Rheumatoid Arthritis Increases Risk of Obstructive Sleep Apnoea

The risk of developing obstructive sleep apnoea (OSA) is higher among individuals with rheumatoid arthritis (RA) than those without the disease, according to a study published in BMJ.

For the retrospective cohort analysis, investigators used reimbursement claims data from the Longitudinal Health Insurance database for Catastrophic Illness Patients (LHID-CIP)—–which is part of the National Health Insurance Research Database (NHIRD) of Taiwan––to compare the risk of OSA between patients with RA and those without.

For the RA cohort, investigators used the LHID-CIP file to identify 33,418 patients who were newly diagnosed with RA between 2000 and 2010. The non-RA comparison cohort included 33,418 individuals free of RA and OSA, who were frequency matched by age, sex, and diagnosis year.

Both cohorts were followed up until an OSA diagnosis, withdrawal from the insurance program, death, or until the end of 2011. The Cox proportion hazards regression analysis was used to calculate the HRs of OSA.

The results of study showed the overall incidence rate of OSA was 75% higher in the RA cohort compared with the non-RA cohort (3.04 versus 1.73/10,000 persons-years, respectively) with an adjusted HR of 1.75 (95% CI 1.18 to 2.60).

The incidence rates of OSA were higher in males than females, and in patients with any selected comorbidity, than in those without the comorbidity. In the multivariable model analyses, the risk of OSA was 4.19-fold higher in males compared with females, and was higher in patients with hyperlipidemia, IHD, and obesity.

Stratified analyses by sex, age group, and comorbidity showed that the incidence rates of OSA associated with RA were higher in all subgroups.

Limitations to the study were that investigators used the ICD-9-CM algorithm to define RA, OSA, and comorbidities; NHIRD did not provide detailed information on RA or OSA severity, nor the potential factors, such as body weight, height history of RA and/or OSA, and lifestyles, including drinking and smoking habits; relevant clinical variables, such as PSG results, image reports, and serum laboratory data, were unavailable in the study; estimates of elevated risk of OSA were most likely conservative due to the requirement for PSG to define OSA; and because of the higher overall prevalence of OSA in men, it is likely that OSA is disproportionately under-recognized in women.

The results of the study suggest that patients with RA are at an increased risk of developing OSA, and it is important to evaluate sleep quality and quantity for patients with RA to detect OSA occurrence and reduce further complications, the authors concluded.