Cigarette smoking and increased urine albumin excretion are interrelated predictors of nephropathy progression in type 2 diabetes

Risk factors associated with the development of diabetic kidney disease in Sudanese patients with type 2 diabetes mellitus: A case-control study

BACKGROUND AND AIMS

Limited data are available regarding the risk factors associated with the development of diabetic kidney disease (DKD) among Sudanese adults with type 2 diabetes mellitus (T2DM).

METHODS

A case-control study was conducted at Dr. Salma Center for Kidney Diseases between April and September 2019. Patients with T2DM and DKD were compared to age and sex-matched T2DM patients with no kidney disease (NKD). Socio-demographic features, clinical findings, and laboratory investigations of the study subjects and controls were analyzed using SPSS.

RESULTS

A total of 372 patients with DKD were compared to 364 T2DM patients with NKD. The mean age of the DKD patients was 58 ± 13.4 years, their median eGFR was 37.3 ± 4.9 ml/min/1.73 m²; they had their T2DM at a significantly younger age compared to controls (P = 0.014). Logistic regression analysis revealed that a family history of diabetes mellitus, a family history of chronic kidney disease, the presence of hypertension, obesity, hypercholesterolemia, hyperuricemia, smoking, recurrent urinary tract infection, and the regular use of non-steroidal anti-inflammatory drugs were significantly associated with the development of DKD (P values < 0.05).

CONCLUSION

A series of modifiable risk factors were found to be significant determinants for developing DKD. Primary care physicians are expected to pay considerable attention to their control.

Association of smoking and cardiometabolic parameters with albuminuria in people with type 2 diabetes mellitus: a systematic review and meta-analysis

AIMS

Smoking is a strong risk factor for albuminuria in people with type 2 diabetes mellitus (T2DM). However, it is unclear whether this sequela of smoking is brought about by its action on cardiometabolic parameters or the relationship is independent. The aim of this systematic review is to explore this relationship.

METHODS

Electronic databases on cross-sectional and prospective studies in Medline and Embase were searched from January 1946 to May 2018. Adult smokers with T2DM were included, and other types of diabetes were excluded.

RESULTS

A random effects meta-analysis of 20,056 participants from 13 studies found that the odds ratio (OR) of smokers developing albuminuria compared to non-smokers was 2.13 (95% CI 1.32, 3.45). Apart from smoking, the odds ratio of other risk factors associated with albuminuria were: age 1.24 (95% CI 0.84, 1.64), male sex 1.39 (95% CI 1.16, 1.67), duration of diabetes 1.78 (95% CI 1.32, 2.23), HbA1c 0.63 (95% CI 0.45, 0.81), SBP 6.03 (95% CI 4.10, 7.97), DBP 1.85 (95% CI 1.08, 2.62), total cholesterol 0.06 (95% CI - 0.05, 0.17) and HDL cholesterol - 0.01 (95% CI - 0.04, 0.02), triglyceride 0.22 (95% CI 0.12, 0.33) and BMI 0.40 (95% CI 0.00-0.80). When the smoking status was adjusted in a mixed effect meta-regression model, the duration of diabetes was the only statistically significant factor that influenced the prevalence of albuminuria. In smokers, each year's increase in the duration of T2DM was associated with an increased risk of albuminuria of 0.19 units (95% CI 0.07, 0.31) on the log odds scale or increased the odds approximately by 23%, compared to non-smokers. Prediction from the meta-regression model also suggested that the odds ratios of albuminuria in smokers after a diabetes duration of 9 years and 16 years were 1.53 (95% CI 1.10, 2.13) and 5.94 (95% CI 2.53, 13.95), respectively.

CONCLUSIONS

Continuing to smoke and the duration of diabetes are two strong predictors of albuminuria in smokers with T2DM. With a global surge in younger smokers developing T2DM, smoking cessation interventions at an early stage of disease trajectory should be promoted.

Smoking and diabetes: dangerous liaisons and confusing relationships

The combined harmful effects of cigarette smoking and hyperglycemia can accelerate vascular damage in patients with diabetes who smoke, as is well known. Can smoking cause diabetes? What are the effects of smoking on macro and microvascular complications? Now growing evidence indicates that regular smokers are at risk of developing incident diabetes. Since the prevalence rates of smoking in patients with diabetes are relatively similar to those of the general population, it is essential to address the main modifiable risk factor of smoking to prevent the onset of diabetes and delay the development of its complications. Quitting smoking shows clear benefits in terms of reducing or slowing the risk of cardiovascular morbidity and mortality in people with diabetes. Does quitting smoking decrease the incidence of diabetes and its progression? What are the effects of quitting smoking on complications? The current evidence does not seem to unequivocally suggest a positive role for quitting in patients with diabetes. Quitting smoking has also been shown to have a negative impact on body weight, glycemic control and subsequent increased risk of new-onset diabetes. Moreover, its role on microvascular complications of the disease is unclear. What are the current smoking cessation treatments, and which ones are better for patients with diabetes? Stopping smoking may be of value for diabetes prevention and management of the disease and its macrovascular and microvascular complications. Unfortunately, achieving long-lasting abstinence is not easy and novel approaches for managing these patients are needed. This narrative review examines the evidence on the impact of smoking and smoking cessation in patients with diabetes and particularly in type 2 diabetes mellitus and its complications. In addition, management options and potential future directions will be discussed.

Interaction of MTHFR C677T polymorphism with smoking in susceptibility to diabetic nephropathy in Chinese men with type 2 diabetes

We investigated the interaction of MTHFR C677T polymorphism (rs1801133) with smoking in susceptibility to diabetic nephropathy (DN) in Chinese men with type 2 diabetes mellitus (T2DM). We studied 655 Chinese men with T2DM, who were divided into two groups (321 with DN and 334 without DN). The genotype of MTHFR C677T polymorphism was detected by real-time polymerase chain reaction. MTHFR TT genotype carried a higher risk of DN compared with the CC genotype (OR = 2.05; P = 0.002). The T allele showed marked association with DN development in patients who smoked, using additive, recessive, and dominant models (OR = 1.60, 1.83, and 1.88, respectively; P = 0.006, 0.002, and 0.04, respectively), which was not observed in the nonsmoking group. Patients with TT and CT genotypes, who smoked had a higher risk of DN compared with the control group (non-smoking with CC genotype; OR = 3.73 and 2.28, respectively; P < 0.001 and P = 0.004, respectively), whereas the other groups were not observed. In conclusion, the T allele of rs1801133 may be a risk factor for DN in Chinese men with T2DM, and synergy appears to exist between the MTHFR rs1801133 and smoking in susceptibility to DN.

