Young Women with Rheumatoid Arthritis at Increased Risk of Fractures

Newswise — CHICAGO – Women with rheumatoid arthritis are not only at an increased risk of fractures, but are also at an increased risk of suffering a fracture before they reach the age of 50, according to research presented this week at the American College of Rheumatology Annual Scientific Meeting in Chicago.

Rheumatoid arthritis is a chronic disease that causes pain, stiffness, swelling, and limitation in the motion and function of multiple joints. Though joints are the principal body parts affected by RA, inflammation can develop in other organs as well. An estimated 1.3 million Americans have RA, and the disease typically affects women twice as often as men.

Women and men with RA have been shown to be at an increased risk for fractures. In fact, RA is included in the World Health Organization’s recently released prediction tool for osteoporotic fractures in older individuals. However, little is known about the risk of fractures in people with RA who are under the age of 50. Researchers from the Mayo Clinic in Rochester, Minn., recently addressed this by looking at fracture risk according to a person’s age at the time of his or her RA diagnosis.

To determine whether younger people with RA have an increased risk for fractures, the team — led by Shreyasee Amin, MD CM, MPH; associate professor in the Division of Rheumatology at the Mayo Clinic — reviewed the medical records of 1,155 people (ages 18 and older) who were living in the same community when they were first diagnosed with RA and an equal number of people without the disease from the same community. Those without RA were paired with each person with RA based on their sex and year of birth. Medical records of each pair were reviewed for any new fracture that was not related to cancers or severe trauma – such as from a car accident or a fall from more than a standing height.

Next, Dr. Amin’s team compared fractures occurring in each person following their diagnosis of RA to his or her counterpart until their last follow up appointment with their physician. The researchers examined this information, for women and men separately, and with respect to age at the time of diagnosis (above or below the age of 50). The first fracture occurring before age 50 was examined for each pair in order to determine whether people with RA who are under the age of 50 at the time of diagnosis are at increased risk for fractures early in life or only when they get older.

Out of the 1,155 people with RA, (810 of whom were women; 345 were men) 276 women and 87 men suffered a new fracture – with 205 women and 67 men suffering these fractures at the hip, spine, wrist or shoulder (sites typically seen with osteoporotic fractures). These participants were more likely to have a first new fracture over the time of follow-up when compared with their counterparts who did not have RA – regardless of age at the time of RA diagnosis. The results were more conclusive among women than men. Furthermore, women who were under the age of 50 at the time of their RA diagnosis were found more likely than their counterparts without RA to have their first new fracture before they reached the age of 50.

Overall, the researchers found that men with RA were at an increased risk for future fractures, but this risk appeared to occur when they were older. Women with RA were not only found to be at an increased risk of future fracture, but those who developed the disease when they were young were also at an increased risk of suffering those fractures before the age of 50 – leading the researchers to conclude that fracture prevention is an important part of health care management for young women with RA.

“Young women with RA need to be aware that they are at an increased risk for fracture – even though they are young,” says Dr. Amin. Understanding what contributes to the risk for fractures for all with RA, including young women with RA, would help us better prevent them.”

The American College of Rheumatology is an international professional medical society that represents more than 8,000 rheumatologists and rheumatology health professionals around the world. Its mission is to advance rheumatology. The ACR/ARHP Annual Scientific Meeting is the premier meeting in rheumatology. For more information about the meeting, visit www.rheumatology.org/education. Follow the meeting on Twitter by using the official hashtag: #ACR2011.

Editor’s Notes: Shreyasee Amin, MD, CM, MPH, will present this research during the ACR Annual Scientific Meeting at the McCormick Place Convention Center at 3:15 PM on Monday, November7 in room W471b. Dr Amin will be available for media questions and briefing at 1:30 PM on Tuesday, November 8 in the on-site press conference room, W 175C.

Learn more about living well with rheumatic disease as well as rheumatologists and the role they play in health care. Also, discover the ACR’s Simple Tasks campaign, which highlights how rheumatic diseases strike women disproportionately and in the prime of their lives

Presentation Number: 1632

Fracture Risk Is Increased in Young Women with Rheumatoid Arthritis

Shreyasee Amin (Mayo Clinic, Rochester, MN)Sherine E. Gabriel (Mayo Clinic, Rochester, MN)Sara J. Achenbach (Mayo Clinic, Rochester, MN)Elizabeth J. Atkinson (Mayo Clinic, Rochester, MN)L. Joseph Melton III (Mayo Clinic, Rochester, MN)

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.

Method: 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.

Result: 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

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.

Disclosure: S. Amin, Merck Pharmaceuticals, 5 ; S. E. Gabriel, None; S. J. Achenbach, None; E. J. Atkinson, None; L. J. Melton III, None.

View the full abstract at www.rheumatology.org