[Beta 2 microglobulin in diabetic patients. Apropos of 190 subjects]

Beta-2 microglobulin (beta 2 M) is a low molecular weight protein filtered by the renal glomerulus, then reabsorbed and metabolized at the proximal tubule. Its blood concentration is a good renal index, as it is independent from muscle mass and diet contrary to creatinine. We assayed serum beta 2 M in 190 cases of diabetes mellitus divided into 71 non-insulin-dependent and 119 insulin-dependent forms. We found no significant difference between both groups. Serum beta 2 M was not correlated with Hb A 1 C. Conversely, a highly significant positive correlation between beta 2 M and serum creatinine and a negative correlation between beta 2 M and creatinine clearance were demonstrated. Furthermore, patients with borderline serum creatinine and those with normal renal function show very significant differences in mean serum beta 2 M concentrations, thus making combined assay of both parameters advisable. On the other hand, we were unable to evaluate modifications in beta 2 M according to other complications of diabetes mellitus as vascular and neurologic involvement are very often associated with renal dysfunction.