Lipids, diabetes, and vascular disease: the time to act

Design of the Collaborative AtoRvastatin Diabetes Study (CARDS) in patients with type 2 diabetes

BACKGROUND

There are few data on the role of lipid lowering in the primary prevention of coronary heart disease (CHD) in diabetic patients. This paper describes the design of a collaborative clinical trial between Diabetes UK, the NHS Research and Development Directorate and Pfizer UK, that addresses this question.

METHODS

The Collaborative AtoRvastatin Diabetes Study (CARDS) is a multicentre, randomized, placebo-controlled, double-blind clinical trial of primary prevention of cardiovascular disease in patients with Type 2 diabetes. The primary objective is to investigate whether treatment with the hydroxymethylglutaryl coenzyme A reductase inhibitor, atorvastatin, reduces the incidence of major cardiovascular events. At entry patients have at least one other risk factor for CHD in addition to diabetes, namely current smoking, hypertension, retinopathy, or micro- or macroalbuminuria. At randomization patients have been selected for a serum low-density lipoprotein (LDL) cholesterol concentration < or = 4.14 mmol/l (160 mg/dl) and triglycerides < or = 6.78 mmol/l (600 mg/dl). Randomization was completed in June 2001. Patients will be followed until 304 primary endpoints have accrued (expected date early 2005). The trial includes 2838 men and women aged 40-75 years. This report describes the design and administration of the study and reviews the evidence to date of the effectiveness of lipid-lowering therapy in Type 2 diabetes.

CONCLUSIONS

The case for lipid-lowering therapy for the primary prevention of CHD in diabetes has not been demonstrated. CARDS will provide essential information on the extent of any benefits and adverse effects of lipid-lowering therapy in diabetic patients without prior CHD.

Atherosclerosis risk factors related to hemodialysis duration and erythropoietin therapy

Patients undergoing hemodialysis are at risk for atherosclerosis and its complications. The aim of this study was to examine the effect of erythropoietin therapy and hemodialysis duration on some of the atherosclerotis risk factors. The patients were divided into four groups: I: patients undergoing hemodialysis for less than 10 years (n=22); II: patients undergoing hemodialysis for more than 10 years (n=17); III: patients on no erythropoietin (n=21); IV: patients on erythropoeitin therapy (n=18). A control group of 20 subjects was also examined. Triglycerides, total cholesterol, low-density lipoprotein and high-density lipoprotein, lipoprotein(a), apolipoprotein-A1, apolipoprotein-B and lipid peroxidation were examined. There was a significant increase in triglycerides, to 2.59+/-1.2 mmol/l (p<0.001) and in lipid peroxidation in hemodialysis patients, to 5.02+/-0.9 micromol/l vs. controls (p<0.001). Significantly elevated triglycerides and lipid peroxidation levels were found in the patients with longer hemodialysis duration. Triglycerides were elevated in group II vs. group I, to 2.90+/-1.0 mmol/l. (p<0.05). Lipid peroxidation in group II, 5.40+/-1.0 micromol/l, showed significant difference compared to group I (p<0.05). Erythropoietin treatment did not affect any of the examined parameters. These results indicate increased risk for atherosclerosis related to hemodialysis duration. Besides the renal disease itself, hemodialysis may also be one of the risk factors for atherosclerosis.

Plasma lipids and urinary albumin excretion rate in Type 1 diabetes mellitus: the EURODIAB IDDM Complications Study

AIMS

To examine the relationship between increased urinary albumin excretion rate and fasting plasma lipids among male and female respondents to the EURODIAB IDDM Complications Study, and attempt to explain inconsistencies in previous reports.

METHODS

A cross-sectional study of 3250 randomly selected Type 1 diabetic patients from 31 diabetes clinics in 16 European countries was carried out between 1989 and 1990. Plasma lipids and urinary albumin were measured centrally. The present analysis was confined to the subgroup of 2205 patients attending after a 10-12 h overnight fast. Mean age was 33 years (SD 10) and mean duration of Type 1 diabetes mellitus was 15 years (SD 9).

RESULTS

The prevalence of microalbuminuria (24-h urinary albumin excretion rate 20-200 microg/min) was 21.7% (95% confidence interval 19.9-23.5) and macroalbuminuria (24-h urinary albumin excretion rate > 200 microg/min) 7.8% (6.6-9.0). In comparison to patients with normal urinary albumin excretion rate (< 20 microg/min), and after controlling for age, sex, glycaemic control, duration of diabetes and current smoking, macroalbuminuria was associated with significantly (P<0.01) increased fasting plasma triglycerides, cholesterol, LDL-cholesterol, cholesterol:HDL-cholesterol ratio and, in women, reduced HDL-cholesterol. In men and women with microalbuminuria, the only significant association was with increased plasma triglycerides.