Cigarette Smoking, Diabetes, and Diabetes Complications: Call for Urgent Action

PURPOSE OF REVIEW

This review aimed to examine the latest evidence linking cigarette smoking and cessation to risk of incident diabetes and its complications.

RECENT FINDINGS

Abundant evidence has demonstrated that smoking is associated with increased risk of type 2 diabetes and cardiovascular disease among diabetic patients, while its relationship with microvascular complications is more limited to diabetic nephropathy and neuropathy in type 1 diabetes. In addition, diabetes risk remains high in the short term after smoking cessation, while it reduces gradually in the long term. Risk of cardiovascular complications also substantially decreases after quitting smoking, but results for microvascular complications are not consistent. Smoking is associated with increased risks of incident diabetes in the general population and cardiovascular complications among diabetic patients. Although the short-term post-cessation diabetes risk needs to be acknowledged, this review calls for urgent action to implement population-wide policies and individual pharmaceutical and lifestyle interventions (if evidence accumulated in future) to aid smoking cessation and prevent diabetes and its complications.

Predictors of chronic kidney disease in type 1 diabetes: a longitudinal study from the AMD Annals initiative

We evaluated 2,656 patients with type 1 diabetes mellitus and preserved renal function from the database of the Italian Association of Clinical Diabetologists network to identify clinical predictors for the development of chronic kidney disease. We measured estimated glomerular filtration rate (eGFR), urinary albumin excretion, HbA1c, lipids, blood pressure. Over a 5-year period 4.3% (n = 115) developed reduced eGFR (<60 ml/min/1.73 m²), 18.0% (n = 477) albuminuria, and 21.0% (n = 559) either one of the renal endpoints (CKD). Odds ratios for eGFR below 90 mL/min/1.73 m2 (1.48, P < 0.001), HbA1c (1.13, P = 0.002), triglycerides (1.04, P = 0.021 by 20 mg/dL), low density lipoprotein cholesterol (LDL-c) (0.95, P = 0.002 by 10 mg/dL) were independently related to the onset of CKD. Known duration of diabetes (1.15, P = 0.014 by 10 years), HbA1c (1.16, P = 0.001), triglycerides (1.05, P = 0.005 by 20 mg/dL), LDL-c (0.95, P = 0.003 by 10 mg/dL), antihypertensive treatment (2.28, P = 0.018) were related to the onset of albuminuria while age and presence of baseline eGFR values between 90 and 60 mL/min/1.73 m2, independently affected the developing of reduced eGFR (OR 1.95, P < 0.001 by 10 years and 2.92, P < 0.001). Patients with type 1 diabetes mellitus and unfavorable CV risk profile are at high risk of developing CKD. The two main traits of CKD share several determinants, although with some specificities.

Levocarnitine and Dialysis: A Review

Among the various metabolic abnormalities documented in dialysis patients are abnormalities related to the metabolism of fatty acids. Aberrant fatty-acid metabolism has been associated with the promotion of free-radical production, insulin resistance, and cellular apoptosis. These processes have been identified as important contributors to the morbidity experienced by dialysis patients. There is evidence that levocarnitine supplementation can modify the deleterious effects of defective fatty-acid metabolism. Patients receiving hemodialysis and, to a lesser degree, peritoneal dialysis have been shown to be carnitine deficient, as manifested by reduced levels of plasma free carnitine and an increase in the acyl:free carnitine ratio. Cardiac and skeletal muscles are particularly dependent on fatty-acid metabolism for the generation of energy. A number of clinical abnormalities have been correlated with a low plasma carnitine status in dialysis patients. Clinical trials have examined the efficacy of levocarnitine therapy in a number of conditions common in dialysis patients, including skeletal-muscle weakness and fatigue, cardiomyopathy, dialysis-related hypotension, hyperlipidemia, and anemia poorly responsive to recombinant human erythropoietin therapy (rHuEPO). This review examines the evidence for carnitine deficiency in patients requiring dialysis, and documents the results of relevant clinical trials of levocarnitine therapy in this population. Consensus recommendations by expert panels are summarized and contrasted with present guidelines for access to levocarnitine therapy by dialysis patients.

Carnitine Treatment Improved Quality-of-Life Measure in a Sample of Midwestern Hemodialysis Patients

BACKGROUND

Previously, we demonstrated that selected groups of hemodialysis patients might be more likely to have abnormalities of carnitine metabolism. The purpose of the present study was to examine the effects of carnitine therapy in these selected groups of hemodialysis patients on quality-of-life measures and erythropoietin dose.

METHODS

This was a double-blind, randomized, controlled trial, in which 50 hemodialysis patients were treated with either 2 g i.v. carnitine or placebo. The treatment period was for 24 weeks.

RESULTS

Thirty-four patients (15 in the treatment group) completed the study. The mean age was 69 +/- 15 years, 35% were women, and 44% had diabetes. Mean initial plasma total, free, short-chain acyl and long-chain acyl carnitine concentrations (micromol/L; mean +/- SEM) were 35.9 +/- 1.8, 18.2 +/- 1.1, 11.6 +/- 0.6, and 6.0 +/- 0.3, whereas the plasma acyl-to-free-carnitine ratio was 1.02 +/- 0.05. With respect to the Medical Outcomes Short Form-36 (SF-36), improvements from baseline were noted in the treatment group (n = 13) for role-physical (33.9 +/- 1.9 to 43.2 +/- 3.0, p < .05) and the SF-36 physical component summary score (36.1 +/- 2.7 to 39.7 +/- 2.3, p = .09) relative to changes in the control group (n = 14). The erythropoietin dose over the 24-week period was reduced from baseline in the treatment group relative to the placebo group (-1.62 +/- 0.91 vs 1.33 +/- 0.79 units erythropoietin/dry weight/hemoglobin concentration, respectively, p < .05).

