Thalassemia bone disease: the association between nephrolithiasis, bone mineral density and fractures

Abstract

Thalassemia bone disease is well described, but the prevalence of nephrolithiasis has not been characterized. The association between nephrolithiasis, reduced bone density, and increased fractures has been demonstrated through this retrospective study of 166 participants with transfusion-dependent thalassemia. The findings support the need for increased vigilance of kidney and bone disease in this cohort. Previous studies have revealed that thalassemia is associated with reduced bone mineral density (BMD) and fractures. Many causes are implicated including hypogonadism, growth hormone deficiency, marrow expansion, and iron overload. Nephrolithiasis is associated with reduced BMD and increased fractures in the general population. However, the prevalence of nephrolithiasis and its association with bone density and fractures have not been characterized in thalassemia. We have addressed this question by performing a retrospective cohort study of 166 participants with transfusion-dependent thalassemia who had undergone dual-energy X-ray absorptiometry between 2009 and 2011. Logistic regression modeling was used to adjust for potential confounders. We found a high prevalence of kidney stones (18.1 %) which was greater in males compared to females (28.7 vs 9.7 %, respectively). Renal stones were associated with reduced femoral neck Z-score and fractures in men after adjusting for potential confounders. These results indicate that nephrolithiasis is highly prevalent in patients with transfusion-dependent thalassemia and is significantly associated with reduced BMD and increased fractures. The findings from this study strongly support the need for ongoing surveillance of BMD, fractures, and nephrolithiasis in the management of transfusion-dependent thalassemia.