CONCLUSIONS

These data confirm that there is an association between fasting plasma lipids and increasing urinary albumin excretion rate in European Type 1 diabetic patients. In microalbuminuric patients, however, the association was weaker than previously reported and partly explained by confounding factors.

An atherogenic midband lipoprotein: a risk factor for coronary artery disease in diabetes mellitus with hyperlipidemia

On polyacrylamide gel (PAG) disc electrophoresis of serum lipoproteins, the band(s) which migrates between pre beta- and beta-lipoproteins was more frequently observed in hyperlipidemics with diabetes mellitus (73%), than in those without diabetes mellitus (37%) (P < 0.01). Those bands were seen at three positions between pre beta- and beta-lipoproteins. A higher incidence of coronary artery disease (CAD) was observed in patients with midband as a shoulder of beta-lipoproteins (44%), than in those without midband (11%) (P < 0.05) after the matching of other risk factors. These results suggest that midband as a shoulder of beta-lipoproteins may be a risk factor for CAD in diabetes mellitus with hyperlipidemia.

Asymptomatic coronary artery disease in diabetes: relation to common risk factors, lipoproteins, apoproteins and apo E polymorphism

The risk factors for asymptomatic coronary artery disease (CAD) were examined in 138 diabetic patients. Following non-invasive screening examinations (exercise electrocardiography, dynamic thallium scintigraphy, 24-h electrocardiographic recording), CAD was confirmed angiographically in 21 symptom-free diabetic subjects with an ischaemic finding in at least one of the non-invasive tests. The prevalence of asymptomatic CAD in this cohort of diabetic patients was 21/132 (16%), which may be an underestimation because 6 patients refused angiography. Risk factors (age, diabetes, smoking, hypertension, serum lipoproteins, apoproteins and apo E phenotypes) were analysed according to the presence or absence of CAD. Multivariate logistic stepwise analysis did not show any definite changes of serum lipids, lipoproteins and apoproteins in type 1 (n = 72) and type 2 (n = 66) diabetic patients with or without asymptomatic CAD. The only factors associated with asymptomatic CAD were the duration of diabetes (P < 0.005) and the age of the patient (P < 0.05). These results suggest that in diabetic patients the major risk factor for premature coronary atherosclerosis is diabetes itself. Assessment of other risk factors does not seem to define any subgroup with asymptomatic CAD.

The effects of dietary sugar-beet fibre and guar gum on lipid metabolism in Wistar rats

This study investigates the mechanisms of action for the hypocholesterolaemic effects of sugar-beet fibre (SBF) and guar gum. Four groups of ten male Wistar rats were fed ad lib. on test diets containing either 100 g SBF or guar/kg, or control diets containing 100 g cellulose or wheat bran/kg for 28 d. Food intake, weight gain and food consumption ratios were unaffected by the diets. Circulating cholesterol and hepatic cholesterol concentrations were significantly lower in both SBF- and guar-fed groups compared with either cellulose- or bran-fed animals. Circulating triacylglycerol concentrations were significantly lower in SBF- and guar-fed animals, but total hepatic lipid concentrations and hepatic and adipose tissue lipogenesis rates were unaffected by the diets. Hepatic cholesterol-7 alpha-hydroxylase (EC 1.14.13.17) activities were significantly higher in the guar-fed animals compared with cellulose or bran control groups. Hepatic 3-hydroxy-3-methylglutaryl-CoA reductase (EC 1.1.1.88) activities were unaffected. Circulating bile acid concentrations were significantly lower in SBF- and guar-fed animals and faecal bile acid output was significantly higher in the guar-fed group compared with bran- or cellulose-fed groups. This study supports the hypothesis that guar exerts its hypocholesterolaemic effect via intraluminal bile acid binding and loss of cholesterol from increased faecal bile acid excretion. The mechanism of action for the hypocholesterolaemic effect of SBF is less clear; the results of the present study point to a mechanism involving disruption of the enterohepatic bile acid circulation, possibly via changes in the rate of absorption of dietary lipid.

Low-density lipoprotein particle size in type 2 diabetic patients and age matched controls

Non-enzymatic glycation of low-density lipoprotein (LDL), and the predominance of small dense LDL particles may together contribute to the increased risk of atherosclerosis in diabetes. We aimed to establish whether the size of LDL particles is related to plasma triglyceride concentration, and to the extent of LDL glycation in type 2 diabetic patients. Sixteen men with type 2 diabetes and 16 age matched non-diabetic controls were studied. LDL size was measured by rapid density gradient ultracentrifugation, and LDL glycation by affinity chromatography. Modal LDL density correlated with plasma triglyceride concentrations in both diabetic and control groups (r = 0.86, P < 0.0001, and r = 0.76, P < 0.0008, respectively). There was no significant difference in these variables between the groups. LDL modal density showed no correlation with HbA1, serum fructosamine or plasma glucose in either group. In the diabetic group the degree of LDL glycation correlated with serum fructosamine (r = 0.74, P < 0.001), HbA1 (r = 0.65, P < 0.008), and with plasma glucose (r = 0.64, P < 0.008). Our results suggest that, in well controlled type 2 diabetic patients LDL size is independent of short-term glycaemic control but can be predicted by plasma triglyceride concentrations.