CONCLUSIONS

After 24 weeks of i.v. carnitine therapy, SF-36 scores were improved and erythropoietin doses were reduced in hemodialysis patients, relative to the control group.

The Association Between Smoking Tobacco After a Diagnosis of Diabetes and the Prevalence of Diabetic Nephropathy in the Korean Male Population

Objectives:

Smoking is known to be associated with nephropathy in patients with diabetes. The distinct effects of smoking before and after diabetes has been diagnosed, however, are not well characterized. We evaluated the association of cigarette smoking before and after a diagnosis of diabetes with the presence of diabetic nephropathy.

Methods:

We analyzed data from the 2011-2013 editions of the Korea National Health and Nutrition Examination Survey. A total of 629 male patients diagnosed with diabetes were classified as non-smokers (90 patients), former smokers (225 patients), or continuing smokers (314 patients). A “former smoker” was a patient who smoked only before receiving his diagnosis of diabetes. A “continuing smoker” was a patient who smoked at any time after his diabetes had been diagnosed. Diabetic nephropathy was defined as the presence of albuminuria (spot urine albumin/creatinine ratio ≥30 mg/g) or low estimated glomerular filtration rate (<60 mL/min/1.73 m²). Multiple logistic regression models were used to assess the independent association after adjusting for age, duration of diabetes, hemoglobin A1c, body mass index, systolic blood pressure, medication for hypertension, and medication for dyslipidemia. Female patients were excluded from the study due to the small proportion of females in the survey who smoked.

Results:

Compared to non-smokers, continuing smokers had significantly higher odds ratio ([OR], 2.17; 95% confidence interval [CI], 1.23 to 3.83) of suffering from diabetic nephropathy. The corresponding OR (95% CI) for former smokers was 1.26 (0.70 to 2.29).

Conclusions:

Smoking after diagnosis of diabetes is significantly associated with the presence of diabetic nephropathy in the Korean male population.

Hypoxia: The Force that Drives Chronic Kidney Disease

In the United States the prevalence of end-stage renal disease (ESRD) reached epidemic proportions in 2012 with over 600,000 patients being treated. The rates of ESRD among the elderly are disproportionally high. Consequently, as life expectancy increases and the baby-boom generation reaches retirement age, the already heavy burden imposed by ESRD on the US health care system is set to increase dramatically. ESRD represents the terminal stage of chronic kidney disease (CKD). A large body of evidence indicating that CKD is driven by renal tissue hypoxia has led to the development of therapeutic strategies that increase kidney oxygenation and the contention that chronic hypoxia is the final common pathway to end-stage renal failure. Numerous studies have demonstrated that one of the most potent means by which hypoxic conditions within the kidney produce CKD is by inducing a sustained inflammatory attack by infiltrating leukocytes. Indispensable to this attack is the acquisition by leukocytes of an adhesive phenotype. It was thought that this process resulted exclusively from leukocytes responding to cytokines released from ischemic renal endothelium. However, recently it has been demonstrated that leukocytes also become activated independent of the hypoxic response of endothelial cells. It was found that this endothelium-independent mechanism involves leukocytes directly sensing hypoxia and responding by transcriptional induction of the genes that encode the β2-integrin family of adhesion molecules. This induction likely maintains the long-term inflammation by which hypoxia drives the pathogenesis of CKD. Consequently, targeting these transcriptional mechanisms would appear to represent a promising new therapeutic strategy.

The functional Q84R polymorphism of TRIB3 gene is associated with diabetic nephropathy in Chinese type 2 diabetic patients

Increased oxidative stress and circulating free fatty acids (FFA) has been suggested to involve in the pathogenesis of diabetic nephropathy. TRIB3 can inhibit FFA and reactive oxygen species (ROS) stimulated podocyte production of MCP-1. Smoking increases the production of reactive oxygen species, which accelerates oxidative stress under hyperglycemia. To determine whether the Q84R polymorphism (rs2295490), alone or in combination with smoking, contributes to the development of diabetic nephropathy, a case-control study was performed in 812 Chinese patients with type 2 diabetes. Among patients, 214 had diabetic nephropathy with microalbuminuria (n=156) or overt albuminuria (n=58), and 598 did not show either of these symptoms but had diabetes for ≥10 years and were not undergoing antihypertension treatment. After adjustment for confounders, TRIB3 single-nucleotide polymorphism rs2295490 was associated with DN (OR 1.318, 95% CI 1.075, 1.653, p=0.017); smoking was also an independent risk factor for diabetic nephropathy (1.42 [1.25-2.04], p<0.001). In addition, we identified possible synergistic effects; i.e., the high-risk group (smokers with the AG+GG genotype) showed 2.13 times higher risk (1.51-3.96, p<0.001) of diabetic nephropathy than the low-risk group (nonsmokers with the AA genotype) in a multiple logistic regression analysis controlled for the confounders, but no departure from additivity was found. Our results indicate that smoking and the TRIB3 G-allele is associated with an increased risk of diabetic nephropathy, which supports the hypothesis that oxidative stress contributes to the development of diabetic nephropathy.

Effects of switching from oral administration to intravenous injection of l-carnitine on lipid metabolism in hemodialysis patients

Background

Carnitine deficiency may contribute to cardiovascular disease (CVD) in patients with hemodialysis (HD). Dyslipidemia plays a role in CVD and its prevalence is also high in HD patients. We examined here the effects of switching from oral administration (PO) to intravenous (IV) injection of l-carnitine on lipid metabolism in patients with HD.

Methods

Nine HD patients who had received l-carnitine orally (900 mg/day) for 1 year were enrolled in this study. We examined whether lipid parameters were improved by switching to IV injection therapy of 1000 mg l-carnitine.

Results

IV injection of l-carnitine for 1 week significantly increased total, free and acyl carnitine levels both before and after HD. Switching to IV injection therapy for 1 and 4 weeks decreased serum free fatty acid (FFA) (322 ± 104 versus 261 ± 124 µmol/L) and increased high-density lipoprotein-cholesterol levels (1.46 ± 0.49 versus 1.63 ± 0.62 mmol/L), respectively. Change in FFA values from the baseline (ΔFFA) was positively correlated with the Δacyl/free carnitine ratio (r² = 0.553, P = 0.022).

