Protein intake and urinary albumin excretion rates in the EURODIAB IDDM Complications Study

For people with insulin-dependent diabetes mellitus (IDDM) renal disease represents a life-threatening and costly complication. The EURODIAB IDDM Complications Study, a cross-sectional, clinic-based study, was designed to determine the prevalence of renal complications and putative risk factors in stratified samples of European individuals with IDDM. The present study examined the relationship between dietary protein intake and urinary albumin excretion rate (AER). Food intake was assessed centrally by a standardized 3-day dietary record. Urinary AER was determined in a central laboratory from a timed 24-h urine collection. Complete data were available from 2696 persons with IDDM from 30 centres in 16 European countries. In individuals who reported protein consumption less than 20% of total food energy intake, mean AER was below 20 microg/min. In those in whom protein intake constituted more than 20%, mean AER increased, a trend particularly pronounced in individuals with hypertension and/or poor metabolic control. Trends reached statistical significance for intakes of total protein (% of energy, p = 0.01) and animal protein (% of energy, p = 0.02), while no association was seen for vegetable protein (p = 0.83). These findings support the current recommendation for people with diabetes not to exceed a protein intake of 20% of total energy. Monitoring and adjustment of dietary protein appears particularly desirable for individuals with AER exceeding 20 microg/min (approximately 30 mg/24h), especially when arterial pressure is raised and/or diabetic control is poor.

Differences in mortality and morbidity in African Caribbean and European people with non-insulin dependent diabetes mellitus: results of 20 year follow up of a London cohort of a multinational study

OBJECTIVE

To examine differences in morbidity and mortality due to non-insulin dependent diabetes in African Caribbeans and Europeans.

DESIGN

Cohort study of patients with non-insulin dependent diabetes drawn from diabetes clinics in London. Baseline investigations were performed in 1975-7; follow up continued until 1995.

PATIENTS

150 Europeans and 77 African Caribbeans with non-insulin dependent diabetes.

MAIN OUTCOME MEASURES

All cause and cardiovascular mortality; prevalence of microvascular and macrovascular complications.

RESULTS

Duration of diabetes was shorter in African Caribbeans, particularly women. African Caribbeans were more likely than the Europeans to have been given a diagnosis after the onset of symptoms and less likely to be taking insulin. Mean cholesterol concentration was lower in African Caribbeans, but blood pressure and body mass index were not different in the two ethnic groups. Prevalence of microvascular and macrovascular complications was insignificantly lower in African Caribbens than in Europeans. 59 Europeans and 16 African Caribbeans had died by the end of follow up. The risk ratio for all cause mortality was 0.41 (95% confidence interval 0.23 to 0.73) (P = 0.002) for African Caribbeans v Europeans. This was attenuated to 0.59 (0.32 to 1.10) (P = 0.1) after adjustment for sex, smoking, proteinuria, and body mass index. Further adjustment for systolic blood pressure, cholesterol concentration, age, duration of diabetes, and treatment made little difference to the risk ratio. Unadjusted risk ratio for cardiovascular and ischaemic heart disease were 0.33 (0.15 to 0.70) (P = 0.004) and 0.37 (0.16 to 0.85) (P = 0.02) respectively.

CONCLUSIONS

African Caribbeans with non-insulin dependent diabetes maintain a low risk of heart disease. Management priorities for diabetes developed in one ethnic group may not necessarily be applicable to other groups.

Management of non-insulin-dependent diabetes mellitus. The United Kingdom experience

Care of persons with non-insulin-dependent diabetes mellitus (NIDDM) in the United Kingdom resembles that in the United States. However, health care practice in Europe is being influenced by the Saint Vincent Declaration, the joint European World Health Organization-International Diabetes Federation initiative, which emphasizes prevention of diabetic complications. In recent years, the responsibility for care for NIDDM has shifted in the United Kingdom to general practice teams. The effect of this shift on the quality of care and the coordinating and educational role of local diabetes specialist teams is discussed, as is the importance of an individualized "menu" of care for each patient. This menu aims for optimum blood glucose level control as well as detection and correction of risk factors for diabetic complications. The pervasive and dangerous notion of NIDDM as a "mild" disease must be corrected. The importance of systematic auditing of process and outcomes in diabetes care is emphasized, as is the need for regular data acquisition, aggregation, and analysis to achieve continuous improvement in the quality of care. Although patient-health professional encounters are the core of good diabetes care, the need for larger-scale appraisal on a local, regional, and national basis is now apparent.