Lipoprotein composition in the insulin-deficient non-acidotic phase of type I diabetic patients and early evolution after the start of insulin therapy

Lipoproteins, including intermediate density lipoproteins and lipoprotein(a), and apolipoproteins A-I, B, C-II, C-III and E, were studied in 13 newly-diagnosed type I diabetic patients with severe insulinopenia without dehydration or acidosis. At baseline, the main finding was a significant increase in serum triglycerides due to raised triglyceride concentrations in all lipoproteins, particularly triglyceride-rich lipoproteins. Cholesterol concentrations were slightly increased in lipoproteins and led to a significant increase in serum cholesterol. Two days after the start of insulin therapy, lipoprotein profiles had normalized except for the LDL triglyceride contents, which remained significantly increased on the fifth day of treatment. No significant modifications were observed in lipoprotein(a), apolipoproteins A-I and E concentrations throughout the study. However, serum apolipoproteins B, C-II and C-III were increased at baseline and fell to normal levels 2 days after the start of insulin therapy. On the other hand, apolipoprotein C-II/C-III ratios in high and very low density lipoprotein, showed no significant differences at baseline compared with controls, suggesting that an apolipoprotein C-II deficiency or apolipoproteins Cs imbalance can be ruled out. In conclusion, significant lipoprotein abnormalities were observed in the insulin-deficient state of type I diabetes mellitus; insulin therapy normalizes the lipoprotein profile in two days, except for low density lipoprotein triglyceride contents which remain increased at the fifth day.

Lipoprotein(a) levels in relation to diabetic complications in patients with non-insulin-dependent diabetes

The relationship between serum levels of lipoprotein(a) Lp(a)) and the presence of chronic diabetic complications was studied in 194 patients with non-insulin-dependent diabetes mellitus (NIDDM; 75 males, 119 females; age 66 +/- 11 years; duration of diabetes, 11 (range 1-35) years). They were taking various treatments (diet alone, oral hypoglycaemic agents and/or insulin). Metabolic status and prevalence of diabetic complications were assessed by detailed history, physical examination, laboratory analysis and ECG. Average metabolic control was moderate (HbA1c 8.2 +/- 1.7%). Median serum Lp(a) level was 183 U l-1 (range 8-2600 U l-1), which was significantly higher than in control subjects of comparable age (median 101; range 8-1747 U l-1; P < 0.05), while HDL-cholesterol levels were lower (1.14 +/- 0.38 vs. 1.35 +/- 0.35 mmol l-1; P = 0.001), and total cholesterol levels were comparable. No significant relationships between diabetes treatment or metabolic control and Lp(a) levels were observed. In the quartile of patients with the highest Lp(a) levels, total cholesterol and triglycerides were slightly higher (P < 0.05), whereas HDL-cholesterol was not different. With increasing Lp(a) levels, higher prevalences of preproliferative retinopathy and of coronary artery disease (CAD) were observed, but not of the other complications. No relationship was found between the degree of albuminuria and Lp(a) levels. We conclude that in NIDDM patients, Lp(a) levels are elevated compared with non-diabetic subjects, and that higher Lp(a) levels are associated with higher prevalences of CAD and of retinopathy.

The effect of non-starch polysaccharide supplementation on circulating bile acids, hormone and metabolite levels following a fat meal in human subjects

The effects of guar gum, sugar-beet fibre (SBF) and wheat bran supplementation of a high-fat test meal were compared with an NSP-free control meal and a meal containing an equivalent amount of the ion-exchange resin cholestyramine in healthy non-obese human volunteers. Their effects on gastric emptying, postprandial circulating bile acids, triacylglycerols and gastrointestinal hormone levels were studied. The in vitro binding of NSP and cholestyramine to [1-14C]glycocholic acid was measured and compared with their in vivo effect. Guar gum and cholestyramine supplementation significantly lowered circulating postprandial bile acid, triacylglycerol and gastric inhibitory polypeptide concentrations, but sugar-beet fibre and wheat bran were without effect. Liquid gastric emptying, as assessed by circulating paracetamol levels, was slightly accelerated in the guar gum-supplemented meal. Glycocholic acid bound strongly to the insoluble fraction of cholestyramine and the soluble fraction of guar gum. The insoluble fractions of SBF and wheat bran bound only small quantities of glycocholate; no bile acid binding was detected in the soluble fractions of these NSP. The study demonstrates that measurement of postprandial bile acids enables an indirect measurement to be made of bile acid binding to NSP in vivo. The results support the hypothesis that the hypocholesterolaemic action of guar gum is largely mediated via interruption of the enterohepatic bile acid circulation, but indicate that the hypocholesterolaemic action of SBF is mediated by another mechanism.

