Subjective sleep disturbances at the time of diagnosis in patients with polymyalgia rheumatica and in patients with seronegative elderly-onset rheumatoid arthritis. A pilot study

OBJECTIVES: To investigate subjective sleep disturbances in patients with recent-onset polymyalgia rheumatica (PMR) and in patients with recent-onset seronegative elderly-onset rheumatoid arthritis (SEORA). MATERIAL AND METHODS: The study involved patients consecutively referred to two outpatient clinics from January to June 2018, with a diagnosis of PMR according to 2012 European League Against Rheumatism and American College of Rheumatology provisional criteria, and patients with a diagnosis of SEORA according to 1987 American Rheumatism Association criteria + age + absence of rheumatoid factor and anti-citrullinated peptide antibodies. All patients were naive to glucocorticoid (GC) therapy. After informed consent, we asked the patients to fill out a questionnaire including the Medical Outcomes Study – Sleep Scale (MOS-SS), pain Visual Analogic Scale (VAS), Cumulative Illness Rating Scale (CIRS), Neuropsychiatric Inventory (NPI), and how many minutes their morning stiffness (MS) lasted, at baseline and after 1 (T1) and 12 (T2) months. Differences between groups were calculated with the t-test; all p-values were two-sided and p < 0.05 was used to determine statistical significance. The study was approved by the local ethics committee and carried out in accordance with the Helsinki Declaration. RESULTS: The MOS-SS scores and MS duration were the only variables to show at T0 a significant difference between the two groups. In particular, MOS-SS scores were 47.6 ±8.4 (PMR) and 28.26 ±12.4 (SEORA), with p-values = 0.000. The MS duration was 90 ±9.9 minutes and 45 ±5.5 minutes, with p-value = 0.000. At T1 and T2, MOS-SS scores and MS duration decreased in the two groups, and no significant differences were found. CONCLUSIONS: The study suggests that the assessment of subjective sleep disturbances can be useful in the differential diagnosis between recent-onset PMR and SEORA.