Concerning asthma characteristics only a later asthma onset with higher BMI values was observed. No other differences were found between different BMI groups. CONCLUSIONS: The effect of BMI on asthma is age dependent, so it should be corrected for age. The most important variations are on FeNO and spirometric results. The specific characteristics of the asthma and obesity phenotype are a greater perception of symptoms with fewer alterations in respiratory function tests and a lower prevalence of atopy, rhinitis and allergy, including allergic asthma. Other characteristics of this phenotype, such as a higher women prevalence or being late-onset or non-eosinophilic asthma, are non-specific for this phenotype.