Dados do Trabalho

Título

Sleepiness-insomnia phenotype and obstructive sleep apnea severity–is there an association?

Introdução

The complaint of sleepiness in insomnia patients represents an apparent clinical paradox. Amidst the symptoms that aggregate with insomnia, sleepiness is especially defying since conditions as diverse as depression, circadian rhythm sleep-wake disorders, and narcolepsy cause sleepiness and insomnia. Both sleepiness and insomnia have been associated with obstructive sleep apnea since its first reports. Comorbid obstructive sleep apnea (OSA) is usually suspected in such cases.

Objetivo

We investigated clinical and polysomnographic data regarding the sleepiness-insomnia phenotype of patients from a sleep clinic.

Métodos

A database of consecutive patients referred to a university-affiliated sleep laboratory was analyzed. Besides polysomnography to assess sleep architecture, OSA, and periodic limb movement disorder (PLMD), usual insomnia criteria and validated instruments, including the Epworth sleepiness scale (ESS) and the Symptom Check List-90-R were employed.

Resultados

Among 3808 adults included, 1437 had insomnia criteria (38%) and 2131 (56%) had an ESS score>10. Among the 2371 non-insomnia cases, 1383 (58%) had an ESS score>10. Among the 1437 individuals classified as insomnia cases, 748 (52%; P<0.001) had an ESS score>10, i.e., sleepiness-insomnia phenotype. This group had depression and anxiety scores that were significantly higher than in all other patients. Sleepiness-insomnia phenotype, categorized in three levels of ESS-based sleepiness (mild, moderate, severe), adjusted in multinomial model for confounders as sex, age, use of psychotropic drugs, OSA or PLMD severity, showed the following significant associations: 1) insomnia plus mild sleepiness and insomnia plus moderate sleepiness phenotypes were associated with both anxiety and depression upper-quartile scores; 2) insomnia plus severe sleepiness phenotype was associated with upper-quartile scores of depression and anxiety, and with obesity.

Conclusões

Among insomnia patients, ESS>10 is only slightly less frequent than among sleep laboratory patients and unrelated to OSA. The sleepiness-insomnia phenotype was associated with depression, anxiety, and obesity, three conditions in which inflammation may be involved. Further research targeting inflammatory mechanisms involved in the sleepiness-insomnia relationship is warranted.

Palavras-chave

sleepiness, insomnia, obstructive sleep apnea