Susceptibility to diabetic nephropathy may be related to a predisposition to arterial hypertension. We have studied the activity of sodium-lithium countertransport in red cells, a marker of risk for essential hypertension, in white European adults with insulin-dependent diabetes and diabetic nephropathy, a matched group of patients with diabetes without renal disease, and nondiabetic patients with renal disease. Measures of metabolic control and concentrations of plasma free insulin and growth hormone were similar in the two diabetic groups. The degree of impairment in renal function was similar in the diabetic and nondiabetic patients with renal disease. Body-mass index and plasma potassium concentrations were similar in all three groups. Diastolic blood pressure was elevated to a similar degree in the two groups with renal disease, as compared with that in the diabetic patients without renal disease. The rates of sodium-lithium countertransport in red cells were significantly higher in the diabetic patients with renal disease (mean +/- SD, 0.55 +/- 0.19 mmol of lithium per liter of red cells per hour) than in the diabetic patients without renal disease (0.33 +/- 0.16; P less than 0.005) and in the nondiabetic patients with renal disease (0.31 +/- 0.14; P less than 0.001). Predisposition to hypertension, as indicated by elevated sodium-lithium countertransport activity in red cells, may serve as a marker for the risk of renal disease in patients with insulin-dependent diabetes.

Associations between overnight urinary albumin excretion rate and prevalent coronary heart disease and its major risk factors were examined in a cross-sectional study of 141 Type 2 (non-insulin-dependent) diabetic patients. Mean albumin excretion rate was higher in men (geometric mean 13.5 micrograms/min; 95% confidence interval 10.3-17.6) than women (7.5 micrograms/min; 5.7-9.8, p less than 0.01). In diabetic men and women mean albumin excretion rate was higher in those with electrocardiographic and/or symptomatic evidence of coronary heart disease than in those without (men, 23.1 micrograms/min; 95% confidence interval 13.7-39.0 versus 10.6 micrograms/min; 7.9-14.2, p less than 0.01, women, 13.7 micrograms/min; 8.0-23.5 versus 5.4 micrograms/min; 4.2-6.8, p less than 0.01). Multiple logistic regression analysis was used to allow for confounding between variables. In the diabetic group as a whole, raised albumin excretion rate (p less than 0.001), gender (p less than 0.05) and systolic blood pressure (p = 0.06) entered the "best" model for coronary heart disease prediction. In women, albumin excretion rate alone (p less than 0.01) and in men albumin excretion rate (p less than 0.01) and age (p = 0.05) entered the "best" models. We conclude that albumin excretion rate is significantly associated with coronary heart disease morbidity after taking into account the confounding effects of raised blood pressure and other cardiovascular risk factors.

Non-insulin-dependent diabetes mellitus is strikingly common in British Indians, but their susceptibility to diabetic complications is unknown. The ratio of albumin to creatinine concentrations was measured in samples of the first urine voided in the morning in 154 Indian and 82 Europid patients with non-insulin-dependent diabetes and in a control group of 129 non-diabetic Indians. The ratio was significantly higher in the Indian patients than in the Europid patients and the Indian controls. There were no significant correlations between the logarithm of the albumin: creatinine ratio and age, known duration ofdiabetes, haemoglobin A1 concentration, or body mass index within either diabetic group. Hypertension and raised albumin:creatinine ratio were significantly associated, and significant correlations were seen between the logarithm of the albumin:creatinine ratio and systolic and diastolic blood pressures in the Indian but not the Europid diabetics.

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