Incidence of diabetic nephropathy in Type 1 diabetic patients in Spain: 'Estudio Diamante'

Progression and regression of kidney disease in type 1 diabetes

Diabetic kidney disease is distinguished by the presence of albuminuria, hypertension, declining kidney function, and a markedly elevated cardiovascular disease risk. This constellation of clinical features drives the premature mortality associated with type 1 diabetes. The first epidemiological investigations concerning type 1 diabetes-related albuminuria date back to the 1980s. The early studies found that proteinuria - largely equivalent to severe albuminuria - developed in 35 to 45% of individuals with type 1 diabetes, with the diabetes duration-specific incidence rate pattern portraying one or two peaks. Furthermore, moderate albuminuria, the first detectable sign of diabetic kidney disease, was found to nearly inexorably progress to overt kidney disease within a short span of time. Since the early reports, studies presenting more updated incidence rates have appeared, although significant limitations such as study populations that lack broad generalizability, study designs vulnerable to substantive selection bias, and constrained follow-up times have been encountered by many. Nevertheless, the most recent reports estimate that in modern times, moderate - instead of severe - albuminuria develops in one-third of individuals with type 1 diabetes; yet, a considerable part (up to 40% during the first ten years after the initial albuminuria diagnosis) progresses to more advanced stages of the disease over time. An alternative pathway to albuminuria progression is its regression, which affects up to 60% of the individuals, but notably, the relapse rate to a more advanced disease stage is high. Whether albuminuria regression translates into a decline in cardiovascular disease and premature mortality risk is an area of debate, warranting more detailed research in the future. Another unclear but alarming feature is that although the incidence of severe albuminuria has fallen since the 1930s, the decline seems to have reached a plateau after the 1980s. This stagnation may be due to the lack of kidney-protective medicines since the early 1980s, as the recent breakthroughs in type 2 diabetes have not been applicable to type 1 diabetes. Therefore, novel treatment strategies are at high priority within this patient population.

Incidence of chronic kidney disease among people with diabetes: a systematic review of observational studies

AIMS

The aim was to systematically review published articles that reported the incidence of chronic kidney disease among people with diabetes.

METHODS

A systematic literature search was performed using MEDLINE, Embase and CINAHL databases. The titles and abstracts of all publications identified by the search were reviewed and 10 047 studies were retrieved.

RESULTS

A total of 71 studies from 30 different countries with sample sizes ranging from 505 to 211 132 met the inclusion criteria. The annual incidence of microalbuminuria and albuminuria ranged from 1.3% to 3.8% for Type 1 diabetes. For Type 2 diabetes and studies combining both diabetes types, the range was from 3.8% to 12.7%, with four of six studies reporting annual rates between 7.4% and 8.6%. In studies reporting the incidence of eGFR < 60 ml/min/1.73 m² using the Modification of Diet on Renal Disease (MDRD) equation, apart from one study which reported an annual incidence of 8.9%, the annual incidence ranged from 1.9% to 4.3%. The annual incidence of end-stage renal disease ranged from 0.04% to 1.8%.

CONCLUSIONS

The annual incidence of microalbuminuria and albuminuria is ~ 2-3% in Type 1 diabetes, and ~ 8% in Type 2 diabetes or mixed diabetes type. The incidence of developing eGFR < 60 ml/min/1.73 m² is ~ 2-4% per year. Despite the wide variation in methods and study design, within a particular category of kidney disease, there was only modest variation in incidence rates. These findings may be useful in clinical settings to help understand the risk of developing kidney disease among those with diabetes.

Epidemiology of diabetic kidney disease in adult patients with type 1 diabetes in Italy: The AMD-Annals initiative

BACKGROUND

Patients with type 1 diabetes mellitus are at increased risk of death. This risk appears to be modulated by kidney dysfunction. The aim of this study was to evaluate the prevalence of diabetic kidney disease (DKD), its traits, and clinical correlates in a large sample of patients with type 1 diabetes.

METHODS

Clinical data of 20 464 patients with type 1 diabetes were extracted from electronic medical records. Estimated glomerular filtration rate (eGFR) and increased urinary albumin excretion were considered.

