Background/Purpose:

 Patients with rheumatoid arthritis (RA) often report fatigue, but a possible impact of disease on sleep and/or on disease activity are poorly characterized. We examined possible relationships between sleep and disease activity.

Methods:

All patients with any diagnosis complete an MDHAQ at each visit to a single rheumatology practice. The MDHAQ includes sections regarding function, pain, patient global estimate, a patient self-reported joint count, fatigue, exercise, AM stiffness and a brief psychological profile.  The MDHAQ includes 3 ”psychological profile” queries  including “Over the past week, were you able to get a good night’s sleep?” (“sleep”). The responses are 0-3 (without difficulty=0, with some difficulty=1, with much difficulty=2, unable to do=3). Each patient with RA also is assessed with an ESR and CRP,  28 tender and swollen joint counts, and a physician global estimate (0-10). From these values, multiple composite indices are calculated, including the DAS28(ESR), CDAI, SDAI and RAPID3. Patients are then characterized into disease activity categories (“remission”, “low disease activity”, “moderate disease activity”, “high disease activity”), according to  established criteria. Using a random visit for each patient, linear regression models were determined using the composite score value as the dependent variable, and “sleep” as the independent variable, to determine possible interactions between “sleep”score and  disease activity scores.  All statistical analyses were performed using Stata v12.

Results:

200 patients with RA had completed responses to “sleep”. The median value for “sleep”=1 (with some difficulty).  A patient with sleep=0 has a 95% chance of being in low CDAI, whereas a patient with sleep=1 has a 95% chance of not being in low CDAI.  A “linear” worsening of CDAI was seen with each increment of “sleep” (fig.1). Similar findings were also seen in comparisons of sleep scores with DAS28, SDAI and RAPID3. (data not shown)  Even if the patient global score is excluded  from this calculation(“mdai”), a similar “linear” result is seen.

Conclusion:

The response to a single question regarding having a good night sleep, explains variation in disease activity according to CDAI in patients with RA. Patients who report significant sleep disturbances are unlikely to be in a low disease state, whereas patients with no sleep disturbances are highly likely to be in a low disease state.