La apnea obstructiva del sueño debe evaluarse en la altitud en que viven los pacientes / The importance of evaluating obstructive sleep apnea patients at their home altitude

Antecedentes: Debido a la disponibilidad de los laboratorios de sueño, muchos residentes de comunidades montañosas deben descender de la altura para ser evaluados. Esto puede generar resultados erróneos con respecto a la gravedad y a la naturaleza de la apnea de sueño. Diseño: Once pacientes no diagnosticados previamente de apnea de sueño que viven a 2 400 msnm en Colorado, tuvieron estudios de sueño diagnósticos en la altitud de su hogar, a 1370 m y 5 de los 11 también fueron estudiados a nivel del mar. Resultados: El índice medio de apnea (IMA descendió de 49.1 (10.5)/h a 37.0 (11.2)/h al bajar desde más de 2400 m a 1370 m (p = 0.022). En los 5 sujetos que viajaron hasta el nivel del mar descendió de 53.8 (13.2)/h que tenían en la altitud de su hogar a 47.1 (14.8)/h a 1 370 m, y a 33.1 (12.6)/h a nivel del mar (p = 0.018). La reducción en el IMA fue debida principalmente a una disminución de las hipopneas y apneas centrales, con pocos cambios en la frecuencia de las apneas obstructivas. La duración de estas últimas se prolongó con el descenso. De 8 pacientes con IMA < 50/h en la altitud de su vivienda, dos tuvieron una caída de su IMA a < 5/h a 1 370 m, y un tercero descendió a < 5/h a nivel del mar, es decir por debajo del umbral considerado por muchos médicos para suministrar tratamiento. Los pacientes con la apnea obstructiva del sueño más grave presentaron la menor mejoría con el descenso. Conclusiones: Debido a que el IMA se reduce significativamente con el descenso desde la altura, la polisomnografía es más precisa cuando se realiza al nivel de la altitud del domicilio del paciente. El descenso a laboratorios de sueño puede determinar falsos negativos en pacientes con apnea de sueño leve o moderada.

Epidemiology of adult obstructive sleep apnoea syndrome in India.

There is a paucity of published Indian studies on the prevalence and risk factors of obstructive sleep apnoea (OSA) in adults. The limited published literature, however, does not suggest significant differences in the prevalence and risk factors for OSA and obstructive sleep apnoea syndrome (OSAS) as compared to western studies. Well designed studies are required from all parts of India. Patients should be screened carefully before referring them to costly investigations such as overnight polysomnography. With the background of increasing urbanization, fast growing economy and changes in lifestyle, India will have an epidemic of obesity. Therefore, future studies on the association of OSA and metabolic syndrome should carefully evaluate confounding effect of obesity on metabolic abnormalities in patients with OSA.

Ethnicity as a risk factor for obstructive sleep apnea: comparison of Japanese descendants and white males in São Paulo, Brazil

Some studies showed that Asians with obstructive sleep apnea (OSA) are thinner than Caucasians. Because obesity is a major risk factor for OSA, it was concluded that Asians are predisposed to OSA. However, body fat composition varies for a same body mass index (BMI) according to ethnicity. We firstly compared anthropometric characteristics, symptoms and associated disorders in all consecutive male Japanese descendants and white males with OSA referred for polysomnography. In a second analysis, all Japanese descendants were compared to a subgroup of white males, matched for apnea/hypopnea index and age. In the first analysis, age, symptoms, OSA severity and co-morbidities were similar among Japanese descendants (N = 54) and white patients (N = 466). However, Japanese descendants had a lower BMI than white patients: 27.1 (25.5-28.4) vs 29.4 (26.5-33.0) kg/m², respectively (P < 0.001). In the second analysis, Japanese descendants had a lower BMI than white patients (P < 0.001). Multiple linear regression considering the entire group revealed that age, BMI, neck circumference, Epworth sleepiness scale, ethnicity and percentREM sleep were independent predictors for apnea/hypopnea index (P < 0.001). Ethnicity was no longer significantly associated with OSA severity when we adopted the World Health Organization criteria for obesity (≥25 and 30 kg/m² among Japanese descendants and white males, respectively). Japanese descendants with OSA have a lower BMI than white subjects of similar severity. However, ethnicity was not associated with OSA severity when an ethnical difference in obesity criteria was respected. Our data suggest that Japanese descendants are not predisposed to OSA.