Resistance to metabolic actions of insulin and its role in hypertension

Insulin resistance and hyperinsulinemia have been postulated to be important in raising blood pressure in obese as well as lean hypertensive individuals. However, cause-and-effect relationships among these variables have not been clearly established. The three most widely used methods to assess insulin resistance in vivo (fasting plasma insulin, glucose disposal after a glucose load, or glucose disposal during a hyperinsulinemic euglycemic clamp) may provide different estimates of insulin resistance under various physiological and pathophysiological conditions. Fasting hyperinsulinemia may reflect mainly hepatic insulin resistance, whereas impairment of glucose disposal indicates resistance to the metabolic effects of insulin in skeletal muscle. The importance of these different sites of insulin resistance in the etiology of cardiovascular diseases, however, is still unclear. Although hyperinsulinemia and insulin resistance have been speculated to cause hypertension, most of the evidence supporting this hypothesis has come either from correlation studies or from short-term studies of the cardiovascular, renal, and sympathetic effects of insulin. The few long-term studies that have been conducted in dogs and in humans do not support the insulin concept of hypertension. In fact, these studies suggest that the vasodilator actions of insulin tend to reduce, rather than elevate, blood pressure. Correlations between insulin resistance, hyperinsulinemia, and hypertension do not appear to be explainable by the concept that insulin resistance occurs secondary to hypertension. Obesity may be a key factor in explaining these relationships; weight gain appears to cause insulin resistance, compensatory hyperinsulinemia, and hypertension through parallel, but not necessarily linked, mechanisms. However, insulin resistance and compensatory hyperinsulinemia may contribute to increased risk of other cardiovascular diseases associated with hypertension, such as coronary artery disease.

The Diabetes Control and Complications Trial (DCCT)

The Diabetes Control and Complications Trial (DCCT) provided much information towards settling the long-running controversy about the effectiveness of improving control of diabetes on the risk of its major complications. With the appearance or the advance of clinically significant retinopathy as its major outcome variable, DCCT randomised 1,441 insulin-dependent diabetic patients to conventional or intensified control groups. In both primary prevention and secondary intervention arms of the trial, intensified control reduced retinopathy risk by half or more, and also reduced nephropathy and neuropathy risks--however, risk of severe hypoglycaemic episodes was increased about three-fold. By contrast, there were no differences in quality of life, neurocognitive or emotional assessments between the two groups. The application of trial findings to 'real life' care is considered.

Treatment of diabetic neuropathy with gamma-linolenic acid. The gamma-Linolenic Acid Multicenter Trial Group

OBJECTIVE

To compare the effects of placebo and GLA on the course of mild diabetic neuropathy over 1 yr.

RESEARCH DESIGN AND METHODS

We entered 111 patients with mild diabetic neuropathy from seven centers into a randomized, double-blind, placebo-controlled parallel study of GLA at a dose of 480 mg/day. MNCV, SNAP, CMAP, hot and cold thresholds, sensation, tendon reflexes, and muscle strength were assessed by standard tests in upper and lower limbs.

RESULTS

For all 16 parameters, the change over 1 yr in response to GLA was more favorable than the change with placebo, and for 13 parameters, the difference was statistically significant. Sex, age, and type of diabetes did not influence the result, but treatment was more effective in relatively well-controlled than in poorly-controlled diabetic patients.

CONCLUSIONS

GLA had a beneficial effect on the course of diabetic neuropathy.

Prospective study of microalbuminuria as predictor of mortality in NIDDM

Retrospective studies of patients with non-insulin-dependent diabetes mellitus (NIDDM) have suggested that microalbuminuria predicts early all-cause (mainly cardiovascular) mortality independently of arterial blood pressure. These findings have not been confirmed in prospective studies, and it is not known whether the predictive power of microalbuminuria is independent of other major cardiovascular risk factors. During 1985-1987, we examined a representative group of 141 nonproteinuric patients with NIDDM for the prevalence of coronary heart disease and several of its established and putative risk factors, including raised urinary albumin excretion (UAE) rate. Thirty-six patients had microalbuminuria (UAE 20-200 micrograms/min), and 105 had normal UAE (less than 20 micrograms/min). At follow-up, an average of 3.4 yr later, 14 patients had died. There was a highly significant excess mortality (chiefly from cardiovascular disease) among those with microalbuminuria (28%) compared to those without microalbuminuria (4%, P less than 0.001). In univariate survival analysis, significant predictors of all-cause mortality included microalbuminuria (P less than 0.001), hypercholesterolemia (P less than 0.01), hypertriglyceridemia (P less than 0.05), and preexisting coronary heart disease (P less than 0.05). The predictive power of microalbuminuria persisted after adjustment for the effects of other major risk factors (P less than 0.05). We conclude that microalbuminuria is a significant risk marker for mortality in NIDDM, independent of the other risk factors examined. Its presence can be regarded as an index of increased cardiovascular vulnerability and a signal for vigorous efforts at correction of known risk factors.