Altered regulation of cholesterol metabolism in type I diabetic women during the menstrual cycle

This study examines the relationship of cellular cholesterol metabolism to oestrogen and progesterone during the menstrual cycle in diabetic and non-diabetic subjects. Nine premenopausal diabetic women were compared to nine non-diabetic women of the same age. Oestrogen, progesterone, lipoproteins, including lipoprotein (a) (Lp(a)) and cholesteryl ester transfer protein (CETP) were determined in serum. Cellular cholesterol content and cellular cholesterol synthesis were measured in mononuclear leucocytes. There was no significant change in serum lipoproteins including Lp(a) during the cycle in either group. CETP activity was significantly higher over the 4 weeks in the diabetic patients compared with non-diabetic subjects (mean 463 +/- 30 mumol l-1 h-1 vs 405 +/- 28 mumol l-1 h-1, p < 0.01). Serum high density lipoprotein (HDL) cholesterol was significantly lower during the 4 weeks in the diabetic patients (1.7 +/- 0.1 mmol l-1 vs 1.8 +/- 0.1 mmol-1, p < 0.05). Cellular cholesterol synthesis decreased steadily up to the third week in cells from the control subjects whereas there was no significant change in cells from diabetic patients whose cellular cholesterol synthesis was higher at week 3 compared with non-diabetic subjects (663 +/- 54 nmol mg-1 cell protein vs 432 +/- 43 nmol mg-1 cell protein, two-way interaction p < 0.05). There was a significant negative correlation between cellular cholesterol synthesis and serum oestrogen in the non-diabetic subjects (p < 0.05) but not in the diabetic patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Glycosylated low density lipoprotein is more sensitive to oxidation: implications for the diabetic patient?

Oxidised low density lipoprotein (LDL) is considered to be atherogenic. This study examined the relationship between glycosylation and oxidation of LDL from 10 normocholesterolaemic Type 2 diabetic patients, 10 hypercholesterolaemic Type 2 diabetic patients, and 10 normocholesterolaemic non-diabetic subjects. LDL was isolated by sequential ultracentrifugation and susceptibility to oxidation assessed by measuring thiobarbituric reactive substances (TBARS) during a 4-h oxidation period. LDL glycosylation was measured by aminophenylborate gel chromatography. Results demonstrated an increased susceptibility to oxidation in LDL from both diabetic groups, the mean 3-h TBARS values being 35.2 +/- 2.1 and 36.4 +/- 2.6 nmol MDA/mg LDL protein for normocholesterolaemic and hypercholesterolaemic diabetic patients compared with 24.5 +/- 2.5 nmol MDA/mg LDL protein for control subjects. LDL glycosylation of 2.20% +/- 0.11% and 2.89% +/- 0.46% for normocholesterolaemic and hypercholesterolaemic diabetic LDL was significantly higher than that for the non-diabetic control subjects of 1.60% +/- 0.12% (P < 0.02). There was a significant positive correlation (P < 0.005) between LDL glycosylation and LDL oxidation. The esterified/free cholesterol ratio which correlated positively with oxidation (P < 0.01) was significantly higher in LDL from both diabetic groups compared with LDL from control subjects (P < 0.01). Thus the increased incidence of atherosclerosis in diabetes may be related to glycosylation of LDL through its increased susceptibility to oxidation.

The regulation of post-prandial cellular cholesterol metabolism in type 2 diabetic and non-diabetic subjects

The purpose of the study was to determine the effect of diabetes on the regulation of postprandial cholesterol metabolism. Four groups of patients (n = 8 for each group) were examined: Type 2 diabetic patients with and without hypercholesterolaemia and non-diabetic subjects with and without hypercholesterolaemia. Serum lipoproteins, lipoprotein composition, cellular cholesterol, and cellular cholesterol synthesis were measured before and 4 h after a high calorie meal. The BMI for the hypercholesterolaemic diabetic patients of 31.5 +/- 0.95 (SEM) was significantly higher than that for the control group of 26.2 +/- 1.0 (p < 0.01). Fasting triglyceride levels were significantly higher in the normocholesterolaemic and hypercholesterolaemic diabetic patients and in the hypercholesterolaemic non-diabetic subjects (1.45 +/- 0.22, 2.27 +/- 0.34, and 1.58 +/- 0.18 mmol l-1, respectively) compared with normocholesterolaemic non-diabetic subjects (0.75 +/- 0.12 mmol l-1: p < 0.01). The normocholesterolaemic and hypercholesterolaemic diabetic subjects had significantly lower fasting serum high density lipoprotein (HDL) (1.06 +/- 0.08 and 1.04 +/- 0.06 mmol l-1) compared to the corresponding non-diabetic groups (1.29 +/- 0.11 and 1.45 +/- 0.17 mmol l-1, p < 0.05). The esterified/free cholesterol ratio of very low density lipoprotein (including chylomicrons VLDL-C) decreased postprandially in all groups with an overall decrease of 1.33 to 0.83 (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Apolipoprotein(a) and cardiovascular disease in type 2 (non-insulin-dependent) diabetic patients with and without diabetic nephropathy