Conclusion

This study demonstrated that switching to IV l-carnitine therapy from oral supplementation improved lipid profiles, thus supporting the clinical utility of IV administration of l-carnitine for the treatment of patients on HD.

Kidney dysfunction and related cardiovascular risk factors among patients with type 2 diabetes

BACKGROUND

Kidney dysfunction is a strong predictor of end-stage renal disease and cardiovascular (CV) events. The main goal was to study the clinical correlates of diabetic kidney disease in a large cohort of patients with type 2 diabetes mellitus (T2DM) attending 236 Diabetes Clinics in Italy.

METHODS

Clinical data of 120 903 patients were extracted from electronic medical records by means of an ad hoc-developed software. Estimated glomerular filtration rate (GFR) and increased urinary albumin excretion were considered. Factors associated with the presence of albuminuria only, GFR < 60 mL/min/1.73 m(2) only or both conditions were evaluated through multivariate analysis.

RESULTS

Mean age of the patients was 66.6 ± 11.0 years, 58.1% were male and mean duration of diabetes was 11.1 ± 9.4 years. The frequency of albuminuria, low GFR and both albuminuria and low GFR was 36.0, 23.5 and 12.2%, respectively. Glycaemic control was related to albuminuria more than to low GFR, while systolic and pulse pressure showed a trend towards higher values in patients with normal kidney function compared with those with both albuminuria and low GFR. Multivariate logistic analysis showed that age and duration of disease influenced both features of kidney dysfunction. Male gender was associated with an increased risk of albuminuria. Higher systolic blood pressure levels were associated with albuminuria, with a 4% increased risk of simultaneously having albuminuria and low GFR for each 5 mmHg increase.

CONCLUSIONS

In this large cohort of patients with T2DM, reduced GFR and increased albuminuria showed, at least in part, different clinical correlates. A worse CV risk profile is associated with albuminuria more than with isolated low GFR.

Associations of baseline characteristics with evolution of eGFR in a referred chronic kidney disease cohort

BACKGROUND

Currently, most chronic kidney disease (CKD) classifications identify patients at different stages of CKD but do not identify risk of progression or adverse outcome. This analysis aims to describe associations between baseline characteristics and the evolution of estimated glomerular filtration rate (eGFR) and identify threshold values for clinical parameters that maximally discriminate progression to renal replacement therapy (RRT) in a referred cohort of patients with CKD stages 3-5.

DESIGN AND METHODS

A longitudinal mixed-effect model was used to determine annualized estimated change in eGFR and classification tree analysis to identify threshold values that maximally discriminate progression to RRT.

RESULTS

A total of 1316 patients were available for analysis with median follow-up of 33 months (interquartile range 20-60). Mixed model analysis suggested that the underlying diagnoses of autosomal dominant polycystic kidney disease and diabetic nephropathy exhibited on average a 2.7 (0.3) and 0.7 (0.3) ml/min/year faster rate of decline in eGFR, respectively, compared to those patients with biopsy-proven glomerulonephritis. In the regression tree analysis, we attempted to identify threshold values for clinical parameters that maximally discriminate progression to RRT. eGFR ≤24 ml/min was the first ranked discriminator, diastolic blood pressure appeared in the second and fourth rounds, eGFR appeared again in the third round together with cholesterol and systolic blood pressure, with basal metabolic index in the fourth.

CONCLUSION

This analysis highlights risk factors for progressive kidney disease and demonstrates the variability in evolution of eGFR across the cohort as well as the importance of underlying renal disease type on the progression of CKD.

Nicotine signaling and progression of chronic kidney disease in smokers

The deleterious health effects of cigarette smoking are far reaching, and it remains the most important modifiable risk factor for improving overall morbidity and mortality. In addition to being a risk factor for cancer, cardiovascular disease and lung disease, there is strong evidence, both from human and animal studies, demonstrating a role for cigarette smoking in the progression of chronic kidney disease (CKD). Clinical studies have shown a strong correlation between cigarette smoking and worsening CKD in patients with diabetes, hypertension, polycystic kidney disease, and post kidney transplant. Nicotine, in addition to its role in the addictive properties of cigarette smoking, has other biological effects via activation of non-neuronal nicotinic acetylcholine receptors (nAChRs). Several nAChR subunits are expressed in the normal kidney and blockade of the α7-nAChR subunit ameliorates the effects of nicotine in animal models of CKD. Nicotine increases the severity of renal injury in animal models including acute kidney injury, diabetes, acute nephritis and subtotal nephrectomy. The renal effects of nicotine are also linked to increased generation of reactive oxygen species and activation of pro-fibrotic pathways. In humans, nicotine induces transitory increases in blood pressure accompanied by reductions in glomerular filtration rate and effective renal plasma flow. In summary, clinical and experimental evidence indicate that nicotine is at least in part responsible for the deleterious effects of cigarette smoking in the progression of CKD. The mechanisms involved are the subject of active investigation and may result in novel strategies to ameliorate the effects of cigarette smoking in CKD.

Inconsistency in albuminuria predictors in type 2 diabetes: a comparison between neural network and conditional logistic regression

Albuminuria is a sensitive marker to predict future cardiovascular events in patients with type 2 diabetes mellitus. However, current studies only use conventional regression models to discover predictors of albuminuria. We have used 2 different statistical models to predict albuminuria in type 2 diabetes mellitus: a multilayer perception neural network and a conditional logistic regression. Neural network models were used to predict the level of albuminuria in patients with type 2 diabetes mellitus, which include a matched case-control study for the population. For each case, we randomly selected 1 control matched by age and body mass index (BMI). The input variables were sex, duration of diabetes, systolic and diastolic blood pressure, glomerular filtration rate, high-density lipoprotein, low-density lipoprotein, triglyceride, high-density lipoprotein/triglyceride ratio, cholesterol, fasting blood sugar, and glycated hemoglobin. Age and BMI were included only in the neural network model. This model included 4 hidden layers and 1 bias. Relative error of predictions was 0.38% in the training group, 0.52% in the testing group, and 1.20% in the holdout group. The most robust predictors of albuminuria were high-density lipoprotein (21%), cholesterol (14.4%), and systolic blood pressure (9.7%). Using the conditional logistic regression model, glomerular filtration rate, time of onset to diabetes, and sex were significant indicators in the onset of albuminuria. Using a neural network model, we show that high-density lipoprotein is the most important factor in predicting albuminuria in type 2 diabetes mellitus. Our neural network model complements the current risk factor models to improve the care of patients with diabetes.

