Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


Fracture Risk Is Increased in Young Women with Rheumatoid Arthritis.

Amin,  Shreyasee, Gabriel,  Sherine E., Achenbach,  Sara J., Atkinson,  Elizabeth J., Melton III,  L. Joseph

Background/Purpose:

Rheumatoid arthritis [RA] is the only cause of secondary osteoporosis singled out in the WHO's fracture [fx] prediction algorithm, FRAX®. Nevertheless, the risk for fx among younger women and men with RA is not well established. We examined the risk for fx by sex and by age at diagnosis in a population-based RA cohort.

Methods:

We studied a population-based inception cohort of women and men with RA (age >=18 yrs) who fulfilled 1987 ACR criteria for RA between 1955–2007 and an equal number of age- and sex-matched controls from the same underlying population, who were followed until death, migration or the present. All incident fxs were identified through a complete review (inpatient and outpatient) of medical records. Excluding fxs resulting from severe trauma, the risk for first osteoporotic fx [OP fx] (hip, spine, wrist and proximal humerus), and for any first fx following their RA diagnosis was compared with their matched control, stratified by sex, using a Cox proportional hazards model, where follow-up time (until death or last follow-up) ended at the first date reached by either within a pair. We then stratified by age at RA diagnosis (<50 yrs, >=50 yrs). For those <50 yrs with RA, we examined their risk for fx over all available follow-up as well as until age 50 yrs.

Results:

In 1155 RA cases, (810 women and 345 men, mean age at RA diagnosis ± SD: 56 ± 16 yrs and 58 ± 14 yrs, respectively), followed for 12,585 person-yrs [p-y], 205 women, (25%, 23 per 1000 p-y), and 67 men, (19%, 19 per 1000 p-y), had an OP fx, while 276 women, (34%, 31 per 1000 p-y), and 87 men, (25%, 24 per 1000 p-y), had any fx. Women and men with RA were at increased risk for fx relative to controls, regardless of age stratification at diagnosis, although did not reach statistical significance in men when stratified by age (see table). When follow-up was limited to age 50 yrs in the 304 women <50 yrs with RA (mean age at RA diagnosis: 39 yrs), the hazard ratio [HR] for OP fx was 6.7 (95% CI:1.5, 29.5), with 13 women having at least one OP fx (7 per 1000 p-y) vs. 2 (1 per 1000 p-y) in matched controls; the HR for any fx was 1.9 (95% CI: 1.04, 3.4), with 31 women with RA having at least one fx (16 per 1000 p-y) vs. 17 (9 per 1000 p-y) in matched controls. In men <50 yrs with RA (N=109, mean age: 41 yrs), too few had a fx before age 50 yrs (N=2 with OP fx; N=5 for any fx) for robust conclusions on fx risk relative to controls.

 Hazard Ratio (95% CI) by Age at RA Diagnosis
WomenAll<50 yrs>=50 yrs
OP Fx*1.7 (1.4, 2.2)4.3 (2.4, 7.8)1.4 (1.1, 1.8)
Any Fx*1.6 (1.3, 1.9)2.4 (1.6, 3.5)1.4 (1.1, 1.7)
Men   
OP Fx*1.6 (1.1, 2.4)1.4 (0.7, 3.0)1.8 (1.1, 2.8)
Any Fx*1.4 (1.02, 1.9)1.7 (0.9, 3.2)1.4 (0.9, 2.0)
*excludes any severe trauma fx

Conclusion:

Men <50 yrs with RA appear to be at increased risk for future fx, but few fxs occurred before age 50 yrs. Women <50 yrs with RA are not only at high risk for future fx, but their fx risk is increased even before they reach age 50 yrs. Fx prevention strategies for young women with RA are thus important to consider.

To cite this abstract, please use the following information:
Amin, Shreyasee, Gabriel, Sherine E., Achenbach, Sara J., Atkinson, Elizabeth J., Melton III, L. Joseph; Fracture Risk Is Increased in Young Women with Rheumatoid Arthritis. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :1632
DOI:

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