Bone Disease in Connective Tissue Disease/Systemic Lupus Erythematosus

This article reviews recent advances in the research of the mechanisms of bone loss, as well as clinical features, economic impact and therapeutic implications of osteoporosis and fractures in patients with systemic lupus erythematosus (SLE) as an illustration of bone disease in a complex systemic autoimmune connective tissue disease. Recent studies demonstrated an increased incidence of osteoporosis and peripheral and vertebral fractures in patients with SLE. The aetiology of bone loss in SLE is multifactorial, including clinical osteoporosis risk factors, systemic inflammation, serological factors, metabolic factors, hormonal factors, possibly genetic factors and medication-induced adverse effects. The incidence of symptomatic fractures in patients with SLE is increased 1.2-4.7-fold and age, disease duration, glucocorticoid use, previous cyclophosphamide use, seizures and a prior cerebrovascular event have been identified as important risk factors. Moreover, a high prevalence of morphometric vertebral fractures was demonstrated, while one in three of these patients has normal bone density, which finding points to the multifactorial aetiology of fractures in SLE. The clinical consequences and economic burden of osteoporosis and fractures as glucocorticoid treatment-related adverse events and the high frequency of glucocorticoid therapy underline the importance of reducing glucocorticoid treatment and prescribing steroid-sparing agents. No data on fall risk and its determinants and the relationship with the occurrence of fractures in patients with SLE are currently available. Fall risk might be increased in lupus patients for several reasons. In addition, the recently reported high prevalence (20%) of frailty in SLE patients may contribute to the increased fracture incidence. Therefore, the relationships between fall risk, frailty and fracture occurrence in SLE might be interesting subjects for future studies.