The presence and severity of chronic kidney disease predicts all-cause mortality in type 1 diabetes

OBJECTIVES

This study aimed to identify clinical features associated with premature mortality in a large contemporary cohort of adults with type 1 diabetes.

RESEARCH DESIGN AND METHODS

The Finnish Diabetic Nephropathy (FinnDiane) study is a national multicenter prospective follow-up study of 4,201 adults with type 1 diabetes from 21 university and central hospitals, 33 district hospitals, and 26 primary health care centers across Finland.

RESULTS

During a median 7 years of follow-up, there were 291 deaths (7%), 3.6-fold (95% CI 3.2-4.0) more than that observed in the age- and sex-matched general population. Excess mortality was only observed in individuals with chronic kidney disease. Individuals with normoalbuminuria showed no excess mortality beyond the general population (standardized mortality ratio [SMR] 0.8, 95% CI 0.5-1.1), independent of the duration of diabetes. The presence of microalbuminuria, macroalbuminuria, and end-stage kidney disease was associated with 2.8, 9.2, and 18.3 times higher SMR, respectively. The increase in mortality across each stage of albuminuria was equivalent to the risk conferred by preexisting macrovascular disease. In addition, the glomerular filtration rate was independently associated with mortality, such that individuals with impaired kidney function, as well as those demonstrating hyperfiltration, had an increased risk of death.

CONCLUSIONS

An independent graded association was observed between the presence and severity of kidney disease and mortality in a large contemporary cohort of individuals with type 1 diabetes. These findings highlight the clinical and public health importance of chronic kidney disease and its prevention in the management of type 1 diabetes.

Metabolic syndrome as a risk factor for cardiovascular disease, mortality, and progression of diabetic nephropathy in type 1 diabetes

OBJECTIVE

To assess the predictive value of the metabolic syndrome in patients with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Patients were from the prospective Finnish Diabetic Nephropathy (FinnDiane) Study (n = 3,783): mean age 37 +/- 12 years and diabetes duration 23 +/- 12 years. Metabolic syndrome was defined according to World Health Organization (WHO), National Cholesterol Education Program (NCEP), and International Diabetes Federation (IDF) definitions. Follow-up time was median 5.5 years (interquartile range 3.7-6.7). Mortality data were complete, whereas morbidity data were available in 69% of the patients.

RESULTS

The WHO definition was associated with a 2.1-fold increased risk of cardiovascular events and a 2.5-fold increased risk of cardiovascular- and diabetes-related mortality, after adjustment for traditional risk factors and diabetic nephropathy. The NCEP definition did not predict outcomes when adjusted for nephropathy but markedly added to the risk associated with elevated albuminuria alone (P < 0.001). The IDF definition did not predict outcomes.

CONCLUSIONS

The metabolic syndrome is a risk factor, beyond albuminuria, for cardiovascular morbidity and diabetes-related mortality in type 1 diabetes.

Effect of parental type 2 diabetes on offspring with type 1 diabetes

OBJECTIVE

The purpose of this study was to study the association between a parental history of type 2 diabetes and the metabolic profile as well as the presence of the metabolic syndrome and diabetes complications in patients with type 1 diabetes.

RESEARCH DESIGN AND METHODS

This was a cross-sectional study design in 1,860 patients with type 1 diabetes from the Finnish Diabetic Nephropathy (FinnDiane) Study (620 patients with and 1,240 age-matched patients without a parental history of type 2 diabetes). Information on parental history was received from the type 1 diabetic offspring by a standardized questionnaire.

RESULTS

Patients with type 1 diabetes and a positive parental history of type 2 diabetes had a higher prevalence of the metabolic syndrome (44 vs. 38%; P = 0.013) and a metabolic profile related to insulin resistance (higher BMI, larger waist circumference, and higher triglycerides, A1C, and insulin dose per kilogram) and also had a later onset of type 1 diabetes (17.2 +/- 9.2 vs. 16.1 +/- 8.9 years; P = 0.008), which was also confirmed in the publicly available Diabetes Control and Complications Trial data set. In contrast, no association was observed with blood pressure, diabetes complications, or HLA genotype distribution. Parental history of type 2 diabetes was independently associated with age at onset of type 1 diabetes (odds ratio 1.02 [95% CI 1.01-1.03]), BMI (1.07 [1.02-1.12]), triglycerides (1.18 [1.03-1.35]), and insulin dose per kilogram (1.63 [1.04-2.54]).

CONCLUSIONS

Parental history of type 2 diabetes is associated with a later onset of type 1 diabetes, the metabolic syndrome, and a metabolic profile related to insulin resistance.

Metabolic phenotypes, vascular complications, and premature deaths in a population of 4,197 patients with type 1 diabetes

OBJECTIVE

Poor glycemic control, elevated triglycerides, and albuminuria are associated with vascular complications in diabetes. However, few studies have investigated combined associations between metabolic markers, diabetic kidney disease, retinopathy, hypertension, obesity, and mortality. Here, the goal was to reveal previously undetected association patterns between clinical diagnoses and biochemistry in the FinnDiane dataset.

