MATERIALS AND METHODS: A retrospective study was carried out on 318 subjects with hypochromic anaemia, which comprised 162 IDA and 156 thalassaemia trait subjects with α-thalassemia, β-thalassemia and HbE trait. Optimal cut-off value, sensitivity and specificity of M/H ratio for thalassaemia trait discrimination was determined using Receiver Operating Characteristic (ROC) analysis.
RESULTS: Subjects with thalassaemia trait showed higher MicroR compared to IDA ( p< 0.001) while subjects with IDA demonstrated higher Hypo-He than thalassaemia trait (p < 0.001). M/H ratio was significantly higher in thalassaemia trait compared to IDA, with medians of 3.77 (interquartile range: 2.57 - 6.52) and 1.73 (interquartile range: 1.27 - 2.38), respectively (p < 0.001). M/H ratio ≥ 2.25 was the optimal cut-off value for discriminating thalassaemia trait from IDA in hypochromic anaemia, with the area under ROC curve (AUC) of 0.83, sensitivity of 80.8% and specificity of 71.6%.
CONCLUSIONS: M/H ratio is a useful discriminant index to distinguish thalassaemia trait from IDA in hypochromic anaemia prior to diagnostic analysis for thalassaemia confirmation. High M/H ratio is suggestive of thalassaemia trait than of IDA. However, more studies are required to establish the role of M/H ratio as a screening tool for thalassaemia discrimination in hypochromic anaemia.
EVIDENCE ACQUISITION: A systematic search of all English-language medical literature published from 1980 till May 2016 using PubMed, Embase and Ovid was performed. Nine observational studies were evaluated after fulfilling the inclusion and exclusion criteria.
EVIDENCE SYNTHESIS: A total of 547 patients were examined. All studies used vitamin D2/D3 or calcifediol (25-hydroxyvitamin D3), There was significant improvement of serum 25(OH)D with unchanged serum iPTH level after vitamin D replacement, with pooled d+: 3.10 (95% CI 2.25 to 3.95), P<0.01 and pooled d+: 0.82 (95% CI -0.35 to 1.98), P=0.16 respectively. There was neither worsening of the pre-existing hypercalcemia (pooled d+: -0.27 [95% CI -1.09 to 0.64, P=0.56]) nor hypercalciuria (pooled d+: 3.64 [95% CI -0.55 to 7.83, P=0.09]). Two studies assessed in this meta-analysis reported unchanged bone density with vitamin D replacement.
CONCLUSIONS: Vitamin D replacement in subjects with mild PHPT and coexistent vitamin D deficiency improved serum 25(OH)D level without worsening of pre-existing hypercalcemia or hypercalciuria. Well-designed multicenter randomized controlled trials examining pre- and postoperative outcomes of vitamin D therapy in patients with different severities of PHPT and vitamin D inadequacy are warranted to elucidate the most appropriate vitamin D treatment protocol and determine the long-term safety concerns.