The relative mortality from cardiovascular disease is on average increased five-fold in Type 2 (non-insulin-dependent) diabetic patients with diabetic nephropathy compared to non-diabetic subjects. We assessed the possible contribution of dyslipidaemia in general and elevated serum apolipoprotein(a) (apo(a)) in particular. Type 2 diabetic patients with normo-, micro- and macroalbuminuria were compared with healthy subjects. Each group consisted of 37 subjects matched for age, sex and diabetes duration. Serum creatinine in the nephropathy group was 105 (54-740) mumol/l. The prevalence of ischaemic heart disease (resting ECG, Minnesota, Rating Scale) was 57, 35, 19 and 2% in macro-, micro- and normoalbuminuric diabetic patients and healthy subjects, respectively. The prevalence of ischaemic heart disease was higher in all diabetic groups as compared to healthy subjects (p < 0.05), and higher in macroalbuminuric as compared to normoalbuminuric diabetic patients (p < 0.01). There was no significant difference between apo(a) in the four groups: 161 (10-1370), 191 (10-2080), 147 (10-942), 102 (10-1440) U/l (median (range)) in macro-, micro- and normoalbuminuric groups and healthy subjects. Serum total-cholesterol, HDL-cholesterol and LDL-cholesterol were not significantly different when comparing healthy subjects and each diabetic group. Apolipoprotein A-I was lower (p < 0.05) in all diabetic groups as compared to healthy subjects (nephropathy vs healthy subjects): 1.50 +/- 0.25 vs 1.69 +/- 0.32 g/l (mean +/- SD). Triglyceride was higher (p < 0.05) in patients with nephropathy and microalbuminuria as compared to healthy subjects (nephropathy vs healthy subjects): 2.01 (0.66-14.7) vs 1.09 (0.41-2.75) mmol/l (median (range)).(ABSTRACT TRUNCATED AT 250 WORDS)

Management of hyperlipidaemia: guidelines of the British Hyperlipidaemia Association

There is considerable evidence to suggest that the identification and treatment of dyslipidaemia will reduce the risk of premature CHD, i.e. before the age of 65. Diagnosis of the cause of raised plasma lipid levels will enable appropriate decisions to be taken with regard to management. The cornerstone of treatment is nutritional counselling and attention to other major risk factors for CHD, particularly smoking and hypertension. For a small percentage of patients with severe hyperlipidaemia drug therapy is indicated. Appropriate drug choices need to be made based on the particular lipid abnormality to be treated. In general those patients with clinical vascular disease are treated more aggressively than those where the aim is primary prevention. More research is needed to determine individual risk more precisely and to allow proper targeting of therapy. Genetic factors, qualitative changes in lipoproteins, lipoprotein (a), fibrinogen, and other coagulation and thrombotic factors are likely to be important in individual risk assessment. There is no doubt that more information is needed from prospective studies of lipid-lowering therapy in terms of risk benefit for affected individuals. Hopefully the major studies currently underway will fill some of the gaps in our knowledge. Until then aggressive therapy with drugs should be reserved for those at highest risk where the benefit is likely to be greatest.

Possible relevance of lipid peroxidation and thromboxane production to the initiation and/or evolution of microangiopathy in non-hyperlipidemic type 2 diabetes mellitus

To investigate the possible relevance of free radicals and prostanoids to the mode of initiation and/or evolution of microangiopathy in diabetes mellitus, we measured serum lipid peroxides (LPO), an accepted index of intravascular free radicals, and plasma 11-dehydrothromboxane B2 (11-dehydro-TXB2), a stable metabolite of vasoactive thromboxane A2 released from platelets, in 95 patients with normolipidemic type 2 (non-insulin-dependent) diabetes mellitus at different stages of the disease. In general, either LPO or 11-dehydro-TXB2 was significantly greater in the patients, as a group, than in the matched controls (3.82 vs. 2.65 nmol/ml, P < 0.01 for LPO; and 17.3 vs. 5.8 pg/ml, P < 0.01 for 11-dehydro-TXB2). In patients, both LPO and 11-dehydro-TXB2 increased according to the severity of their diabetic retinopathy. A highly significant positive correlation existed between the LPO values and 11-dehydro-TXB2 in the patients (r = 0.64, P < 0.0001), while there was no such relationship in the controls (r = 0.18, P = NS). No difference in serum levels of apolipoproteins A-I, A-II, B, C-II, C-III, or E was observed between the patients and controls. Short-term glycemic control (25 cal/kg of standardized body weight/day, for 8 weeks) resulted in a small but significant reduction in LPO (4.2 vs. 4.6 nmol/ml, control; P < 0.05) without alteration in 11-dehydro-TXB2. There was a tendency towards deterioration in LPO according to the improvement in glycemic control. These results appear consistent with the view that, in addition to LPO, the release of TXA2 from activated platelet in the human circulation could be an important factor for the initiation and/or evolution of microangiopathy in diabetic patients even when they are not apparently hyperlipidemic. Further, the results of the present study emphasize the notion that more tight control of serum lipids is worthy of serious consideration in preventing the advance of diabetic microangiopathy.

