Study of N-acetyl-beta-D-glucosaminidase in elderly patients with iron deficiency anaemia

ABSTRACT

Little is known about renal tubular function in elderly patients with iron deficiency anaemia. To investigate renal tubular function in these patients. To achieve this aim, we compared renal tubular function in 30 asymptomatic non smoker elderly patients [over 65 years] having iron deficiency anaemia [group I] with 15 healthy age and sex matched controls [group II]. Based on their ages, group I patients were subdivided into 2 subgroups; group Ia consisted of 15 iron deficiency anaemia patients >/= 65 - 70 years while group Ib consisted of 15 iron deficiency anaemia patients above the age of 70 years. These patients were diagnosed during routine check up. Patients with known cardiac, hepatic, or renal diseases as well as cancer or other comorbid conditions were excluded from the study. Blood and urine samples were obtained for haematological and biochemical analysis. Urinary N-acetyl-beta-D-glucosaminidase [NAG], as an index of renal tubular function, was estimated by spectrophotometry. Mean urinary NAG levels were significantly higher in iron deficiency anaemia patients of both age groups than in controls [F=85. 77, p<0.001] with significantly higher mean values observed in group Ib than in group Ia patients. No statistically significant difference was observed between mean urinary NAG values in males [19 patients] and females [11 patients] [t= 0.56, p= 0.46]. In elderly iron deficiency anaemia patients of both age groups, urinary NAG values showed statistically significant negative correlation with haemoglobin levels [r=-0.673 and -0.811 at p=0.006 and <0.001 for groups Ia and Ib respectively] and were positively correlated with age [r=0.838 and 0.780 at p<0.001 and <0.001 for groups Ia and Ib respectively]. No correlation was detected between urinary NAG and haemoglobin values in either males or females [r=-0.433, p=0.064 for males and r=-0.077, p=0.821 for females]. There was no correlation between urinary NAG and serum iron, total iron binding capacity [TIBC] or serum ferritin in elderly iron deficiency anaemia patients of both age groups [r=-0.136, 0.328 and -0.070 at p=0.63, 0.232 and 0.805 respectively for group Ia] and [r=-0.229, -0.333 and 0.107 at p=0.414, 0.225 and 0.704 respectively for group Ib]. Elderly patients even with asymptomatic iron deficiency anaemia have impaired renal tubular function. Anaemia may be a contributing factor for renal impairment in such patients that is why it should be early diagnosed and treated even if no clinical disease is immediately apparent