Smoking and type 2 diabetes mellitus

Cigarette smoking is a well-known risk factor in many diseases, including various kinds of cancer and cardiovascular disease. Many studies have also reported the unfavorable effects of smoking for diabetes mellitus. Smoking increases the risk of developing diabetes, and aggravates the micro- and macro-vascular complications of diabetes mellitus. Smoking is associated with insulin resistance, inflammation and dyslipidemia, but the exact mechanisms through which smoking influences diabetes mellitus are not clear. However, smoking cessation is one of the important targets for diabetes control and the prevention diabetic complications.

Gender difference in albuminuria and ischemic heart disease in type 2 diabetes

OBJECTIVE

The value of urinary albumin excretion in the prediction of myocardial ischemia in men and women with type 2 diabetes is not well understood. We questioned whether gender influences the albuminuria-ischemic heart disease relationship in patients with type 2 diabetes.

METHODS

We designed a matched case-control study of 926 patients with albuminuria (cases) and 926 age and body mass index matched patients without albuminuria (controls). Ischemic heart disease was defined as the presence of (1) history of angina pectoris or angina equivalent symptoms and critical care unit admission, (2) myocardial infarction and/or electrocardiographic evidence of Q-wave myocardial infarction, (3) coronary revascularization and/or stenting, (4) positive myocardial single-photon emission computed tomography scan, (5) ischemic ST-segment or T-wave changes, and (6) positive stress testing.

RESULTS

Patients with albuminuria had a lower glomerular filtration rate and a longer diabetes duration than patients without albuminuria. In the group of cases, there were a greater number of men with ischemic heart disease (120 of 370; 32.4%) compared to women (97 of 559; 17.4%) (P<0.001). The odds ratio of having ischemic heart disease according to the presence or absence of albuminuria was 1.25 [95% CI: 1.01-1.56] (P<0.05) in all studied populations, 0.79 [95% CI: 0.51-1.21] (P=0.14) in women, and 2.84 [95% CI: 1.68-4.79] (P<0.001) in men. We showed that diabetes duration, high-density lipoprotein, low-density lipoprotein, and hemoglobin A(1c) influence albuminuria in women, while diabetes duration, fasting blood sugar, and diastolic blood pressure influence albuminuria in men.

CONCLUSIONS

Men with albuminuria are at increased risk of ischemic heart disease compared to women. This may be related to the role of high-density lipoprotein on the albuminuria-gender relationship.

Prevalence of cardiovascular risk factors in patients with type 1 diabetes in end-stage renal disease: changes in the trend from 1999 to 2006

OBJECTIVE

The aim of this study was to describe the prevalence of cardiovascular disease risk factors (CVDRFs) and the degree of control in a Spanish population of patients with type 1 diabetes (DM1) and end-stage renal disease (ESRD) as well as the changes observed in this setting over 8 years.

DESIGN AND METHODS

Patients with DM1 and ESRD were evaluated from 1999 to 2006. Clinical variables, smoking habit, glycosylated hemoglobin (HbA(1c)) and lipids values, and drug treatment were evaluated. The cohort was divided into four biannual groups for analysis. HbA(1c) >7, LDL >100 mg/dl, blood pressure (BP) >140/90 mmHg, and tobacco use were considered as CVDRFs.

RESULTS

A total of 177 patients (65% male) with a mean age of 37.2+/-6.2 years were studied. They had 24.3+/-5.9 years of diabetes evolution. Mean HbA(1c) was 7.9+/-1.5% with 29.6% of patients having values less than 7%. Mean LDL was 109.3+/-40.4 mg/dl and 41.1% were below 100 mg/dl. Over the years these proportions increased significantly (P=.028 and .0015, respectively). Mean systolic and diastolic BP were 142.5+/-22.9 and 82.2+/-14.9 mmHg, respectively, with 53.8% of patients having BP <140/90 mmHg with no changes over the years (P=.11). The proportion of never smokers was 51.5%, reaching 65.5% in the last biannual period (P=.01). In the whole cohort, 89.3% had one or more CVDRFs. There was a statistically significant trend to a reduction in the number of CVDRFs over time (r=-.208, P=.005).

CONCLUSIONS

CVDRFs are highly prevalent in patients with DM1 and ESRD. The control of these CVDRFs is still insufficient; however, there has been a clear improvement in the control over the years.

Continued smoking exacerbates but cessation ameliorates progression of early type 2 diabetic nephropathy

PURPOSE

We tested the hypothesis that continued cigarette smoking exacerbates and its cessation ameliorates progression of the early nephropathy of type 2 diabetes mellitus (DM2) from microalbuminuria to macroalbuminuria.

METHODS

We recruited 91 DM2 subjects with microalbuminuria, 39 nonsmokers and 52 smokers. Smokers underwent smoking cessation intervention with 11 of the 52 smokers quitting, yielding 3 groups: nonsmokers (NS, n = 39), continued smokers (S, n = 41), and quitting smokers (Quit, n = 11), all on angiotensin converting enzyme inhibition (ACEI), treated toward recommended BP and glycemic targets, and followed prospectively for 5 years. Subjects had yearly measurements of estimated glomerular filtration rate (eGFR) and albumin (mg)-to-creatinine (g) ratios (alb/cr) in spot morning urines. Comparison of changes in characteristics was done using analysis of variance, with all pair wise multiple comparison procedure at alpha = 0.05.

RESULTS

Although average urine alb/cr was not different among groups at recruitment, 7 of the 41 S (17%) but none of the 50 NS or Quit progressed to macroalbuminuria (P < 0.003). eGFR decline rate was faster in S (-1.79 +/- 0.35 mL/min/yr) than in NS or Quit (-1.30 +/- 0.43 and -1.54 +/- 0.37 mL/min/yr, respectively, P < 0.001). Multivariate analysis revealed smoking to be the only measured baseline factor that influenced eGFR decline rate (P < 0.041).

CONCLUSION

Smoking exacerbates progression of early to advanced DM2 nephropathy and its cessation is an effective kidney-protective intervention in the early nephropathy of DM2.

