ERYTHROCYTE SODIUM-LITHIUM COUNTERTRANSPORT ACTIVITY AS A MARKER OF PREDISPOSITION TO HYPERTENSION AND DIABETIC NEPHROPATHY IN NIDDM

OBJECTIVE- To evaluate the potentiality of erythrocyte sodium-lithium countertransport activity (SLC) as a marker of predisposition to hyper tension and diabetic nephropathy in non-insulin-dependent diabetes mel litus (NIDDM). RESEARCH DESIGN AND METHODS- We examined 96 patients wi th NIDDM and 26 healthy control subjects. SLC and other data were comp ared among subgroups of the patients classified on the basis of hypert ension, family history of hypertension, and stages of nephropathy. Dat a were also analyzed by stepwise multiple regression analyses. RESULTS - SLC was significantly higher in patients with hypertension than in t hose with normotension and significantly higher in patients with a pos itive family history of hypertension than in the negative group. Furth er analysis revealed that a family history of hypertension has indepen dent influence on SLC, but hypertension itself does not. SLC was signi ficantly higher in patients with macroalbuminuria than with microalbum inuria and;higher in patients with microalbuminuria than with normoalb uminuria. In stepwise multiple regression analyses, a family history o f hypertension was the most important determinant of SLC, and SLC was the most important determinant of nephropathy. CONCLUSIONS- These data suggest that SLC strongly reflects a predisposition to hypertension a nd that it can be a useful marker of diabetic nephropathy in NIDDM.