Background Sarcoidosis often involves pathological dysregulation of dependent factors of bone metabolism, e.g. calcitriol /calcium, and administration of high dose glucocorticoids (GCs) leading to low bone mineral density (LBMD). Traditional risk factors for LBMD include advancing age, female sex, low body mass index (BMI), smoking, white race and GCs. LBMD in sarcoidosis is presumed but not yet described.
Methods A retrospective chart review of biopsy-diagnosed patients with sarcoidosis for >1 year extracted and compared variables of prevalence, age (at chart review), sex, race, smoking status and designation of LBMD defined as osteopenia or osteoporosis with a T-score of ≤ -1 on DXA. Calculations were performed by non-parametric analyses using Fisher's exact for categorical data and Mann Whitney tests for continuous variables.
Results 269 charts were reviewed and 109 had documentation of biopsy. Of these 109, 61 patients (86.9% Black) had documentation of DXA, 38 (62.3%) with LBMD (30 with osteopenia and 8 with osteoporosis). Although patients with BMI ≥30 had a significantly lower incidence of LBMD vs. those with BMI <30, LBMD incidence exceeded reported in CDC data for overweight subjects. No differences (table) were seen in incident LBMD in patients age ≥ vs <65, in ever vs never smokers (no significant age difference between groups), nor in males vs females (despite females being significantly older than males with median 54 and 48 respectively).
Conclusions Factors protective against LBMD in the general population were not demonstrated in this retrospective sarcoidosis predominantly black cohort. A lower risk of LBMD was not conferred by age <65, male gender, or non-smoking status. While BMI appeared to confer protection, the prevalence in obese sarcoidosis patients supersedes that in CDC reported data. These trends suggest an abnormal signal of incident LBMD in this population differing from the general population. Lack of uniformity of documentation inherent in retrospective methods limits the assessment of important associative and causative influences such as duration and dose of GCs, biomarkers of bone metabolism (e.g. calcium, calcitriol, etc) and fracture risk which will be examined in our prospective sarcoid registry. Nevertheless these findings are important and support increased vigilance in GC use and perhaps consideration to initiate GC sparing agents earlier in the disease course, as well as routine DXA screening in sarcoidosis.
Acknowledgements This research was funded by grant #T35HL105350 from the National Heart, Lung and Blood Institute.
Disclosure of Interest M. Walker: None declared, A. Janot: None declared, H. Grewal: None declared, M. Yu: None declared, M. Lammi: None declared, L. A. Saketkoo Grant/research support from: ACR/EULAR Exchange Awardee