Bone Abstracts

Systemic lupus erythematosus (SLE) is a chronic multisystem autoimmune disease that usually affects women during the childbearing ages. The disease can affect any organ system and varies in its clinical manifestations and severity between individuals. The disease course is characterized by relapses and remissions.

Because survival of SLE patients has improved dramatically over the last decades, attention is now more focused on complications of the disease and/or its treatment, that contribute to increased morbidity and mortality.

Osteoporosis and fractures are important disease complications in patients with SLE. In recent studies, a high frequency of low bone mineral density and both peripheral and vertebral fractures has been demonstrated in SLE patients. The incidence of symptomatic fractures is increased five fold in women with SLE. In addition, prevalent vertebral fractures are present in 20–26% of these relatively young patients¹.

The etiology of bone loss in SLE is supposed to be multifactorial, involving traditional osteoporosis risk factors, inflammation, metabolic factors, hormonal factors, and medication-induced adverse effects.

A recent 6 years follow-up study in Dutch SLE patients revealed, that low 25-hydroxyvitamin D serum levels at baseline, reduction of BMI and baseline use of antimalarial drugs were associated with bone loss². In addition, a dose-dependent relationship between glucocorticoid use and spine bone loss was demonstrated in this study. The results of this study have implications for daily clinical practice, because ultraviolet light intolerance (and subsequently low 25-hydroxyvitamin D levels) is highly frequent in SLE patients, antimalarials are ‘anchor drugs’ for the treatment of SLE, and the majority of SLE patients is on chronic glucocorticoid treatment.

Importantly, several risk factors associated with osteoporosis and fractures in SLE are modifiable by lifestyle measures or medication.

1. Bultink IE et al. Arthritis Rheum 54 2044-50, 2005.

2. Jacobs J et al. Osteoporos Int, 2012 (Epub ahead of print).