Apolipoprotein(a) in insulin-dependent diabetic patients with and without diabetic nephropathy

Insulin-dependent diabetic patients with diabetic nephropathy have a highly increased morbidity and mortality from cardiovascular diseases. To determine whether altered levels of apolipoprotein(a) (apo(a)), the glycoprotein of the potentially atherogenic lipoprotein(a) (Lp(a)), contribute to the increased risk of ischaemic heart disease, apo(a) was determined in 50 insulin-dependent diabetic patients with diabetic nephropathy (group 1), in 50 insulin-dependent diabetic patients with microalbuminuria (group 2), in 50 insulin-dependent diabetic patients with normoalbuminuria (group 3), and in 50 healthy subjects (group 4). The groups were matched with regard to sex, age and body mass index. The diabetic groups were also matched with regard to diabetes duration. The level of apo(a) was approximately the same in the four groups, being: 122 (x/ divided by 4.2) U l-1, 63 (x/ divided by 4.4) U l-1, 128 (x/ divided by 3.5) U l-1 and 126 (x/ divided by 3.7) U l-1 (geometric mean (x/ divided by antilog SD)) in group 1, 2, 3 and 4, respectively. 1 U l-1 apo(a) approximates 0.7 mg l-1 Lp(a).(ABSTRACT TRUNCATED AT 250 WORDS)

A longitudinal study on glucose tolerance and other cardiovascular risk factors: associations within an elderly population

From 1971 until 1975, 204 patients from a general practice, aged 64-87 at entry, were examined annually. At every examination body weight, serum lipids, and systolic blood pressure were measured, and a complete glucose tolerance test was carried out. Clinically diagnosed diabetics were excluded. Adjusted for age and sex, the annual change in the area under the glucose curve (AUC) was significantly associated with body weight change. Changes in serum total cholesterol, serum triglycerides, and systolic blood pressure were also associated with body weight change. The results were independent of potential confounders such as alcohol use, smoking habits, presence of cardiovascular disease, and baseline levels of the different risk factors. The change in AUC was also associated with changes in serum total cholesterol, independent of confounders such as body weight. Changes in AUC were not related to changes in systolic blood pressure and serum triglycerides. The results of this study suggest that changes in glucose tolerance are not only related to changes in body weight, but also to changes in serum cholesterol.

Doxazosin in the management of hypertensive diabetes--a cautionary note (?)

Twenty-two patients with diabetes and hypertension were treated with Doxazosin. An acceptable fall in blood pressure was found with 1 mg. in 50% of patients and 2-8 mgs. in 50%. An increase in HDL cholesterol and a fall in LDL cholesterol levels which reached statistical significance was observed. A small but significant increase in HBA1 levels occurred in the 50% of patients on the higher Doxazosin dose.

Decreased postheparin lipolytic activity in renal transplant recipients with cyclosporin A

The patterns of hyperlipidemia in renal transplant recipients (RTRs) are more variable than in the uremic state, showing increases in both very low-density lipoprotein (VLDL) and low density lipoprotein (LDL). This has been attributed, at least in part, to immunosuppressive therapy, especially to treatment with corticosteroids. Postheparin lipolytic activity (PHLA) was determined in 28 RTRs. Sixteen patients presenting with hyperlipidemia comprised group A, who were aged 49.8 +/- 13.5 years, and had a cholesterol of 8.24 +/- 1.86 mmol/liter, triglycerides of 6.02 +/- 3.33 mmol/liter. Twelve patients presenting cholesterol and triglyceride values within the normal range were in group B, and were aged 48.6 +/- 13.3 years. All RTRs received cyclosporin A (CsA) twice daily orally, which were divided in two equal doses and adjusted to provide CsA blood trough levels (RIA) in a range of 250 to 350 ng/ml. Twenty-one RTRs were additionally treated by alternate-day corticosteroids, whereas seven patients had CsA on their sole immunosuppressive agent. PHLA (mumol free fatty acids/ml/hr, given 10 and 20 min after 100 U/heparin kg body wt intravenously) was commonly reduced in RTRs (group A at 10/20 min: 5.6 +/- 1.1/5.26 +/- 1.2; group B: 8.26 +/- 2.91/8.38 +/- 3.44) as compared to the values obtained in healthy controls (15.3 +/- 2.9/17.2 +/- 5.0). This was mainly due to a reduction of the activity of the hepatic triglyceride lipase, and to a minor extent to a reduced activity of peripheral lipoprotein lipase. There was no statistically significant difference of PHLA in RTRs with or without corticosteroid treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Prospective comparative study in NIDDM patients of metformin and glibenclamide with special reference to lipid profiles

