Lipid but not glycaemic parameters predict total mortality from type 2 diabetes mellitus in Canterbury, New Zealand

Lipid risk factors among elderly with normal fasting glucose, impaired fasting glucose and type 2 diabetes mellitus. The Italian longitudinal study on aging

BACKGROUND AND AIMS

Three groups of subjects were identified within a representative sample of older Italians: subjects with normal fasting glucose (NFG), with impaired fasting glucose (IFG) or with type 2 diabetes mellitus (T2D). The aim of the present study was to evaluate the relationship among plasma lipids, lipoproteins, other metabolic factors in the three groups, and their role in predicting total fatal events.

METHODS AND RESULTS

2422 subjects, aged 65-84 years, taking part into the Italian Longitudinal Study on Aging were included in the analyses. Factor analysis was conducted separately for men and women. Factor scores were used as independent variables in Cox Proportional Hazard models, to determine factors predicting death at the follow-up in NFG, IFG and T2D subjects. Four major factors were found for men ("insulin resistance", "body size", "total cholesterol", "HDL cholesterol") and four also for women ("insulin resistance", "total cholesterol", "body size", "HDL cholesterol"). For NFG and IFG men, and for both T2D men and women, the "HDL cholesterol" was a significant protective factor for total deaths (NFG men: HR = 0.79, 95% CI 0.67-0.93; IFG men: HR = 0.59, 95% CI 0.45-0.79; T2D men: HR = 0.55, 95% CI 0.34-0.89; T2D women: HR = 0.61, 95% CI 0.44-0.86). Among NFG women, the "body size" factor was also a protective factor with respect to total deaths (HR = 0.74, 95% CI 0.57-0.95).

CONCLUSION

A factor including HDL Cholesterol and Apo A-I showed protection against all-cause mortality in older men, independently from the glycemia level, and in women only in those diagnosed with T2D.

Short-term impact of HbA1c on morbidity and all-cause mortality in people with type 2 diabetes: a Danish population-based observational study

AIMS/HYPOTHESIS

In a population-based setting, we investigated whether diabetes-related morbidity and all-cause mortality within 2 years of HbA(1c) measurement were associated with that HbA(1c) level in individuals with type 2 diabetes. The main objective was to compare outcomes in those with HbA(1c) ≥ and <7% (53 mmol/mol).

METHODS

Individuals with type 2 diabetes from Aarhus County, Denmark, were identified from public data files in a 3 year period (2001-2003). Stratifying the 17,760 individuals by HbA(1c), we estimated HRs for diabetes-related morbidities and all-cause mortality using Cox regression. Results were also stratified by treatment modality.

RESULTS

In total, 1,805 individuals experienced at least one diabetes-related morbidity and 1,859 individuals died. In general, the HRs in adjusted analyses of diabetes-related morbidity and mortality were increased for HbA(1c) ≥ 7% (53 mmol/mol): morbidity, HR 1.48 (95% CI 1.34, 1.63); and mortality, HR 1.26 (95% CI 1.15, 1.39). On grouping individuals according to HbA(1c) <5% (31 mmol/mol), 5.0-5.9% (31-41 mmol/mol), 6.0-6.9% (42-52 mmol/mol), 7.0-7.9% (53-63 mmol/mol), 8.0-8.9% (64-74 mmol/mol) and ≥ 9% (75 mmol/mol), the HRs for mortality formed a U shape, with HbA(1c) 6.0-6.9% (42-52 mmol/mol) at the lowest point. For diabetes-related morbidity, a dose-response pattern appeared (lowest for HbA(1c) < 5% [31 mmol/mol]). Patterns of HR differed with treatment modality.

CONCLUSIONS/INTERPRETATION

An HbA(1c) level ≥ 7% (53 mmol/mol) was associated with increased morbidity and mortality. Both high and very low levels of HbA(1c) were associated with increased mortality. A dose-response pattern appeared for morbidity. The impact of HbA(1c) level on morbidity and mortality depended on treatment modality.

