Patients
fracture, hypogonadism, fractures, vertebral fracture, thalassemia, NTDT, osteoporosis
THALASSEMIA, EVENT, HYPOGONADISM, OSTEOPOROSIS
From a total of 106 thalassemia patients with osteoporosis in the Chiang Mai University Hematology outpatient clinic between January 2018 and September 2018, 60 patients were eligible and underwent randomization. Thirty-three patients were assigned to receive alendronate, while 27 were assigned to receive placebo. Six and four patients from the alendronate and placebo groups withdrew their consent, respectively. At 12 months, 27 patients in the alendronate group and 20 patients in the placebo group completed the follow-up visit and were included in the analysis (Study population flow.The baseline characteristics of patients were well-balanced (Patient characteristics.BMD, bone mineral density; BMI, body mass index; CBC, complete blood count; CTX, C-terminal crosslinking telopeptide of type I collagen; DFO, deferoxamine; DFP, deferiprone; DFX, deferasirox; HRT, hormone replacement therapy; IGF-1, insulin-like growth factor 1; IQR, interquartile range; P1NP, procollagen type I N-terminal propeptide; PRC, packed red cells; RBC, red blood cell; SD, standard deviation; VFA, vertebral fracture analysis; WBC, white blood cell.The mean serum vitamin D level was 30.2 ± 8.9 ng/ml, and 54.9% of patients had low serum vitamin D. Patients in the placebo group tended to have more hypogonadism but not statistically significant (14.8% vs 30.4%, p = 0.18). Low IGF-1 level was common among thalassemia patients with osteoporosis (54.9%).About 40% of patients had a history of trauma-related fracture, with a median age of 21 years (IQR 11 – 25) when they had the first fracture event. The prevalence of vertebral fractures among thalassemia patients with osteoporosis was 35.3%. Most patients were asymptomatic (11 of 18, 61.1%).Prespecified analysis comparing the characteristics between TDT and NTDT patients revealed that the TDT group had more patients with low IGF-1 level (73.5% vs 17.6%, p <0.001) compared to the NTDT group. In addition, patients in the TDT group had higher mean serum ferritin level (2,122 ± 1,310 vs 994 ± 502 μg/L, p < 0.001). TDT patients tended to have more hypogonadism than NTDT group (29.4% vs 11.8%, p=0.161). However, the mean BMD Z-score, levels of BTMs, and history of fractures were not statistically different between groups.