Pyelonephritis: radiologic-pathologic review

Urinary tract infections are the most common urologic disease in the United States and annually account for over 7 million office and 1 million emergency department visits. In adults, diagnosis of urinary tract infection is typically based on characteristic clinical features and abnormal laboratory values. Imaging is usually reserved for patients who do not respond to therapy and for those whose clinical presentation is either atypical or potentially life threatening. Urinary tract infection typically originates in the urinary bladder; when it migrates to the kidney or is seeded there hematogenously, a tubulointerstitial inflammatory reaction ensues, involving the renal pelvis and parenchyma. The condition is characterized as pyelonephritis. Complicated and uncomplicated pyelonephritis, xanthogranulomatous pyelonephritis, and tuberculosis are all urinary tract infections for which imaging evaluation adds diagnostic information important for patient care. Computed tomography (CT), when performed before, immediately after, and at delayed intervals from contrast material injection, is the preferred modality for evaluating acute bacterial pyelonephritis. CT is also preferred over conventional radiography and ultrasonography (US) for assessing emphysematous pyelonephritis. Xanthogranulomatous pyelonephritis is a chronic granulomatous process, induced by recurrent bacterial urinary tract infection. Although US is useful in the diagnosis of this condition, CT is the main imaging tool, as it provides highly specific findings and accurate assessment of the extrarenal extent of disease, which is essential for surgical planning. The increasing prevalence of tuberculosis and continued emergence of antibiotic-resistant strains have significance for genitourinary radiologists, as the urinary tract is the most common extrapulmonary site of tuberculosis. Familiarity with the renal manifestations of the disease--pelvoinfundibular strictures, papillary necrosis, cortical low-attenuation masses, scarring, and calcification--will help in the diagnosis, even in the absence of documented pulmonary disease.

Cigarette smoking and incident chronic kidney disease: a systematic review

BACKGROUND

Several studies have examined the role of cigarette smoking in the development of renal disease in human populations. However, there have been no systematic reviews on the evidence linking smoking with incident renal disease.

METHODS

We performed an evidence-based evaluation of peer-reviewed research published during 1966-2005, from a search of five databases, including Ovid MEDLINE and EMBASE.

RESULTS

Of the 28 studies that were reviewed, 11 were excluded from the final analysis due to poor methodological quality (n = 6), no reported risk estimate for the association between smoking and kidney disease (n = 3), inability to find a Japanese translator (n = 1), and duplicate cohort (n = 1). Seventeen studies were included in the final analysis; seven studies found an overall significant association between smoking and incident chronic kidney disease, and three studies found a significantly increased risk of chronic kidney disease in current smokers that was gender and/or dose related. An increased risk of developing chronic kidney disease among smokers was significantly associated with male gender (relative risk 2.4, 95% confidence interval 1.2-4.5), >20 cigarettes smoked/day (odds ratio 1.51, 95% confidence interval 1.06-2.15, and relative risk 2.3, 95% confidence interval 1.2-4.3), and smoking >40 years (odds ratio 1.45, 95% confidence interval 1.00-2.09). A pooled estimate of the relative risk (meta-analysis) was deemed inappropriate due to the heterogeneity in methodologies utilized by the different studies.

CONCLUSIONS

This comprehensive review reveals overall evidence for current cigarette smoking as a risk factor for incident chronic kidney disease. Further investigation is needed to more carefully examine the strength of the association between cigarette smoking and incident kidney disease.

Cigarette smoking is associated with low glomerular filtration rate in male patients with type 2 diabetes

OBJECTIVE

The relationship between cigarette smoking and renal dysfunction in diabetes has predominantly been documented in patients with type 1 diabetes. The aim of the present study was to explore the relationship between cigarette smoking and glomerular filtration rate (GFR) in a large cross-sectional study carried out in male subjects with type 2 diabetes. The role of metabolic syndrome in modulating this relationship was also investigated.

RESEARCH DESIGN AND METHODS

One hundred fifty-eight current smokers and 158 never smokers with type 2 diabetes were consecutively recruited. Low GFR was defined as GFR <60 ml/min per 1.73 m(2).

RESULTS

The proportion of patients affected by low GFR was significantly higher in current smokers (20.9 vs. 12.0%, P = 0.03). The adjusted risk (odds ratio [OR]) of low GFR in current smokers was 2.20 (95% CI 1.14-4.26, P = 0.02) and markedly higher in patients from the first tertile of disease duration (4.27 [1.26-14.40], P = 0.02). When metabolic syndrome was added to the statistical model exploring the relationship between smoking and low GFR, the risk of low GFR showed a small change, although it did not become any more significant (1.84 [0.98-3.45], P = 0.06). Current smokers showed even higher free oxygen radical test unit values (560.0 +/- 91.5 vs. 442.7 +/- 87.2, P < 0.0001).

CONCLUSIONS

In a large population of male patients with type 2 diabetes, the risk of low GFR is markedly enhanced by smoking and is at least partially mediated by metabolic syndrome.

Baseline predictors of renal disease progression in the African American Study of Hypertension and Kidney Disease

Patients with chronic kidney disease have an increased risk for progression to ESRD. The purpose of this study was to examine factors that predict increased risk for adverse renal outcomes. Cox regression was performed to assess the potential of 38 baseline risk factors to predict the clinical renal composite outcome of 50% or 25-ml/min per 1.73 m(2) GFR decline or ESRD among 1094 black patients with hypertensive nephrosclerosis (GFR 20 to 65 ml/min per 1.73 m(2)). Patients were trial participants who had been randomly assigned to one of two BP goals and to one of three antihypertensive regimens and followed for a range of 3 to 6.4 yr. In unadjusted and adjusted analyses, baseline proteinuria was consistently associated with an increased risk for adverse renal outcomes, even at low levels of proteinuria. The relationship of proteinuria with adverse renal outcomes also was evident in analyses that were stratified by level of GFR, which itself was associated with adverse renal outcomes but only at levels <40 ml/min. Other factors that were significantly associated with increased renal events after adjustment for baseline GFR, age, and gender, both with and without adjustment for baseline proteinuria, included serum creatinine, urea nitrogen, and phosphorus. In black patients with hypertensive nephrosclerosis, increased proteinuria, reduced GFR, and elevated levels of serum creatinine, urea nitrogen and phosphorus were directly associated with adverse clinical renal events. These findings identify a subset of this high-risk population that might benefit from even more aggressive treatment.

