7 Mædica A Journal of Clinical Medicine, Volume1 No.1 2006 Bone mineral density in patients with ankylosing spondylitis Laura MUNTEAN, MD, Siao-pin SIMON, MD, PhD, Calin R. BOLOSIU, MD, PhD, Simona REDNIC, MD, PhD, Laura DAMIAN, MD, PhD, Horatiu D. BOLOSIU, MD, PhD Research Centre for Rheumatic Diseases, Department of Rheumatology, University of Medicine and Pharmacy “Iuliu Hatieganu“ Cluj Napoca, Romania ABSTRACT Objective: To determine bone mineral density (BMD) and the frequency of osteoporosis (OP) and osteopenia in ankylosing spondylitis (AS). A second objective was to investigate the relationship between BMD and clinical parameters. Methods: Twenty-nine patients (23 male, 6 pre-menopausal female) were compared with 29 sex- and age-matched controls. BMD was evaluated at the lumbar spine and femoral neck by dual energy X-ray absorbtiometry (DEXA) using a DPX-alpha (Lunar-General Electric). Results: In AS patients BMD was significantly reduced in both lumbar spine 1.08 ± 0.22 g/cm 2 (T = -1.23 ± 1.80) and femoral neck 0.88 ± 0.15 g/cm 2 (T= -1.30 ± 1.31) as compared with controls (1.16 ± 0.11 g/cm 2 [T= – 0.49 ± 0.80], respectively 0.96 ± 0.13 g/ cm 2 [T= – 0.65 ± 1.04]) (all p < 0.05). According to the WHO definition, spine and hip OP was diagnosed in 34.48% and 20.68% AS patients respectively, with an additional 20.68% and 41.37% having osteopenia. We found no correlation between BMD and disease duration. Only spine BMD correlated with disease activity, as evaluated by erythrocyte sedimentation rate and serum C-reactive protein levels (r = – 0. 55, respectively – 0.48; both p < 0.01). In the subgroup analysis according to the presence or absence of syndesmophytes, the patients were grouped in advanced and mild AS categories, respectively. The mean BMD at the lumbar spine and femoral neck of patients with mild and advanced AS was similar (all p > 0.05). In the advanced AS patients, osteopenia and OP frequency was higher than in the mild AS patients, but the difference was not statistically significant (p > 0.05). Conclusions: These results confirm that the majority of AS patients have decreased BMD values at both the lumbar spine and femoral neck. OP can be observed in early stages of the disease. The similar frequency of OP in mild and advanced AS suggests that immobility does not have an important role in pathogenesis. Patients with active disease are especially at risk for developing OP. Key words: ankylosing spondylitis, osteoporosis, bone mineral density INTRODUCTION A nkylosing spondylitis (AS) is an inflammatory rheumatic disease characterized by spine and sacroiliac joint involvement that mainly affects young male sub- jects. Its clinical spectrum varies from a simple pelvic involvement (sacroiliitis) to a severe multisystemic and progressive disease (1). Syndesmophytes, which are due to new bone formation, are considered to be a hallmark of the disease. In parallel with this process, a reduction in bone formation also occurs. The presence of osteoporosis (OP) in AS patients has been confirmed by numerous researchers. For several years it has been established that bone mineral density (BMD) loss occurs early in the AS disease course. However, the patho- genesis of OP remains controversial. (2). The clinical significance in OP lies in development of fractures. Osteoporotic vertebral fractures are relatively common, but frequently unre- cognized complications of AS, that can contri- butes to spinal pain and deformity of AS pa- tients. Fractures frequently occurred as a re- sult of minimal trauma and were associated with severe neurological deficits in a high pro- portion of patients (3, 4). The aims of this study were to determine bone mineral density (BMD) and the fre- quency of OP and osteopenia in AS and whe- ther BMD is correlated to duration and disease activity. ! ORIGIN RIGIN RIGIN RIGIN RIGINAL AL AL AL AL PAPERS APERS APERS APERS APERS : : : : : CLINIC CLINIC CLINIC CLINIC CLINICAL AL AL AL AL OR OR OR OR OR BASIC ASIC ASIC ASIC ASIC RESEAR RESEAR RESEAR RESEAR RESEARCH Mædica - a Journal of Clinical Medicine