Objectives To assess the impact of abatacept on sleep quality in patients with rheumatoid arthritis (RA), and the validity of the sleep disturbance scale of the Medical Outcomes Study Sleep Questionnaire (MOS-Sleep).

Methods Data from two randomised, double-blind, placebo-controlled abatacept trials (Abatacept Trial in Treatment of Antitumor necrosis factor IN adequate responders (ATTAIN) and Abatacept in Inadequate responders to Methotrexate (AIM)) were analysed. Sleep quality was assessed using the MOS-Sleep. Changes in the Sleep Disturbance Scale were assessed according to clinical responses (including American College of Rheumatology (ACR) and Disease Activity Score 28 C-reactive protein criteria). Correlations between sleep disturbance and patient-reported outcomes were assessed. The sensitivity to change of sleep disturbance was assessed by calculating the standardised response means (SRMs).

Results 258 abatacept- and 133 placebo-treated patients in ATTAIN and 433 abatacept- and 219 placebo-treated patients in AIM were analysed. In ATTAIN, mean improvements to month 6 were significantly greater for patients treated with abatacept than for placebo patients in sleep disturbance (11.3 vs 2.9, p<0.001), sleep adequacy (9.0 vs 0.6, p<0.05), somnolence (10.5 vs 1.6, p<0.001) and Sleep Problems Index (SPI) I (9.5 vs 1.4, p<0.0001) and II (9.8 vs 2.1, p<0.001); mean improvements in AIM to year 1 were statistically significant for sleep disturbance (12.9 vs 8.9, p<0.05) and SPI I (9.4 vs 6.7, p<0.05) and II (10.4 vs 7.3, p<0.05). Associations between mean improvements in sleep disturbance and clinical responses were statistically significant (3.8, 12.7, 18.0, p<0.001 and 5.0, 11.5, 15.7, p<0.001 for European League Against Rheumatism responses, none, moderate and good in ATTAIN and AIM, respectively; 10.2, 14.4, 22.8, p=0.007 and 10.9, 14.9, 17.7, p=0.006 for ACR 20, 50 and 70 responses in ATTAIN and AIM, respectively). SRMs for sleep disturbance were 0.38 (ATTAIN) and 0.19 (AIM).

Conclusions Abatacept treatment provides significant improvements in multiple aspects of sleep in patients with RA. The Sleep Disturbance Scale of the MOS-Sleep shows validity, reliability and sensitivity to change.