Do sleepy rheumatoid arthritis patients have a sleep disorder?

Subjective reports of sleep dysfunction are common in people with rheumatoid arthritis (RA). Our objective was to determine whether excess sleepiness in RA is associated with polysomnographic (PSG) abnormalities.

Twelve RA participants with abnormal sleep scores were identified in clinic and age/gender matched to RA participants with normal Epworth Sleepiness Scale (ESS) scores. A total of 25 participants were recruited. All participants underwent overnight PSG studies with measurement of apnoea-hypopnoea indexes (AHI). Questionnaire instruments, including the ESS, Berlin questionnaire for sleep apnoea risk, visual analogue scale for fatigue, modified Health Assessment Questionnaire (mHAQ) and the Center for Epidemiologic Studies - Depression (CES-D) score, along with RA assessments, were reapplied on the PSG study night.

Seven men and 18 women participated. Ten participants had abnormal ESS scores and 15 had normal ESS scores on the PSG night. PSG data revealed that 68% of patients had abnormal AHI (≥ 5). Abnormal ESS (> 10) had an 80% positive predictive value (PPV) for abnormal AHI; the negative predictive value (NPV) of normal ESS was 40%. By contrast, high-risk categorization for obstructive sleep apnoea (OSA) by the Berlin questionnaire had a PPV of 77.8%, and for low-risk status, an NPV of 37.5%.

In the present study population, there was a high prevalence of abnormal AHI consistent with OSA. An abnormal ESS had high positive predictive value for an abnormal AHI.