RESULTS

Mean age of the patients was 46 ± 16 years, 55.0% were males, and duration of diabetes 19 ± 13 years. The frequency of diabetic kidney disease, low eGFR, and albuminuria was 23.5%, 8.1%, and 19.5%, respectively. In the multivariate analysis the presence of diabetic kidney disease was associated with age (odds ratio [OR] = 1.14, 95% confidence interval [CI]: 1.10-1.18), duration of diabetes (OR = 1.05, 95% CI: 1.03-1.07), and worse glycemic control (OR = 1.24, 95% CI: 1.21-1.28, for every 1% glycated hemoglobin increase). Diabetic kidney disease was also independently associated with an atherogenic lipid profile and increased systolic blood pressure. Glucose control, systolic blood pressure, triglycerides, and high density lipoprotein cholesterol were associated with both low eGFR and albuminuria. Male gender, retinopathy and smoke were related to albuminuria, being female was related to low eGFR, while SUA levels were associated with DKD, low eGFR and albuminuria.

CONCLUSIONS

In our sample of patients with type 1 diabetes, diabetic kidney disease entails an unsafe cardiovascular risk profile. Hyperglycemia, arterial hypertension, and atherogenic lipid profile affected both low eGFR and albuminuria. Retinopathy and smoking were related only to albuminuria while being female and elevated serum uric acid were associated only with low eGFR.

HDL cholesterol and risk of diabetic nephropathy in patient with type 1 diabetes: A meta-analysis of cohort studies

A meta-analysis was conducted to assess the impact of HDL on risk of diabetic nephropathy in T1DM patients. Ten papers containing (7698) participants were included in this meta-analysis. Our meta-analysis suggest that the risk of diabetic nephropathy was decreased with HDL in type 1 diabetes.

Prevalence of abnormal urinary albumin excretion in a population-based study in Spain: results from the HERMEX Study

BACKGROUND

HERMEX is a population-based study which try to evaluate the relative weight of cardiovascular risk factors in the population of Extremadura. This report provides the data obtained about microalbuminuria in a large Spanish population.

DESIGN AND METHODS

Observational, cross-sectional, population-based study. A total of 3402 subjects were randomly selected from the Health Care System of Extremadura. The final sample included 2813 subjects (mean age 51·2 years, 53·5% female). Urinary albumin excretion rate (UAER) in first morning urine sample was analysed. Microalbuminuria was diagnosed when UAER was ≥ 22 in men or ≥ 31 mg/g in women.

RESULTS

Prevalence of abnormal UAER in general population was 5·5% (microalbuminuria: 4·7%; proteinuria 0·8%). Microalbuminuria grew slightly in patients between 65 and 74 years and showed a dramatic increase in subject older than 75 years (P < 0·001). Men showed a high prevalence of microalbuminuria (5·8% vs. women 3·6%; P = 0·006 chi-squared test). Increased UAER was more common in obese subjects (6·7% vs. 2·3%, P < 0·001), hypertensive patients (8·3% vs. 2·3%, P < 0·001) and diabetic ones (10·9% vs. 3·7%, P < 0·001). The multivariate analysis showed a positive correlation of abnormal UAER with body mass index (BMI), systolic blood pressure, plasma creatinine and triglyceride levels.

CONCLUSIONS

A low frequency of abnormal UAER was detected in a randomly selected sample of Spanish general population. This finding agreed with the low rates of cardiovascular mortality and morbidity observed in Spain in spite of a high prevalence of classic cardiovascular risk factors.

Identifying genetic susceptibilities to diabetes-related complications among individuals at low risk of complications: An application of tree-structured survival analysis

The authors hypothesized that genetic predisposition to diabetes complications would be more evident among low-risk individuals and aimed to identify genes related to developing complications (confirmed distal symmetric polyneuropathy, overt nephropathy, or coronary artery disease) in low-risk groups. Participants in the Pittsburgh, Pennsylvania, Epidemiology of Diabetes Complications Study of childhood-onset type 1 diabetes, first seen in 1986-1988 (mean age, 28 years; diabetes duration, 19 years), were reexamined biennially for 10 years. For each complication, subgroups with the lowest disease risk were identified by using tree-structured survival analysis, and 15 candidate genes were compared between subjects with and without complications. In the group with the lowest incidence of confirmed distal symmetric polyneuropathy (n = 123), confirmed distal symmetric polyneuropathy risk increased fivefold for those with the eNOS GG genotype (p < 0.05). In the group with the lowest risk of overt nephropathy (n = 340), the ACE D polymorphism increased overt nephropathy risk twofold (p = 0.05), whereas a protective effect was observed for the LIPC CC genotype (p < 0.05). In the group with the lowest incidence of coronary artery disease (n = 331), the MTHFR CC genotype increased coronary artery disease risk threefold (p < 0.05). Tree-structured survival analysis may help identify genetic predispositions among individuals who, despite low risk, develop diabetes-related complications.

