Hip involvement in seropositive rheumatoid arthritis. Survivorship analysis with a 15-year follow-up

In a prospective survey of recent arthritis 96 patients had erosive and seropositive rheumatoid arthritis (RA). Severe radiological changes in the hipjoint (Larsen grade 3-5) were observed in 31 (32%) and acetabular protrusion in five (5%) patients 15 years after the onset of arthritis. At the end of follow-up Larsen score 0-100 of peripheral joints (p < 0.015), HAQ (p < 0.001), ESR (p < 0.001), and CRP (p < 0.01) were significantly higher in patients with hip joint destruction than in those without. Secondary amyloidosis was found in eight patients with and in three patients without hip involvement (p = 0.002). In survivorship analysis (the Larsen 0-2 grade hips) an overall predicted rate of survival was 80% after 14 years of rheumatoid arthritis. When analyzed according to HLA-B27 the rate of radiological survival for the patients with a positive test was 62% and 87% for the others (p = 0.02). In conclusion, RA patients with high number of destructive peripheral joints (Larsen score) and high ESR or CRP should be carefully monitored due to the increased risk of hip destruction.