Association between sleep apnea and tuberculosis – A nationwide population-based study

Rationale Patients with sleep apnea (SA) have various co-morbidities, particularly metabolic disorders, cardiovascular and cerebrovascular diseases. A recent study showed SA was associated with higher mortality in septic patients, suggesting its possible effect on immune response. However, no study to date had discussed theassociation between SA and tuberculosis (TB). We therefore conducted a nationwide population-based study using Taiwan National Health Insurance (NHI) database. Methods The dataset used for this study is a cohort of 1 million subjects randomly sampled from individuals enrolled in the Taiwan NHI system in 2005. We enrolled adult patients with a diagnosis of SA in the dataset. Patients with a diagnosis of TB prior to SA were excluded. The date of the first SA diagnosis was defined as the index date for each patient. Each SA patient was matched to 30 randomly-selected, age- and sex-matched control subjects without any diagnosis of SA. The control subjects were assigned index dates as their corresponding SA patients without diagnosis of TB before. The incidences of TB in both groups were compared. Results A total of 6135 SA patients and 184050 control subjects were identified. Significantly lower TB incidence was noted in SA patients than control subjects (0.33% v.s. 0.56%, p=0.0167). The cumulative incidence of TB was also lower in SA patients (p =0.0165). After adjusting for age, sex and comorbidities, SA remained a significant protective factor for TB (hazard ratio = 0.509 [95% confidence incidence: 0.327 – 0.793], p = 0.0028). Conclusions Our study revealed significantly lower TB incidence in SA patients than in control subjects. The underlying mechanisms deserve further study.