Glomerular structure in type-1 (insulin-dependent) diabetic patients with normo- and microalbuminuria

Kidney biopsies from 15 type-1 (insulin-dependent) diabetic patients with a range of albumin excretion (AER) were analyzed. Nine patients had normal AER, and six had microalbuminuria. Basement membrane thickness, BMT, and mesangial matrix volume fraction, Vv(mat/glom), were obtained from at least three glomeruli per biopsy. Mesangial structures were estimated with electron microscopic analysis at three levels in each glomerulus. Glomerulopathy parameters were significantly increased in micro- versus normoalbuminuric patients with the following means and (CV): BMT 571 nm (0.12) and 442 nm (0.25), P = 0.03; Vv(mes/glom) 0.31 (0.20) and 0.22 (0.14), P = 0.002; Vv(matrix/glom) 0.17 (0.25) and 0.11 (0.28), P = 0.006; matrix star volume 56 microns 3 (0.47) and 22 microns 3 (0.43), P = 0.02. A positive correlation obtained between AER and each of the glomerulopathy parameters, BM thickness, Vv(mes/glom) and Vv(matrix/glom), as well as between AER and a structural index expressing the sum of changes in the peripheral BM and in the mesangium (r = 0.62, P = 0.01). The results indicated a parallel course of mesangial and peripheral BM changes: a positive correlation obtained between BM thickness and mesangial parameters [BMT versus Vv(matrix/glom): r = 0.82, P = 0.0001] and the ratio of the two subsets of glomerular BM material (PBM:matrix) did not show significant difference between normo- and microalbuminuric groups. The data give strong support to the contention that the transition from normo- into the microalbuminuric phase is linked to progressing glomerulopathy.

Prognostic significance of microalbuminuria in insulin-dependent diabetes mellitus: a twenty-three year follow-up study

A cohort of 63 Type 1 insulin-dependent diabetic patients were first characterized for overnight urinary albumin excretion rate (AER) in 1967. In 1981, seven out of eight (87%) patients with initial AER greater than or equal to 30 less than or equal to 140 micrograms/min (microalbuminuria) developed clinical proteinuria compared to only 2 out of 55 (4%) patients with initial AER less than 30 micrograms/min. The same cohort of patients was reassessed in 1990 after a total follow-up period of 23 years. The aim was to investigate the role of microalbuminuria in the prediction of total/cardiovascular mortality and the development of renal failure, in addition to clinical proteinuria. The initially microalbuminuric patients had a significantly higher risk of developing not only clinical proteinuria (relative risk 9.3, 95% C.I. 1.36 to 3.10, P less than 0.05), but also of dying from a cardiovascular cause (relative risk 2.94, 95% C.I. 1.18 to 7.34, P less than 0.05). The rate of progression to renal failure was higher but not significantly so in the microalbuminuric (2 of 8) compared to the normoalbuminuric (4 of 53) group (relative risk 3.31, 95% C.I. 0.72 to 15.24, NS). In insulin-dependent diabetic patients microalbuminuria is a powerful predictor of clinically overt diabetic renal disease as well as cardiovascular mortality.

Gestational diabetes. Can epidemiology help?

Diagnostic criteria for diabetes mellitus (DM) and impaired glucose tolerance from oral glucose tolerance test results in adults are reviewed in the epidemiological context, highlighting the residual differences between World Health Organization (WHO) and National Diabetes Data Group (NDDG) glycemic criteria with respect to the diagnosis of gestational diabetes. Although the value of the diagnosis of DM (WHO/NDDG criteria) in pregnancy is not called into question, attention is drawn to the paucity of evidence linking lesser degrees of glucose intolerance with significant disturbance of pregnancy outcome when confounding variables such as maternal age, adiposity, and parity are allowed for. It is in the area of the detection and treatment of these lesser degrees of glucose intolerance in pregnancy that serious questions of the detriment-to-benefit ratio arise. A population-based multiethnic multicultural inquiry into diagnostic methodology and criteria in pregnancy is proposed, jointly sponsored by the WHO and the International Diabetes Federation, extending, if possible, to a controlled clinical trial of the effects of intervention.