Guidelines improve general trend of lowered cholesterol levels in type 2 diabetes patients in spite of low adherence

BACKGROUND

New guidelines were introduced in Sweden in 1999 to reduce the risk of cardiovascular disease among diabetes patients. The impact of the new guidelines on lipid levels in a diabetes patient population has not been extensively studied. Our aim was to study whether the introduction of treatment goals for dyslipidaemia was reflected in lower cholesterol levels in patients with diabetes in a general population.

METHODS

In a population of 59,338 individuals, 971 (1.6%) had diabetes. All subjects were 40, 50 or 60 years of age and participated in the Vasterbotten Intervention Programme in 1995-2004. Cholesterol levels and use of lipid-lowering drugs were measured, and trends in cholesterol levels were analysed before and after the guidelines were introduced in 1999.

RESULTS

In this effectiveness study, there was a marked decrease in mean plasma total cholesterol levels among patients with diabetes (5.79 (+/- 1.21) mmol/1 in 1995-1999 and 5.07 (+/- 1.00) mmol/1 in 2000-2004 (p<0.001)) as well as in the non-diabetic population (5.79 (+/-1.15) mmol/1 and 5.41 (+/-1.07) mmol/1 (p<0.001)). The trend in diabetes patients was influenced by increased use of lipid-lowering agents, even though only 25.3% (male/female 26.8%/23.2%) of the diabetes patients received lipid-lowering treatment after the introduction of the new guidelines.

CONCLUSIONS

Since the introduction of the guidelines, an increasing number of diabetes patients are receiving lipid-lowering drugs, which enhance a strong general trend of lowered cholesterol levels. Yet, the vast majority of diabetes patients with hypercholesterolaemia still do not receive medical treatment in accordance with the guidelines.

Influence and interaction of diabetes and lipoprotein (a) serum levels on mortality of patients with peripheral artery disease

BACKGROUND

Diabetes mellitus is a risk factor for early complications and mortality in patients with peripheral artery disease. Lipoprotein (a) [Lp(a)] is also suggested to be a marker of increased cardiovascular risk. We investigated the association and interaction between diabetes mellitus, lipoprotein(a) and mortality in high risk patients with peripheral artery disease (PAD).

METHODS

We studied 700 consecutive patients [median age 73 years, interquartile range (IQR) 62-80, 393 male (56%)] with PAD from a registry database. Atherothrombotic risk factors (diabetes, smoking, hyperlipidaemia, arterial hypertension) and Lp(a) serum levels were recorded. We used stratified multivariate Cox proportional hazard analyses to assess the mortality risk at a given patient's age with respect to the presence of diabetes and Lp(a) serum levels (in tertiles).

RESULTS

Patients with Lp(a) levels above 36 mg dL(-1) (highest tertile) and insulin-dependent type II diabetes had a 3.01-fold increased adjusted risk for death (95% confidence interval 1.28-6.64, P = 0.011) compared to patients without diabetes or patients with non-insulin-dependent type II diabetes. In patients with Lp(a) serum levels below 36 mg dL(-1) (lower and middle tertile), diabetes mellitus was not associated with an increased risk for death.

CONCLUSION

Insulin-dependent type II diabetes mellitus seems to be associated with an increased risk for mortality in PAD patients with Lp(a) serum levels above 36 mg dL(-1). PAD patients with non-insulin-dependent type II diabetes, and patients with diabetes and Lp(a) levels below 36 mg dL(-1) showed survival rates comparable to PAD patients without diabetes.

Renal damage in patients with Type 2 diabetes: a strong predictor of mortality

AIMS

(i) To compare mortality rates in a cohort of Type 2 diabetic patients with those of the general population; (ii) to assess the prognostic role of pre-existing chronic conditions; (iii) to evaluate the impact of different severity of renal damage on mortality.

METHODS

All 3892 patients with Type 2 diabetes attending our Diabetic Clinic during 1995 and alive on 1 January 1996 were identified and followed for 4.5 years. Information on vital status (100% complete) and causes of death (98.5% complete) for 599 deceased subjects was derived from death certificates.

