Background/Purpose: Elderly-onset RA, EORA, which is defined as rheumatoid arthritis (RA) starting at >60 years of age, has received less attention than young-onset RA. Polymyalgia rheumatica (PMR) is also a common rheumatic disease in the elderly. Eicosanoids are biological lipids that serve a specific role as either activators or suppressors of systemic inflammation and have been involved in the development and progression of arthritis. We hypothesized that eicosanoid-related perturbations are related to arthritic symptoms in the elderly, and by defining the eicosanoid profile we might be able to define elements of inflammation pathobiology in this population.

Methods: ARTIEL (Arthritis in the Elderly) is a recent collection cohort with newly diagnosed arthritis in patients older than 60 years, with blood samples collected at baseline (pre-treatment), 1, 3 and 12 months after treatment, along with physician and patient outcome measures through 12 months. They are compared with randomly control individuals of the same age and gender. A thorough clinical examination was conducted. Patients completed a health assessment questionnaire (HAQ). Disease activity score (DAS)28CRP was calculated. Serum eicosanoids were determined by mass spectrometry at baseline and after 3 months of treatment and were classified in groups according to their eicosanoid precursor: eicosapentaenoic acid (EPA), docosohexanoic acid (DHA) or arachidonic acid (AA). Data processing and statistical analysis were performed in R.

Results: 64 patients (average: 75.15, standard deviation (SD) 6.80) and 18 controls (average: 75.39, SD, 6.04) were analyzed. Of these, 44 were diagnosed with RA and 20 with PMR. At the start of the study, patients had a mean DAS28CRP of 5.72 (SD, 1.05), mean HAQ was 1.64 (SD, 0.73). In addition, 84% of the patients reported scapular pain, and 56% of the patients reported pelvic pain at baseline. After three months of treatment, patients had a DAS28CRP of 2.38 (SD, 1.23), and a HAQ of 0.36 (SD, 0.41). As shown in table 1, several eicosanoids, especially anti-inflammatory species derived from EPA and DHA were significantly downregulated in patients at the start of the study as compared to normal controls. Moreover, similar anti-inflammatory species were even further downregulated in patients with DAS >5.1 compared to patients with DAS<5.1. Three months after treatment, the levels of anti-inflammatory species derived from EPA and DHA went back to normal in responders (DAS28CRP<3.2). However, new proinflammatory species from AA were significantly elevated in non-responder patients (table 1).

Conclusion: These results suggest that certain eicosanoids may be key effectors in arthritis in the elderly and that the disbalance between pro and anti-inflammatory eicosanoids before and after treatment might be related to clinical and therapeutic outcomes in this population.