Factors associated with bone mineral density loss in patients with spondyloarthropathies: A 4-year follow-up study

Objective: To explore the relationship between laboratory, functional, disease activity markers and bone mineral density (BMD) loss in patients with spondyloarthropathies (SpAs). Methods: A cohort of 41 SpA patients were followed up for 4 years. Disease activity indices, spinal mobility and laboratory tests, BMD using were monitored at the baseline and 4- year follow- up. The 4% BMD loss at either of the proximal femurs was defined as significant. Results: Over the 4- year study period, 27% of SpA patients experienced femoral BMD loss. Baseline BMD > 0.85 g/cm(2) (p = 0.011) was the baseline factor associated with BMD loss at 4-year follow- up. Several clinical and functional tests were helpful in identifying the BMD loss at follow- up: CRP > 15.6 mg/L (sens. 91%, spec. 70%), ESR > 29 mm/h (sens. 82%, spec. 73%), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) > 4.75 (sens. 91%, spec. 62%). At follow- up anti-TNF alpha treatment history, stable or improved lateral flexion and intermalleolar distance (NPV, accordingly, 95%, 88% and 87%), made BMD loss unlikely. Deterioration of the physician assessment of global disease activity (PAGDA) score from baseline to follow- up was a remarkable predictor of BMD loss (PPV = 0.83), while stable or improved score excluded the BMD loss (NPV = 0.83). According to multiple logistic regression analysis, baseline BMD value and follow- up CRP levels, when considered together, identify BMD status correctly in 85% of SpA patients (Nagelkerke R-2 = 0.676). Conclusion: Baseline BMD, anti-TNF alpha treatment, PAGDA score, spinal mobility tests and disease activity markers are useful factors in predicting the BMD loss in SpA patients and can provide surrogate information on BMD status. (C) 2015 Lithuanian University of Health Sciences. Production and hosting by Elsevier Sp. z o.o.