Twenty-two NIDDM patients completed an open randomized cross-over study comparing metformin and glibenclamide over 1 year. The drugs had an equivalent effect on glycaemic control, but, in contrast to glibenclamide, metformin reduced body weight. Neither drug affected triglycerides, total- and LDL-cholesterol or C-peptide. Metformin caused a slight elevation of HDL-cholesterol (P less than 0.05). No serious adverse effects were observed. The results show that oral hypoglycaemic agents are not associated with undesirable effects on lipids and lipoproteins.

Metabolic risk factors for cardiovascular disease in pancreas and kidney transplant recipients

Hyperinsulinaemia when combined with insulin resistance and hypertriglyceridaemia is a risk factor for cardiovascular disease. We have studied the serum lipid profile and glycaemic control in 27 uraemic diabetic patients, 23 Type 1 (insulin-dependent) diabetic kidney recipients, 18 non-diabetic kidney recipients, and 30 recipients of kidney and pancreas transplants at 6 months post-transplantation. Fasting serum triglycerides were increased in the uraemic diabetic patients and nondiabetic kidney transplanted patients but not in diabetic kidney transplanted patients whether or not they had received a pancreas. Total cholesterol was increased only in the uraemic diabetic patients while HDL cholesterol was normal in all groups. Within the pancreas and kidney transplanted group triglyceride values correlated with glomerular filtration rate (r = -0.55) but not with plasma insulin, glycated haemoglobin or kG-value following an intravenous glucose load. Plasma insulin was increased. Whether such isolated hyperinsulinaemia confers an increased risk of cardiovascular disease is not known. There may be adaptive feed-back mechanisms to protect target cells. Increasing the surgical risk in attempts to secure insulin delivery to the portal circulation does not seem warranted.

Screening for hyperlipidaemia in diabetes mellitus. Relationship to glycaemic control

Diabetic patients have an increased risk of developing cardiovascular disease which, in part, may be due to lipid abnormalities. Our aim was to establish from an initial screening programme what proportion of diabetic patients attending a routine diabetic outpatient clinic had hyperlipidaemia despite having good or acceptable glycaemic control. We screened 299 randomly selected diabetic patients to assess the prevalence of hyperlipidaemia and its relationship to glycaemic control. Twenty-eight per cent had hyperlipidaemia (defined as cholesterol greater than 6.5 mmol/L and/or non-fasting triglycerides greater than 3 mmol/L). Of these hyperlipidaemic patients, 71% had good or acceptable glycaemic control as defined by a glycated haemoglobin value of less than 10%. Approximately 40% of type 2 diabetic patients had body mass index values outside recommended targets indicating the potential of weight reduction in this group as a treatment modality. Our results indicate that the majority of hyperlipidaemic diabetic patients had good or acceptable glycaemic control, and as such these patients are potential candidates for specific lipid lowering therapy.

Management of newly diagnosed non-insulin-dependent (type 2) diabetes mellitus: a retrospective audit

A retrospective survey of the case records of 130 patients with newly diagnosed non-insulin-dependent diabetes mellitus (NIDDM) was performed to assess the effect of 1 year of clinical attendance on blood glucose control, body weight, lipid profile and blood pressure. The mean age of these patients was 63 +/- (SE) 0.1 years and 45% were 65 years or older. Body mass index (BMI) was 28.3 +/- 0.49 kg m-2 and 72% were overweight or obese. Sixty-seven percent of the patients were hypertensive (WHO criteria). Serum cholesterol was 6.0 +/- 0.2 mmol/l, HDL cholesterol 1.0 +/- 0.0 mmol/l and triglycerides 3.14 +/- 0.29 mmol/l (non-fasting). Seventy-two percent of the patients were managed on diet alone and 23% by diet plus sulphonylurea. The remaining 5% were treated by metformin or a combination of metformin plus sulphonylurea. After one year, glycated haemoglobin (HbA1) decreased from 10.7 +/- 0.3% to 8.2 +/- 0.2% (P less than 0.01; normal less than 7.5%). The sulphonylurea groups showed similar decreases in HbA1. Overall there was a small but significant fall in BMI (-0.5 +/- 0.2 kg m-2; P less than 0.05). However, the diet treated patients showed a significant decrease in BMI (-0.8 +/- 0.3 kg m-2; P less than 0.01) whilst BMI increased in the sulphonylurea treated group (+0.7 +/- 0.2 kg m-2; P less than 0.01). Serum lipid concentrations remained unchanged in both groups. The proportion of patients with hypertension remained the same. Hence after one year of clinical attendance, HbA1 improved but there was minimal change in the associated cardiovascular risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)

