Myositis

Elevated Risk for Osteoporosis and Fracture in Patients With Inflammatory Myositis

Morgan E. Meissner
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Osteoporosis is diagnosed in individuals with a bone mineral density (BMD) T-score of −2.5 or less.11 Patients with RA are twice as likely as the general population to develop generalized osteoporosis.2 Although osteoporosis is more common in women with RA, men are also at risk.12,13 In RA, BMD loss is greater at the peripheral bones than the axial skeleton.2 Data show 17% to 32% of patients with RA have BMD loss at the lumbar spine, and 15% to 36% have BMD loss at the hip.1 Periarticular and generalized osteoporosis may share a similar mechanism. Glucocorticoid use accelerates BMD loss, especially in the first 3 to 6 months.18 Disease duration and activity are strong predictors of osteoporosis risk, but evidence of bone loss is also seen in patients with early, asymptomatic RA.1,2 Another risk factor is sarcopenia, which affects more women than men with RA.1 Patient-related risk factors include postmenopausal status/age, low BMI, immobility, and family history of osteoporosis.1,2,5 Anti-TNF-α blockade appears to reduce the rate of generalized bone loss, possibly by restoring equilibrium between bone resorption and formation.2

Osteoporosis is diagnosed in individuals with a bone mineral density (BMD) T-score of −2.5 or less.11 Patients with RA are twice as likely as the general population to develop generalized osteoporosis.2 Although osteoporosis is more common in women with RA, men are also at risk.12,13 In RA, BMD loss is greater at the peripheral bones than the axial skeleton.2 Data show 17% to 32% of patients with RA have BMD loss at the lumbar spine, and 15% to 36% have BMD loss at the hip.1 Periarticular and generalized osteoporosis may share a similar mechanism.

Glucocorticoid use accelerates BMD loss, especially in the first 3 to 6 months.18 Disease duration and activity are strong predictors of osteoporosis risk, but evidence of bone loss is also seen in patients with early, asymptomatic RA.1,2 Another risk factor is sarcopenia, which affects more women than men with RA.1 Patient-related risk factors include postmenopausal status/age, low BMI, immobility, and family history of osteoporosis.1,2,5 Anti-TNF-α blockade appears to reduce the rate of generalized bone loss, possibly by restoring equilibrium between bone resorption and formation.2

Researchers assessed and compared the fracture risk and prevalence of osteoporosis in patients with idiopathic inflammatory myopathy and rheumatoid arthritis.

Patients with inflammatory myositis are at increased risk for osteoporosis and fracture, according to study results published in BMC Musculoskeletal Disorders.

Researchers aimed to determine the prevalence of low bone mineral density (BMD) and fracture risk in patients with inflammatory myositis compared with those with rheumatoid arthritis (RA).

Data were obtained for 52 patients with myositis (82.7% women) and 43 patients with RA (95.3% women) treated at the National Myositis Center at the University of Debrecen in Debrecan, Hungary. Fracture risk was assessed using the Fracture Risk Assessment Tool (FRAX), and physical function and quality of life were evaluated using the FRAX Health Assessment Questionnaire and Short Form-36 questionnaire, respectively.

Researchers identified osteopenia in 60% of patients with myositis and 39.5% of patients with RA. Osteoporosis occurred significantly more frequently in patients with myositis (13.5%) than those with RA (7%; P =.045). Without accounting for BMD, femoral neck fracture risk was found to be significantly higher in patients with RA vs myositis (15.58% vs 9.68%; P =.008). Similar results were observed for other major fracture risk (6.23% vs 3.06%; P =.022). This difference was attenuated after accounting for differences in BMD and was further decreased after correcting for glucocorticoid use.

Overall 40 patients with myositis and 35 with RA received vertebral x-ray examinations. A total of 194 vertebral fractures were identified in 54 patients, including 115 fractures in 30 patients with myositis and 79 fractures in 24 patients with RA; however, the difference in fracture frequency was not significantly different between the groups. Compared with patients without fractures, patients with vertebral fractures were older in both patients with myositis (mean age, 55.4 vs 62.83 years; P =.034) and RA (mean age, 52.0 vs 63.25; P =.022). Age was an independent predictor of vertebral fracture in patients with myositis (P =.042).

Physical function scores were proportional to the number of vertebral fractures in patients with myositis (correlation coefficient [r]=0.457; P =.008) and RA (r=0.376; P =.041). Decreases in quality of life scores were also proportional to the number of vertebral fractures in myositis (r=0.538; P <.001).

Investigators noted that the small number of participants in the study obtained from a single center in Hungary may limit the generalizability of results.

“It can be concluded that osteoporosis and consequential fractures in myositis are common and probably underestimated, and that their examination is often neglected,” the researchers concluded. “Therefore, it would be important to pay greater attention to the recognition of low BMD and high fracture risk and adherence to preventive measures.”

Reference

Vincze A, Bodoki L, Szabó K, et al. The risk of fracture and prevalence of osteoporosis is elevated in patients with idiopathic inflammatory myopathies: cross-sectional study from a single Hungarian center. BMC Musculoskelet Disord. 2020;21(1):426.

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