Issue 141 Item 4 Smoking Increases Risk of Diabetic Nephropathy Despite ACE Inhi

Cigarette smoking increases oxidant stress and thereby progressive renal injury in patients with type 2 diabetes. In type 2 diabetics being treated with ACE inhibitors, cigarette smoking and increased urine albumin excretion (UAE) are linked as predictors of nephropathy progression, researchers at Texas Tech University have determined

The findings are reported in the American Journal of Kidney Diseases for January. Senior researcher Dr. Donald E. Wesson said, “that the study suggests that cigarette smoking increases the risk for a diabetic to develop kidney failure.” He noted that ACE inhibition "successfully prevents kidney failure in most nonsmoking diabetics."

Dr. Wesson and colleagues prospectively followed 84 hypertensive patients with type 2 diabetes–31 cigarette smokers and 53 nonsmokers–whose hypertension was treated with an ACE inhibitor-containing regimen.

At study entry, the mean albumin-creatinine (alb-cr) ratio did not differ between smokers and nonsmokers, but over an average of 64 months of follow-up, the mean increase was significantly greater in smokers than in smokers.

The rate of progression was low and fairly stable when the entry alb-cr ratio was <300, and it increased markedly as the ratio increased over that value. Smoking predicted progression in the subgroup of patients with greater UAE (alb-cr ratio >300).

Furthermore, the increase in the alb-cr ratio correlated well with progression to nephropathy, the Texas team calculated.

"The present studies are consistent with the hypothesis that cigarette smoking increases oxidant stress and thereby progressive renal injury in patients with type 2 diabetes that is manifest by increased UAE," the researchers conclude. Am J Kidney Dis 2003;41:13-21.