Unexpected severe incident vertebral fractures in patients with systemic lupus erythematosus: comment on the article by Zhu et al

Osteoporosis in Rheumatic Diseases

Osteoporosis is a chronic disease characterized by an increased risk of fragility fracture. Patients affected by rheumatic diseases are at greater risk of developing osteoporosis. The purpose of the present review is to discuss the pathogenesis, epidemiology, and treatment of osteoporosis in patients affected by rheumatic diseases with special focus for rheumatoid arthritis, psoriatic arthritis, spondyloarthritis, systemic lupus erythematosus, systemic sclerosis, vasculitides, Sjogren syndrome, and crystal-induced arthritis.

Lupus and fractures

PURPOSE OF REVIEW

The article reviews recent advances in the research of fractures in patients with systemic lupus erythematosus (SLE), highlighting their clinical, scientific, and economic impact.

RECENT FINDINGS

Recent studies demonstrated an increased incidence of osteoporosis and symptomatic fractures in patients with SLE and age, disease duration, disease severity, and glucocorticoid use are important risk factors. A high prevalence of vertebral fractures was demonstrated, while one in three of these patients has normal bone density, which illustrates the multifactorial cause of fractures in SLE. Screening for vertebral fractures is important, as they often occur asymptomatically, but are associated with a reduced quality of life, increased future fracture risk, an increased mortality risk, and may have therapeutic implications. A recently developed Delphi consensus revealed the high economic burden of fractures as a glucocorticoid-related adverse event in SLE, whereas the majority of patients use glucocorticoids.

SUMMARY

Recent studies revealed an increased incidence of symptomatic fractures and a relatively high prevalence of vertebral fractures in patients with SLE, and provided new insights into their multifactorial aetiology. The clinical consequences and high economic burden of fractures as glucocorticoid-related adverse events underline the importance of reducing glucocorticoid therapy and use of steroid-sparing agents.

Systemic lupus erythematosus and fractures

Since survival of patients with systemic lupus erythematosus (SLE) has improved over the past decades, increasing attention is focused on complications of the disease. Osteoporosis and fractures contribute to damage in the second most frequently involved organ system in SLE: the musculoskeletal system. Recent studies have reported a high frequency of reduced bone mineral density in SLE, and an increased risk of peripheral and vertebral fractures. The incidence of symptomatic fractures is increased 1.2-4.7-fold in patients with SLE. A large population-based study on 4343 patients with SLE and 21 780 age-matched and sex-matched controls, demonstrated previous glucocorticoid use and longer disease duration as important risk factors for symptomatic fractures in SLE. Prevalent vertebral fractures are demonstrated in 18-50% of these relatively young patients, and one in three of these patients has normal bone density. The aetiology of bone loss in SLE is supposed to be multifactorial, involving clinical osteoporosis risk factors, systemic inflammation, serological factors, metabolic factors, hormonal factors, medication-induced adverse effects and, possibly, genetic factors. A 6-year follow-up study on Dutch patients with SLE revealed that low 25-hydroxyvitamin D serum levels, low body mass index and baseline use of antimalarials were associated with bone loss. In addition, a dose-dependent relationship between glucocorticoid use and bone loss was demonstrated in longitudinal studies in SLE. These findings have implications for daily clinical practice, because vitamin D insufficiency is highly frequent in SLE, antimalarials are regarded as 'anchor drugs' for therapy and the majority of patients with SLE are on chronic glucocorticoid treatment.