Indicators of renal glomerular and tubular functions in patients with beta-thalassaemia major

There are limited data concerning the assessment of renal function in beta-thalassaemia major, with no study of such involvement in Omani patients. The objective of this study was to establish the pattern of renal glomerular and tubular function using traditional and specific laboratory tests in patients with beta-thalassaemia major. This cross-sectional study, from January-July 2008, included 30 patients of the Thalassaemia Clinic at the Royal Hospital, Oman, with transfusion-dependent homozygous beta-thalassaemia major. They included 15 males and 15 females, aged 16-32 years with mean +/- standard deviation of 21.23 +/- 3.42 years. The medical records were reviewed and renal function states assessed as follows: serum creatinine, estimated glomerular filtration rate [eGFR]; urea; phosphate, fractional excretion of filtered sodium [FENa]; urine albumin: creatinine index; urine beta2-microglobulin:creatinine index; tubular reabsorption of phosphate [TRP], and tubular maximum phosphate reabsorption [TmP]/GFR. All patients had eGFR >90 ml/min/1.73m2; serum creatinine <90 micro mol/L; serum urea <6.0 mmol/L, and urine albumin: creatinine <2.5 mg/mmol. Only 2 [6.7%] patients had FENa >1% and 3 [10.0%] patients had urine s2-microglobulin: creatinine >22 micro g/mmol. All patients had TRP >0.85, of whom seven [23.3%] patients had values within the range of 0.85-0.95 and 23 [76.7%] had values >0.95. Also, all patients had TmP/GFR >1.0 mmol/L, of whom only one [3.3%] patient had TmP/GFR of 1.0-1.5, and 29 [96.7%] patients had TmP/GFR >1.5 mmol/L. Finally, 24 [80%] patients had serum phosphate >1.4 mmol/L. Linear regression revealed a highly significant correlation between serum phosphate and TmP/GFR [r = 0.904, P < 0.001]. Renal function, glomerular and tubular, appears to be well preserved in beta-thalassaemia major. Almost all renal function indicators were within the recommended ranges. Raised TmP/GFR and TRP were noted in the majority of patients, reflecting an up-trend in serum phosphate and therefore increasing renal phosphate reabsorption

Serum myoglobin in patients with thyroid dysfunction

To assess the pattern of change in serum myoglobin concentration in subjects with thyroid dysfunction. Serum samples were selected from 150 subjects with suspected thyroid disorder who were referred to the Royal Hospital, Muscat, Oman. The subjects were 35 males and 115 females, aged 14-56 years with mean +/- SD of 34.3 +/- 12.7 years. They were classified on the basis of thyroid stimulating hormone [TSH] and free thyroxine [FT4] into 3 groups, each consisting of 50 subjects: hypothyroid, hyperthyroid, and euthyroid subjects. The mean serum myoglobin concentration was higher in hypothyroid patients compared to hyperthyroid and euthyroid subjects [mean +/- SD was 38.5 +/- 23.1 micro g/L in hypothyroid; 18.1 +/- 7.0microg/L in hyperthyroid; 17.4 +/- 5.7microg/L in euthyroid]. There was a significant difference in myoglobin concentration between hypothyroid and euthyroid groups [F = 36.1, p< 0.001], however, there was no significant difference between the hyperthyroid and euthyroid groups. When the mean +/- 2SD for myoglobin in euthyroid subjects was calculated, the reference range was 6-29 micro g/L. Of the hypothyroid subjects, 29 [58%] had high myoglobin and 21 [42%] had normal myoglobin level. No significant correlation was noticed between TSH or FT4 and myoglobin in all studied subjects. Raised serum myoglobin may be observed in patients with hypothyroidism. Hence hypothyroidism should be considered in the differential diagnosis of patients with raised serum myoglobin concentration