American Diabetes Association 60th Scientific Sessions, 2000. Nephropathy.

Hypertension and Nephropathy A number of studies presented at the meeting gave insight into clinical and pathophysiological aspects of hypertension and nephropathy in patients with diabetes. Tarver-Carr et al. (abstract 783) reported 16-year follow-up analysis of 9,250 adults aged 30–74 in 1976–1980 who participated in the Second National Health and Nutrition Examination Survey (NHANES II). A total of 46 end-stage renal disease cases developed in the 521 diabetic adults, whereas 142 cases developed in those without type 2 diabetes at baseline, with cumulative incidence by age 75 of 7 vs. 3% among men and 8 vs. 0.8% among women with and without diabetes. For type 1 diabetes, Schultz and colleagues (abstracts 652 and 653) analyzed 511 patients developing diabetes before age 16 and followed for a median of 6 years. Of the patients, 63 developed microalbuminuria, showing both higher baseline albuminuria and a correlation of mean HbA1c with the rate of increase of albuminuria, which also increased at a higher rate after onset of puberty. The risk of developing microalbuminuria was doubled for female patients, tripled after onset of puberty, and increased 36% for every 1% increase in HbA1c. Tabak and Orchard (abstract 658) reported greater baseline albuminuria, higher HbA1c, longer diabetes duration, conventional treatment, younger age, male sex, and lower HDL cholesterol in females to be significant predictors of the development of microalbuminuria among 1,367 patients with type 1 diabetes in the Diabetes Control and Complications Trial (DCCT) who were initially normoalbuminuric. Thus, glycemia is an important explanation of diabetic nephropathy, but other factors must play a role in determining susceptibility. Brown et al. (abstract 187) simulated effects of glycemia and blood pressure using algorithms derived from UKPDS (U.K. Prospective Diabetes Study), Framingham, and DCCT data. The benefits of control were greater among individuals with greater baseline risk levels, with the data suggesting that blood pressure treatment may be more efficient than glycemic treatment in preventing microvascular complications and increasing life expectancy. In an important reminder of the need for hypertension treatment of patients with diabetes, Geiss et al. (abstract 188) reported data from the 1988– 1994 NHANES III, which included 1,507 adults with diagnosed diabetes; 71% had hypertension, with 71% of these aware of this and 57% treated. Only 12% had blood pressure ,130/85 and 45% had blood pressure ,140/90 mmHg. Morioka et al. (abstract 73) followed 227 patients with diabetes on hemodialysis for up to 9 years, showing a 7% increase in mortality for each 1% higher HbA1c at initiation of dialysis. Janka et al. (abstract 74) treated 463 patients on stable antidiabetic therapy with the ACE inhibitor/calcium-channel blocker combination of verapamil with trandolapril versus a combination of atenolol and chlorthalidone for 6 months. Blood pressure fell similarly from 169/96 to 150/85 and from 168/95 to 145/83, and albuminuria decreased similarly 19 vs. 26 mg/day. However, HbA1c was 7.9% before and after the former, but increased from 7.8 to 8.6% in the latter group, suggesting an adverse metabolic effect of b-blocker and/or diuretic treatment. Czupryniak and Drzewoski (abstract 411) treated 19 normotensive, normoalbuminuric patients with type 2 diabetes who did not show nocturnal lowering of blood pressure with the ACE inhibitor trandolapril (2 mg daily for 12 weeks). Blood pressure fell from 126/89 to 118/ 76. Even 2–4 weeks after discontinuation of the drug, a nocturnal blood pressure fall was restored despite return of systolic and diastolic blood pressure toward pretreatment levels. Del Prato et al. (abstract 75) assessed glomerular hemodynamics in 8 microand 9 normoalbuminuric normotensive patients with type 1 diabetes. Mean blood pressure increased by 10 mmHg in the microalbuminuric patients who switched from a lowto a highsodium diet. These patients had decreased insulin sensitivity and greater efferent arteriolar resistance and intraglomerular pressure, suggesting an effect of increased intraglomerular pressure in the pathogenesis of microalbuminuria, perhaps in turn related to insulin resistance. Strojek et al. (abstract 656) administered nonhypotensive doses of the sympathicoplegic drug moxonidine to 15 normotensive microalbuminuric patients with type 1 diabetes, showing a 27% decrease in albumin excretion. This suggests that sympathetic tone, like angiotensin II, has direct effects on renal function in diabetes in addition to those mediated by blood pressure elevation. ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●