[A study on inactive renin in the plasma of patients with diabetes mellitus]

Plasma inactive renin concentration (IRC) was determined in 92 diabetic patients with or without chronic diabetic complications, 23 non-diabetic patients with renal failure and 36 normal subjects. IRC of the diabetics was higher than that of normal persons. With the Pearson's correlation analysis, IRC of the diabetics correlated with duration of diabetes, degrees of chronic complications (nephropathy, retinopathy and neuropathy), but not with age of patient, HbA1c or mean blood pressure. The stepwise logistic analysis revealed the relation of neuropathy to mean blood pressure, serum creatinine concentration and duration of diabetes, retinopathy to mean blood pressure, duration of diabetes and serum beta 2-microglobulin and nephropathy to IRC and urinary NAG/Cr ratio. In addition, IRC was dependent on nephropathy but not on retinopathy or neuropathy. IRC in diabetics was high even in diabetics without albuminuria (group I) and significantly increased in diabetics with albuminuria but without increased serum creatinine level (group II) and more marked high levels were observed in diabetics with increased serum creatinine concentrations (group III). However, IRC of the non-diabetic patients with renal failure was not elevated, therefore, the increased IRC in nephropathy is likely to be specific to diabetic nephropathy. The correlation of other factors to increased IRC level seem to be due to nephropathy concomitant to these factors. Therefore, the increased level of IRC in diabetics is intimately connected to renal change in diabetes but whether it is the cause or result of nephropathy remains to be elucidated. It is concluded that the determination of IRC in diabetic patients was an effective means of assessment or forecast of nephropathy.