Background/Purpose: Osteoporosis (OP) and avascular necrosis
(AVN) are well-recognized musculoskeletal complications of systemic lupus
erythematosus (SLE) and cause morbidity.  Steroid therapy and the
underlying disease process are major contributors to these complications and
the degree to which each influences the development of OP and AVN is unclear.
Precise rates of AVN and OP are are far higher than the general population. The
aim of this study was to identify the prevalence of OP and AVN and modifiable
risk factors associated with their development in SLE. 

Methods:

A comprehensive review of published articles and unpublished abstracts
was conducted using the PubMed, EMBASE, and Cochrane databases. All articles
relating to risk factors for AVN and OP in SLE were included. Exclusion
criteria were: pediatric OP, publication with 44 or fewer SLE patients, and
studies using the same patient population. 

Results: Ten articles pertaining to AVN and 13 with OP were
included. The prevalence of OP was 12% (range 5%-23%) and osteopenia 38% (9%-50%).
Age, cumulative steroid dose, SLE damage, and low BMI were frequently reported
risk factors. Other risks in some studies included: white or non-African
Caribbean ethnicity, limited physical activity, premature ovarian failure,
decreased vitamin D, decreased osteocalcin, low C4, positive anti-Smith
antibody, and negative anti-Ro antibody. The cumulative dose of
glucocorticosteroids was not significantly related to AVN. There was no
difference in disease activity in patients who did and did not develop AVN
(p=0.7). SLE renal involvement had more AVN (OR 2.4, 95% CI 1.5,3.8). Other
risks in some studies were: cytotoxic drugs (cyclophosphamide and mycophenolate
mofetil), serositis, Raynaud’s, vasculitis, and seropositivty including anti-Smith
and antiphospholip Abs. Antimalarial drugs were not significantly protective
for AVN. Figures show some associations with AVN in SLE.

Conclusion: Several risk factors for OP and AVN were identified. Steroids
were associated with OP. Renal involvement and vasculitis are associated with
AVN.