RESULTS

In comparison with the general population, standardized mortality ratios (x 100) were: 125 (95% confidence interval 104-148) in patients aged < 75 and 85 (75-95) in patients > or = 75 years. Cardiovascular diseases and diabetes were responsible for most of the excess deaths. In a Cox-proportional hazard model, renal damage was a powerful predictor of death (hazard ratio = 2.39; 95% confidence intervals = 2.00-2.85). The severity of renal damage was associated with increasing hazard ratios for death from all-cause mortality and from specific causes (especially coronary artery disease, other cardiovascular causes and diabetes) after multiple adjustments. Other significant predictors of death were: greater age, glycated haemoglobin, smoking, lower body mass index, pre-existing coronary and peripheral artery disease and known co-morbidity (cirrhosis and cancer).

CONCLUSIONS

Renal damage of any severity is significantly associated with subsequent mortality from all causes and from cardiovascular diseases. These associations are not confounded by pre-existing co-morbidity or coronary diseases.

Management of co-existing diabetes mellitus and dyslipidemia: defining the role of thiazolidinediones

The observed reduction in macrovascular outcomes in the United Kingdom Progressive Diabetes Study (UKPDS) trial in patients with type 2 diabetes mellitus (DM), treated intensively with insulin or sulfonylureas, was of borderline significance (p = 0.052). This may be because of the role of factors other than glycemic control in the etiology of macrovascular disease. The UKPDS and other studies have suggested that lipid parameters are potent predictors of adverse outcomes in patients with type 2 DM. In patients with DM, dyslipidemia is characterized by elevated serum triglycerides and low high density lipoprotein-cholesterol (HDL-C) with normal total serum cholesterol levels and usually accompanied by an elevation of atherogenic, small, dense low density lipoprotein-cholesterol (LDL-C) particles. Dyslipidemia is only partly corrected by dietary and lifestyle modifications and pharmacological glycemic control in patients with DM. Several guidelines, including those published by the New Zealand Heart Foundation, suggest that lipid-modifying therapies are appropriate in patients considered to be at high or very high risk of a cardiac event. This includes patients with established vascular disease. Some recent studies suggest that patients with type 2 DM have risk comparable to patients without DM, but have experienced previous myocardial infarction (MI). Subgroup analysis of trials including the Scandinavian Simvastatin Survival Study (4S) and Cholesterol and Recurrent Events (CARE), which included patients with DM, have shown a significant reduction in adverse outcomes, although many patients with DM and dyslipidemia were excluded. Of lipid-lowering drugs, fibric acid derivatives are probably the most appropriate for patients with DM and dyslipidemia and their role is being evaluated in large, long-term outcome studies such as Fenofibrate Intervention and Event Lowering in Diabetes (FIELD). Thiazolidinediones, a new class of compound for treating patients with type 2 DM, primarily exert their glucose-lowering effect by increasing insulin sensitivity at the level of skeletal muscle, and to a lesser extent, at the liver by decreasing hepatic glucose output. Some of their actions are mediated through binding and activation of the peroxisome proliferator-activated receptor-gamma, a nuclear receptor that has a regulatory role in differentiation of cells, especially adipocytes. The nonhypoglycemic effects of thiazolidinediones, therefore, offer additional potential mechanisms for benefit in patients with type 2 DM and insulin resistance. Thiazolidinediones increase serum HDL-C levels. Troglitazone and pioglitazone have been shown to decrease serum triglyceride levels. Rosiglitazone, conversely has no significant effect on serum triglyceride levels. All of the thiazolidinediones increase serum LDL-C levels (pioglitazone to a lesser extent), although changes in the size of the LDL fraction may render it less susceptible to oxidation and, therefore, less atherogenic. A randomized comparative trial needs to be undertaken to determine whether true differences exist between the thiazolidinediones. Longer studies need to be undertaken to assess their effect on cardiovascular outcomes.