Therapeutic options for resistant lupus nephritis

OBJECTIVES

To summarize the therapeutic options for proliferative and membranous lupus nephritis that is resistant to conventional treatment.

METHODS

Treatment trials in human lupus nephritis from years 1985 to 2005 that have been published in the English literature were searched by Medline using the keywords "lupus," "nephritis," "glomerulonephritis," "renal," "refractory," "resistant," "recalcitrant," "cyclophosphamide," "mycophenolate," "cyclosporin," "tacrolimus," "leflunomide," "intravenous immunoglobulin," "apheresis," "plasmapheresis," "immunoadsorption," "marrow transplantation," "stem cell transplantation," "immunoablative," "rituximab," and "biologics." Laboratory, histological, and nonrenal lupus studies were excluded.

RESULTS

There is no universal definition of treatment resistance in lupus nephritis. Controlled trials in refractory lupus nephritis are largely unavailable. Open-labeled studies have reported success of newer immunosuppressive drugs, immunomodulatory therapies, and the biological agents such as mycophenolate mofetil (MMF), calcineurin inhibitors, leflunomide, intravenous immunoglobulin, immunoadsorption, and rituximab in the treatment of cyclophosphamide (CYC) resistant proliferative lupus nephritis. More aggressive CYC regimens have been used in lupus nephritis, but at the expense of more toxicities. For membranous lupus nephritis (MLN), a combination of corticosteroids with either azathioprine, chlorambucil, cyclosporin A, MMF, or CYC is initially effective in two-thirds of patients. More aggressive and costly regimens should be reserved for truly refractory disease with persistent nephrotic syndrome or declining renal function. Evidence regarding the efficacy of MMF in refractory MLN is conflicting and controlled trials are necessary to resolve the controversy.

CONCLUSIONS

The treatment of refractory lupus nephritis remains anecdotal. An international consensus in the renal response criteria should be developed and validated so that controlled trials can be performed to compare the efficacy of various treatment modalities.

Cigarette Smoking Enhances Increased Urine Albumin Excretion as a Risk Factor for Glomerular Filtration Rate Decline in Primary Hypertension

BACKGROUND

Subjects with severe compared with mild primary hypertension are at greater risk for decline in glomerular filtration rate (GFR), but additional risk factors are poorly defined.

METHODS

Seventy-five subjects referred for assistance with blood pressure control ("severe") and 150 not-referred hypertensive subjects ("mild") were prospectively followed for 7 years. The primary outcome was the change in calculated GFR during follow-up as predicted by various clinical parameters, including urine albumin excretion measured as urine albumin (mg)-to-creatinine (g) (alb/cr) ratio.

RESULTS

Calculated GFR declined faster (more negative slope) in patients with severe hypertension than in those with mild hypertension (-0.188+/- 0.025 versus -0.120+/- 0.008 mL/min/month; P=0.010), despite similar follow-up systolic blood pressure (133.4+/-1.2 versus 131.9+/-0.8 mm Hg). Severe subjects had higher entry alb/cr (241.3+/- 29.1 versus 11.4+/- 0.5) and a greater proportion of cigarette smokers than mild subjects (56 versus 19%). Regression analysis comparing GFR decline to alb/cr showed that GFR changed minimally for alb/cr up to 200 but declined at a progressively faster rate as alb/cr increased above 200. GFR declined faster (more negative slope) in smokers than in nonsmokers (-0.231+/- 0.023 versus -0.102+/- 0.008 mL/min/month; P<0.001). Cigarette smoking increased the risk for GFR decline in subjects with alb/cr <200 and in those with alb/cr >200, but the effect was much more robust for subjects with alb/cr >200.

CONCLUSIONS

Urine alb/cr >200 increases the risk for subsequent GFR decline in primary hypertension, and this risk is enhanced by cigarette smoking.

Prospective study of lipoprotein(a) as a risk factor for deteriorating renal function in type 2 diabetic patients with overt proteinuria

OBJECTIVE

The effect of lipoprotein(a) [Lp(a)] on the progression of diabetic nephropathy has not been evaluated yet. The aim of this study was to determine whether Lp(a) is an independent risk factor for deteriorating renal function in type 2 diabetic patients with nephropathy.

RESEARCH DESIGN AND METHODS

We conducted this prospective study in type 2 diabetic patients with overt proteinuria. Patients were divided into two groups according to their baseline serum Lp(a) level. Group 1 had Lp(a) levels < or =30 mg/dl (n = 40) and group 2 had Lp(a) levels >30 mg/dl (n = 41). Patients were followed for 2 years. Progression of diabetic nephropathy was defined as a greater than twofold increase of follow-up serum creatinine concentration from the baseline value.

RESULTS

At baseline and during the follow-up, there was no difference in HbA(1c) and lipid profile between groups 1 and 2. However, serum creatinine was significantly higher in group 2 than in group 1 after 1 year (148.3 +/- 78.0 vs. 108.1 +/- 34.9 micromol/l, P = 0.004) and after 2 years (216.9 +/- 144.5 vs. 131.3 +/- 47.3 micromol/l, P = 0.001), although baseline serum creatinine did not differ significantly between groups. In all, 13 of 14 patients with progression of diabetic nephropathy (progressors) were from group 2. Baseline Lp(a) levels were higher in the progressors than in the nonprogressors (62.9 +/- 26.7 vs. 33.5 +/- 27.5 mg/dl, P < 0.001). Multiple logistic regression showed that baseline Lp(a) level was a significant and independent predictor of the progression of diabetic nephropathy.

CONCLUSIONS

Our study demonstrated that Lp(a) is an independent risk factor for the progression of diabetic nephropathy in type 2 diabetic patients with overt proteinuria.

Tratamiento de los pacientes con diabetes mellitus tipo 2 en atención primaria en España

BACKGROUND AND OBJECTIVE

We assess the metabolic control, complications, quality of life related to health (QLRH) and the type and amount of medical resource consumption (MRC) in type 2 diabetic patients (2DMp) followed by primary care physicians (PCP) in Spain.