Microalbuminuria en pacientes diabéticos y en pacientes con hipertensión arterial: estudio de una cohorte de 979 pacientes

BACKGROUND AND OBJECTIVE

Microalbuminuria is a known complication of diabetes mellitus but it is also a cardiovascular risk factor commonly present among hypertensive (non diabetic) population. The prevalence of microalbuminuria is variable and it has been never estimated in our region. The aim of this study has been to determine the prevalence of microalbuminuria in hypertensive (non diabetic) and diabetic population in Extremadura (Spain).

PATIENTS AND METHOD

The study included diabetic patients and non-diabetic hypertensive ones randomly selected. Microalbuminuria was measured in every patient using albumin/creatinin reactive stick in fasting first morning urine. Whenever possible microalbuminuria was confirmed in laboratory by microalbuminuria/creatinina coefficient in first morning urine samples.

RESULTS

A total of 979 patients (mean age [SD], 67.9 [10.8] years; 409 men and 570 women, 505 diabetics) were studied. The presence of microalbuminuria was found in 12.4% of hypertensive patients and in 21.4% of diabetic patients (p < 0.001). Hypertensives and normotensive diabetics showed a similar prevalence of microalbuminuria (13.3%, not significant), but it tripled in hypertensive diabetics (33.8; p < 0.01). Glicemic control was not different for microalbuminuric diabetic patients and non microalbuminuric ones. The patients receiving rennin-angiotensin axis blocking drugs do not showed less prevalence of microalbuminuria (hypertensives 10.5%, diabetics 23.5%). Microalbuminuria was confirmed in 65.4% of patients.

CONCLUSIONS

The prevalence of microalbuminuria in Extremadura seems to be high either in diabetics or non diabetic hypertensive patients. The finding of microalbuminuria in diabetics patients correlates with hypertension but do not with glicemic control. The prevalence of microalbuminuria is high in spite of using rennin-angiotensin axis blocking drugs.

Factores que influyen en la aparición de la nefropatía diabética incipiente: estudio ESODIAH

BACKGROUND AND OBJECTIVE

High cholesterol levels might contribute to the presence of albuminuria. The objective of our study was to evaluate the influence of lipid levels on the development of incipient diabetic nephropathy. Secondary objectives were to evaluate the effects of diabetes control, high blood pressure, age, sex, years of diabetes evolution, body mass index and smoking.

PATIENTS AND METHOD

930 subjects were enrolled in an open observational prospective cohort study of subjects with type 2 diabetes mellitus and high cholesterol levels (ESODIAH study) for 2 years. In our nephropathy study we selected 590 patients who had albuminuria measurements done. In every 4-month interval visit we made a clinical evaluation and blood analysis including HbA1c, lipid profile and microalbuminuria. Statistical analysis included t-Student, chi2 test, and binary logistic regressions.

RESULTS

51.7% men, aged 62.08 years of age and with an evolution of their diabetes of 8.49 years were studied. 40.6% had microalbuminuria and 59.4% had normoalbuminuria. High HbA1c correlated with the presence of albuminuria (odds ratio [OR] = 1.3; 95% confidence interval [CI], 1.12-1.55; p = 0.001). The development of microalbuminuria was more frequent in younger (OR = 0.93; 95% CI, 0.89-0.98), smoker (OR = 3.19; 95% CI, 1.02-9.96), subjects with high systolic blood pressure (OR = 1.02; 95% CI, 1-1.05). Total cholesterol levels at the end of the study were higher in new microalbuminuric (group I) than normoalbuminuric patients (group II) (group I: 211.08 [34.75] mg/dl vs group II: 200.67 [30.50]; p = 0.042).

CONCLUSIONS

Tobacco, blood pressure and diabetes control influences the presence and development of microalbuminuria. More studies are required to study the influence of hypercholesterolemia.