The distribution profiles of very low density and low density lipoproteins in poorly-controlled male, type 2 (non-insulin-dependent) diabetic patients

The distribution and composition of lipoproteins spanning the very low density and low density lipoprotein spectra have been analysed in ten poorly-controlled, male, Type 2 (non-insulin-dependent), diabetic patients pre-disposed to mild, secondary hypertriglyceridaemia. As compared to age-matched control subjects, the diabetic patients displayed grossly modified, distinctly atherogenic lipoprotein profiles. Modifications were not limited to the very low density lipoprotein profile, as would be expected from the pre-treatment hypertriglyceridaemia. There was also an aberrant low density lipoprotein profile, which was not evident from plasma cholesterol measurements, especially as the diabetic patients at entry were well matched to control subjects with respect to plasma levels of this lipid. Compositional abnormalities were also observed in the poorly-controlled diabetic group, although these were less marked than the distributional changes. There were substantial improvements of the abnormalities detailed above, even over a short treatment period (two weeks), with therapy designed primarily to ameliorate metabolic control. The data suggest that, in the presence of poor metabolic control and hypertriglyceridaemia, occult, atherogenic modifications of low density lipoproteins can occur. The results argue in favour of strict control of triglyceride levels even in diabetic patients with apparently acceptable cholesterol levels.

Kidney function and cardiovascular risk factors in non-insulin-dependent diabetics (NIDDM) with microalbuminuria

Microalbuminuria in non-insulin-dependent diabetes (NIDDM) is a strong predictor of increased mortality. The major causes of death are cardiovascular, whereas end-stage renal failure is of low frequency. To define kidney function and the presence of some assumed cardiovascular risk factors, we compared a group of 19 microalbuminuric NIDDM patients (M), of mean age (+/- SD) 65 +/- 4 years, and known duration of diabetes 8 +/- 7 years, with 19 randomly selected matched normoalbuminuric patients (N). Seven microalbuminuric patients (P) were also studied. Glomerular filtration rate (GFR) did not differ between N and M, whereas kidney volume was increased in M (260.3 +/- 54.1 ml 1.73 m-2) compared to N (220.4 +/- 44.8 ml 1.73 m-2; P = 0.018). The frequency of cardiac disease increased with increasing albuminuria. Glycaemic control did not differ between the groups, but fasting plasma C-peptide levels increased from 2.8 +/- 1.1 micrograms l-1 in N, to 3.7 +/- 1.7 micrograms l-1 in M (P = 0.08), and to 4.2 +/- 1.9 micrograms l-1 (P = 0.03) in P. The lipoprotein profile showed no significant differences, although the LDLcholesterol/HDLcholesterol (LDL-C/HDL-C) ratio tended to rise. A significant correlation was found between C-peptide and LDL-C/HDL-C (r = 0.5; P less than 10(-3]. In conclusion, GFR was not increased, and did not differ between N and M, whereas kidney volume was enhanced in M. Several assumed cardiovascular risk factors showed values of M intermediate between those of N and P.

Within-clinic reagent strip lipid measurement

The agreement between the Reflotron dry chemistry analyser and laboratory methods for measurement of total cholesterol and triglycerides was assessed by studying the between-method variability for individual samples. A paired comparison of replicate measurements from venous blood was made for 105 cholesterol and 90 triglyceride specimens. There was no significant mean difference between the two methods for cholesterol measurement (difference 0.02 mmol l-1, 95% Cl -0.07 to 0.10 mmol l-1) but there were wide limits of agreement (+/- 2SD) of -0.87 to 0.90 mmol l-1. Some of the differences in measurement were large enough to be clinically misleading and would result in inconsistencies in diagnostic assignment between the two methods. Both methods achieved relatively poor repeatability which limited the agreement possible (coefficient of repeatability, defined as 2SD of the differences, 0.59 mmol l-1 for the Reflotron and 0.38 mmol l-1 for the laboratory). The repeatability of triglyceride measurement was similar for the Reflotron and laboratory (coefficient of repeatability 0.24 mmol l-1 and 0.27 mmol l-1, respectively). However, there was a significant systematic difference between methods, with the Reflotron reading 0.30 mmol l-1 less than the laboratory method (95% Cl 0.26 to 0.35 mmol l-1) and the limits of agreement between the methods were -0.09 to 0.70 mmol l-1. It is important that clinicians recognize the limits of agreement between dry chemistry analysers and laboratory methods and take these into account when using them to screen for hyperlipidaemia or to monitor treatment of hyperlipidaemic diabetic patients.