Predictors of mortality from type 2 diabetes mellitus in Canterbury, New Zealand; a ten-year cohort study

The aim was to establish mortality rates in a cohort of subjects with type 2 diabetes mellitus over 10 years in Canterbury, New Zealand (NZ) and to determine baseline prognostic factors. Subjects (447) with type 2 diabetes (208 male, 239 female; age range 30-82 years, median 62 years; of predominantly European origin) were characterised in a clinic survey in 1989. Individual status (dead or alive) at June 1 1999 (10 year follow-up) was ascertained. Mortality rates were compared with the general NZ population and the relative risk (RR) of baseline prognostic factors evaluated with Cox's proportional hazards model. At 10 years, 232 subjects were confirmed as alive and 187 as dead - only 28 were untraceable. Ten year survival was 55% (95% CI: 50-60) for the cohort, compared with 70% (95% CI: 65-75) at 6 years. Factors assessed at baseline (1989), that were independently prognostic of total mortality, included age (RR 2.0, 95% CI: 1.6-2.5), pre-existing coronary artery disease (CAD; RR 1.7, 95% CI: 1.2-2.4) and albuminuria (RR 1.58, 95% CI: 1.1-2.3). Glycated haemoglobin was not a significant predictor of total mortality, although was a predictor of CAD mortality in those subjects free of CAD in 1989 (RR 1.6, 95% CI: 1.1-2.3). In the latter subset, independent prognostic factors for CAD mortality also included age (RR 2.5, 95% CI: 1.7-3.8), hypertension (RR 1.9, 95% CI: 1.0-3.7), peripheral vascular disease (RR 2.4, 95% CI: 1.3-4.5) and smoking (RR 2.6, 95% CI: 1.2-5.8). Increased mortality in type 2 diabetic subjects is therefore attributable to multiple risk factors. Improved outcomes will depend on interventions targeted at glycaemic and all other remediable factors.

High impact of nephropathy on five-year mortality rates among patients with Type 2 diabetes mellitus from a multi-ethnic population in New Zealand

AIMS

Type 2 diabetes mellitus and its complications are common among Polynesians in New Zealand. This study investigated the mortality from diabetes among indigenous Maori and recent migrants from the South Pacific.

METHODS

Death certificates and other reports were collected to enumerate those who had died in an across-community cohort study of 765 diabetic patients aged 40-79 years in 1991. Five year mortality status was ascertained in 99.7% and death certificates were obtained from 129 (88%) of the 146 who had died. Diabetes was missed from 36% of death certificates.

RESULTS

Compared to Europeans with Type 2 diabetes, Maori with Type 2 diabetes were 2.66 (1.63-4.35) fold as likely to die from diabetes-related conditions, including a 13.1 (3.7-46.4) fold greater risk of death from nephropathy. Pacific Islands Polynesians with Type 2 diabetes had a similar mortality to Europeans with Type 2 diabetes (hazards ratio 1.06 (0.68-1.65)). After 6 years, 10.7 (2.2-19.3)% more Maori had died than Pacific Islands Polynesians.

CONCLUSIONS

Maori with Type 2 diabetes are dying from diabetic complications, particularly nephropathy, at an alarming rate. The magnitude of the difference between Maori and Pacific Islands Polynesians suggests environmental rather than inherited factors are involved and these need further investigation.

Type 2 diabetes towards the new millennium--the relative importance of glycaemic versus lipid control

The prevalence of type 2 diabetes is set to increase. The UKPDS has shown that better average glycaemic control over time leads to a reduction in microvascular complications. Macrovascular outcomes are also reduced in overweight subjects treated with metformin. The UKPDS and our own data, however, show that the natural history of type 2 diabetes is one of progressive deterioration in glycaemic control despite treatment. Lipid parameters emerges as the strongest predictors of outcomes in type 2 diabetes and suggest where therapeutic endeavours might best be directed. Ongoing trials of lipid-modifying therapies in type 2 diabetes will help to substantiate this. In the meantime, efforts to improve glycaemic control should not be pursued to the exclusion of other abnormalities that may have a greater relevance to outcomes of type 2 diabetes. There is an urgent need for better prevention and intervention strategies as we approach the new millennium.