RESEARCH DESIGN AND METHODS

At baseline, clinical records, serum, and 24-h urine samples of 2,173 men and 2,024 women with type 1 diabetes were collected. The data were analyzed by the self-organizing map, which is an unsupervised pattern recognition algorithm that produces a two-dimensional layout of the patients based on their multivariate biochemical profiles. At follow-up, the results were compared against all-cause mortality during 6.5 years (295 deaths).

RESULTS

The highest mortality was associated with advanced kidney disease. Other risk factors included 1) a profile of insulin resistance, abdominal obesity, high cholesterol, triglycerides, and low HDL(2) cholesterol, and 2) high adiponectin and high LDL cholesterol for older patients. The highest population-adjusted risk of death was 10.1-fold (95% CI 7.3-13.1) for men and 10.7-fold (7.9-13.7) for women. Nonsignificant risk was observed for a profile with good glycemic control and high HDL(2) cholesterol and for a low cholesterol profile with a short diabetes duration.

CONCLUSIONS

The self-organizing map analysis enabled detailed risk estimates, described the associations between known risk factors and complications, and uncovered statistical patterns difficult to detect by classical methods. The results also suggest that diabetes per se, without an adverse metabolic phenotype, does not contribute to increased mortality.

Clustering of risk factors in parents of patients with type 1 diabetes and nephropathy

OBJECTIVE

To assess the impact of parental risk factors for diabetic nephropathy.

RESEARCH DESIGN AND METHODS

This cross-sectional study included 2,355 type 1 diabetic patients from the FinnDiane (Finnish Diabetic Nephropathy) study. Diabetic nephropathy was defined as macroalbuminuria (urinary albumin excretion rate >200 microg/min or >300 mg/24 h) or end-stage renal disease. Information was available from 4,676 parents. Parental scores were calculated based on the number of various traits in the parents.

RESULTS

Patients with diabetic nephropathy, compared with those without diabetic nephropathy, had a higher prevalence of maternal (41 vs. 35%, P = 0.046) and parental (62 vs. 55%, P = 0.044) hypertension, maternal stroke (7.6 vs. 5.1%, P = 0.044), and maternal (1.4 vs. 0.7%, P = 0.058) and parental (4.3 vs. 2.9%, P = 0.030) type 1 diabetes. If both, compared with none, of the parents had hypertension, the adjusted odds ratio (OR) for diabetic nephropathy in offspring was 1.56 (95% CI 1.13-2.15). The adjusted OR for diabetic nephropathy was 2.13 (1.36-3.33) for the parental hypertension-diabetes score (3-4 vs. 0 points) and 2.13 (1.37-3.33) for the parental hypertension-cardiovascular disease (CVD)-diabetes score (4-6 vs. 0 points). Fathers of patients with diabetic nephropathy, compared with those without diabetic nephropathy, had reduced overall survival (log-rank P = 0.04) and reduced cardiovascular survival (log-rank P = 0.03).

CONCLUSIONS

A cluster of parental hypertension, CVD, and diabetes is associated with diabetic nephropathy in type 1 diabetes, as is paternal mortality.

Metabolic syndrome in type 1 diabetes: association with diabetic nephropathy and glycemic control (the FinnDiane study)

OBJECTIVE

The aim of this study was to estimate the prevalence of the metabolic syndrome in Finnish type 1 diabetic patients and to assess whether it is associated with diabetic nephropathy or poor glycemic control.

RESEARCH DESIGN AND METHODS

In all, 2,415 type 1 diabetic patients (51% men, mean age 37 years, duration of diabetes 22 years) participating in the nationwide, multicenter Finnish Diabetic Nephropathy (FinnDiane) study were included. Metabolic syndrome was defined according to the National Cholesterol Education Program diagnostic criteria. Patients were classified as having normal albumin excretion rate (AER) (n = 1,261), microalbuminuria (n = 326), macroalbuminuria (n = 383), or end-stage renal disease (ESRD) (n = 164). Glycemic control was classified as good (HbA1c <7.5%), intermediate (7.5-9.0%), or poor (>9.0%). Creatinine clearance was estimated with the Cockcroft-Gault formula.

RESULTS

The overall prevalence of metabolic syndrome was 38% in men and 40% in women. The prevalence was 28% in those with normal AER, 44% in microalbuminuric patients, 62% in macroalbuminuric patients, and 68% in patients with ESRD (P < 0.001). Patients with metabolic syndrome had a 3.75-fold odds ratio for diabetic nephropathy (95% CI 2.89-4.85), and all of the separate components of the syndrome were independently associated with diabetic nephropathy. The prevalence of metabolic syndrome was 31% in patients with good glycemic control, 36% in patients with intermediate glycemic control, and 51% in patients with poor glycemic control (P < 0.001). Similarly, metabolic syndrome increased with worsening creatinine clearance.

CONCLUSIONS

The metabolic syndrome is a frequent finding in type 1 diabetes and increases with advanced diabetic nephropathy and worse glycemic control.