Objective: To study the spectrum of diagnoses, course, and outcome of recent onset arthritis after the age of 60, presenting as rheumatoid arthritis (RA)-like disease.
Methods: A 5 year longitudinal observational study enrolled 92 consecutive patients (median age 73 yrs, 54/38 women/men, median duration of arthritis 12 weeks at inclusion).
Results: Forty-eight percent were classified as having RA according to the 1987 American Rheumatism Association criteria, 52% as non-RA (41.4% undifferentiated seronegative polyarthritis, 10.8% oligoarthritis with polymyalgic symptoms). Symmetrical involvement of small and medium size joints was more predominant in the RA (91 and 84%, respectively) than the non-RA patients (58 and 52%). The patients with RA compared to non-RA had more active and serious disease at onset, reflected by significant differences in number of swollen joints (median values 18 and 9, respectively), duration of morning stiffness (75 and 10 min), physician's global assessment of disease activity (45 and 28 mm on visual analog scale), and Health Assessment Questionnaire (HAQ) score for functional disability (1.8 and 1.0). Improvement during the course was observed in disease process variables as well as in HAQ disability score for both RA and non-RA patients. Risk factors for a poor 5 year functional outcome were female sex (OR 4.24), diagnosis of RA (OR 3.28), and baseline HAQ score > or =1.4 (OR 3.52). The median change in radiological progression (Larsen-Dale index) was zero. Twenty patients died during followup, the majority from cardiovascular diseases, infections, and malignancies. Mortality compared to the age and sex matched general population was increased for rheumatoid factor (RF) positive patients (standardized mortality ratio 272). Mortality risk factors within the patient cohort were male sex (OR 4.35), age (OR 1.17), and having RF+ RA (OR 11.93).
Conclusion: Arthritis in the elderly is a heterogeneous group of arthritides with an overall favorable functional prognosis. The subgroup of women with elderly onset RA with functional disability at onset is at risk for a less favorable functional outcome. Mortality was increased for the patients with RF+ elderly onset RA only.