Incidence Rate and Factors Associated With Fractures Among Medicare Beneficiaries With Ankylosing Spondylitis in the United States

OBJECTIVE

We evaluated the incidence rate and factors associated with fractures among adults with ankylosing spondylitis (AS).

METHODS

We performed a retrospective cohort study with data from the Rheumatology Informatics System for Effectiveness registry linked to Medicare claims from 2016 to 2018. Patients were required to have two AS International Classification of Diseases codes 30 or more days apart and a subsequent Medicare claim. Then, 1 year of baseline characteristics were included, after which patients were observed for fractures. First, we calculated the incidence rate of fractures. Second, we constructed logistic regression models to identify factors associated with the fracture, including age, sex, race and ethnicity, body mass index, Medicare/Medicaid dual eligibility, area deprivation index, Charlson comorbidity index, smoking status, osteoporosis, historical fracture, and use of osteoporosis treatment, glucocorticoids, and opioids.

RESULTS

We identified 1,426 adults with prevalent AS. Mean ± SD age was 69.4 ± 9.8 years, 44.3% were female, and 77.3% were non-Hispanic White. Fractures occurred in 197 adults with AS. The overall incidence rate of fractures was 76.7 (95% confidence interval [CI] 66.4-88.6) per 1,000 person-years. Older age (odds ratio [OR] 2.8, 95% CI 1.39-5.65), historical fracture (OR 5.24, 95% CI 3.44-7.99), and use of more than 30 mg morphine equivalent (OR 1.86, 95% CI 1.08-3.19) conferred increased odds of fracture.

CONCLUSIONS

In this large sample of Medicare beneficiaries with AS, increasing age, historical fracture, and use of opioids had higher odds of fracture. Men and women were equally likely to have a fracture. Because opioid use was associated with fracture in AS, this high-risk population should be considered for interventions to mitigate risk.

Abstract P668: Clinically Meaningful Weight Gain Before Menopause and Risk of Stroke

Background: Obesity is an independent risk factor for stroke. Weight gain has been associated with a higher risk of cardiovascular diseases in postmenopausal women. It is unclear, however, if weight changes before menopause have similar effects. We hypothesized that clinically meaningful premenopausal weight gain, defined as Body Mass Index (BMI) change >5%, would be associated with a higher stroke risk later in life.

Methods: Using data from the California Teachers Study, we identified women aged < 55 with no history of stroke. We used weight changes between 1995-2006 as proxy for premenopausal weight gain. We defined weight change as modest or moderate using BMI changes of 5-10% and >10% respectively. Stroke outcomes were obtained from linkage to California hospitalization records. We used Cox regression models to calculate hazard ratios with 95% confidence intervals for the association of weight change and future stroke, adjusting for vascular risk factors.

Results: Of 17,295 women included in the study, 113 had a stroke. In comparison to women who maintained a stable weight, women with moderate weight gain during premenopausal years had 2.0 times the risk of stroke. In the adjusted analysis, women with moderate weight gain had 89.6% higher risk of stroke, compared to the reference group. We found no significant association with stroke in women who had modest weight changes.

Conclusion: Moderate premenopausal weight gain significantly increased stroke risk in women. Younger women should be educated about the effects of weight gain on future brain health.

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