Causes of death and associated factors among patients with non-insulin-dependent diabetes mellitus in Taipei, Taiwan

A cohort of 766 patients with non-insulin-dependent diabetes mellitus (NIDDM) from a general teaching hospital in Taipei, Taiwan were followed prospectively to assess survival experience and associated risk factors. Data were abstracted from the medical records and additional information was obtained from patients or their closest relatives using a structured questionnaire. Date and cause of death were determined from death certificates. Standardized mortality ratios were calculated by the direct method. Chi2-Square test and Cox's proportional hazard analysis were used to control for potential confounders. During a median follow-up of 3.5 years (range 1 month to 4.6 years), 131 deaths occurred. Of these, 29.8% were due to cardiopulmonary disease (ICD 401-429), 13.0% due to cerebrovascular disease (ICD 430-438), 13.0% due to acute diabetes metabolic complications (250.1, 250.2), and 11.4% due to nephropathy (580-589). Adjusted for age, people with NIDDM had 2.2 (95% CI 1.6-2.9) times the risk of death than members of the general population, and cause-specific standardized mortality ratios were: CPD 4.6, nephropathy 8.8, cerebrovascular disease 1.9, and neoplasm 0.7. Age, fasting plasma glucose, hypertension, and proteinuria were positively and independently associated with all-cause mortality (P < 0.05 for each). Thus, NIDDM patients have higher mortality rates than the general population in Taiwan, and age, fasting plasma glucose, hypertension, and proteinuria are associated with this excess risk. Proper application of available interventions may control these factors with a consequent reduction in mortality. Particular attention is needed to prevent deaths from the acute metabolic complications of diabetes.

Natural history of cardiovascular and renal disease in patients with type 2 diabetes: effect of therapeutic interventions and risk modification

Several observational studies document a considerably increased risk of advanced renal disease, cardiovascular disease, and early mortality in persons with diabetes. Both epidemiologic and observational studies indicate that progression of cardiovascular disease and renal disease is associated not only with high blood glucose levels, but also with hypertension and dyslipidemia. In persons with type 1 diabetes, hypoglycemic and antihypertensive therapy are important in the prevention of cardiovascular and renal disease. In those with type 2 diabetes, hypoglycemic therapy can help to prevent microvascular disease in the retina and in the kidney, and recent studies show that antihypertensive treatment is important in preventing cardiovascular disease. Thus, a multifactorial intervention program is key to preventing complications of hyperglycemia and, equally important, elevated blood pressure and dyslipidemia.

Clinical and biochemical outcomes of type 2 diabetes mellitus in Canterbury, New Zealand: a 6-year cohort study

There is a paucity of data regarding outcomes of Type 2 diabetes mellitus. A cohort of 447 Type 2 diabetic subjects (208 male, 239 female; age range 30-82 years, median 62 years; and of predominantly European origin) was characterised in a clinic survey in 1989. Individual status (dead or alive) at 1 June 1995 was ascertained. At 6 years, 289 subjects were confirmed as alive and 133 as dead--only 25 were untraceable. Of those subjects identified as alive, follow-up clinical and biochemical data were obtained for 253 (87.5%) individuals. In those subjects, glycated haemoglobin deteriorated from 63.1 +/- 18.7 mmol/mol haem in 1989 to 71.7 +/- 24.4 in 1995, P < 0.0001. An increased prevalence of retinopathy was evident at 6-year follow-up, 59.7% cases in 1995 compared with 39.5% in 1989, P < 0.001. Similarly there was an increased prevalence of coronary artery disease (CAD) (33.6 vs 18.2% of cases), albuminuria (26.5 vs 19% of cases; P < 0.001), and hypertension (71.5 vs 54.9% of cases; P < 0.001) in 1995 vs 1989, respectively. Multiple logistic regression analysis showed that glycated haemoglobin (odds ratio (OR) for 18 mmol/mol haem change, 1.78; 95% CI, 1.15-2.85), hypertension (OR, 3.33; 95% CI, 1.40-8.41) and known duration of diabetes (OR for 7 year change, 2.12; 95% CI, 1.24-3.80) were predictors for development of retinopathy. There is therefore a deterioration in glycaemic control in Type 2 diabetes over 6 years and an increased prevalence of complications that present strategies in a multidisciplinary specialist diabetes clinic are unable to prevent on a sustainable basis.