PATIENTS AND METHOD

We studied 628 2DMp divided in 4 cohorts: 1. Either newly diagnosed 2DMp who required pharmacological treatment or failed to non-pharmacological measures; 2. Patients pharmacologically treated for less than 1 year; 3. Patients with pharmacological treatment for more than 1 year; 4. Patients with impaired fasting glucose (control group).

RESULTS

Eighty percent of the subjects were overweight. At baseline, 27.9, 23.5 and 36.9% of patients from cohorts 1, 2 and 3, respectively, had HbA1C < 8%. After 6 months of follow-up, 14.6, 21.3 and 22.8% of patients from cohorts 1, 2 and 3, respectively, still had "bad control". At baseline, 38.0%, 21.2% and 20.7% of patients from cohorts 1, 2, and 3, respectively, had "bad lipid profile". After 6 months, 57.4%, 54.2% and 45.3% of cohorts 1, 2 and 3, respectively, still had plasma cLDL levels > 130 mg/dl. Complications were more frequent in cohort 3. During the 6-month period, MRC was higher among 2DMp than controls (p < 0.05) and higher among patients from cohort 3 (p < 0.05) compared with all the other patients. More diabetic than control patients and more patients from cohort 3 than patients from cohort 1 and 2 reported that their expected quality of life would be better without diabetes.

CONCLUSIONS

One out of four of diabetic patients studied had HbA1C and lipids higher than the limits suggested by guidelines. Type 2 diabetes is associated with higher MRC and worse QLRH. This situation is worse among long-term diabetic patients.

Progression of nephropathy in type 2 diabetic patients

BACKGROUND

Nephropathy in type 2 diabetes is the single most common cause of end-stage renal disease (ESRD), but the decline in kidney function varies considerably between individuals, and determinants of renal function loss, early in the course of renal disease, have not been clearly identified.

METHODS

In a prospective observational study, we followed 227 (60 female) Caucasian type 2 diabetic patients with nephropathy for 6.5 (range 3 to 17) years from a baseline glomerular filtration rate (GFR) of 83 (SD30) mL/min/1.73m(2) with 7 (range 3 to 22) measurements of GFR ((51)Cr-EDTA) per patient. We evaluated determinants of (1) rate of decline in GFR, (2) risk of doubling in serum creatinine or ESRD, and (3) mortality using potential risk factors at baseline and during follow-up.

RESULTS

The mean (SD) rate of decline in GFR was 5.2 (4.1) mL/min/year. In multivariate regression analysis, higher baseline albuminuria, systolic blood pressure (SBP), hemoglobin A1c, GFR, age, and degree of diabetic retinopathy were significantly associated with increased rate of decline in GFR (R(2) (adj) 0.24). During follow-up, elevated mean albuminuria, SBP, hemoglobin A1c, and lower hemoglobin, heavy smoking, and presence of diabetic retinopathy were significantly associated with increased decline in GFR (R(2) (adj) 0.26). During follow-up, 63 patients had a doubling in serum creatinine or developed ESRD, and 79 patients died, primarily due to cardiovascular disease. In Cox regression analysis, higher baseline albuminuria, hemoglobin A1c, and SBP, together with lower GFR and hemoglobin, were significantly associated with shorter time to doubling of serum creatinine or ESRD. Higher baseline albuminuria, hemoglobin A1c, SBP, and age were significantly associated with increased mortality.

CONCLUSION

Our long-term prospective study of type 2 diabetic patients with nephropathy has revealed several modifiable risk factors of enhanced progression in kidney disease and increased mortality.

Smoking and systemic disease

Cigarette smoking is associated with a number of adverse health effects, including well-established links to cardiopulmonary disease and several cancers. Some of the other important systemic diseases associated with smoking are the subjects of this article, such as diabetes mellitus and insulin resistance and thyroid diseases. Also reviewed here is the negative impact of smoking on male and female infertility, on selected dermatologic conditions, and on gastrointestinal diseases including peptic ulcer and inflammatory bowel diseases.

Intensified treatment of patients with type 2 diabetes mellitus and overt nephropathy

BACKGROUND

Diabetic nephropathy is the single most common cause of chronic renal failure requiring dialysis. Effective treatment exists, but no clinical audit or large trial has reduced the rate of loss of renal function as effectively as in small groups of intensively managed patients.

AIM

To determine the effect of intensive vs. standard medical management on the rate of progression of renal failure in patients with diabetic nephropathy.

DESIGN

Prospective randomized controlled study.

METHODS

Patients with type 2 diabetes and nephropathy were randomly allocated to an intensive group (n = 47) or control group (n = 43). Treatment targets were the same for both groups, but the intensive group were seen as often as required to meet the targets; controls were seen at their normal clinics. The primary end-point was the rate of progression of renal disease in the second year.

RESULTS

The groups were well matched at baseline. During follow-up, the intensive group had lower mean SBP, DBP and cholesterol. Median rate of progression of renal failure in the intensive group fell from 0.44 ml/min/month in the first year to 0.14 ml/min/month in the second year, compared to 0.49 ml/min/month and 0.53 ml/min/month in the control group (p = 0.04 for second year). Patients in the intensive group spent significantly less time in hospital.

DISCUSSION

Intensive treatment slowed progression of renal disease within 2 years in patients with established diabetic nephropathy. Mean creatinine clearance at the start of the trial was 55 ml/min, so assuming that the rates of progression achieved at the end of the second year persisted, onset of dialysis would be delayed by 20 years in the intensive group compared with the control group.

Cigarette Smoking Exacerbates and Its Cessation Ameliorates Renal Injury in Type 2 Diabetes

BACKGROUND

Patients with type 2 diabetes and macroalbuminuria generally experience progressive glomerular filtration rate (GFR) decline despite angiotensin-converting enzyme inhibition (ACEI) and blood pressure (BP) control but this therapy generally stabilizes GFR in those without macroalbuminuria. Cigarette smoking exacerbates GFR decline in patients with type 2 diabetes and macroalbuminuria despite ACEI and BP control; whether this therapy prevents nephropathy progression in nonmacroalbuminuric type 2 diabetic smokers is unknown.

METHODS

We determined the course of urine excretion of indices of renal injury that distinguished patients with type 2 diabetes with and without macroalbuminuria but with normal plasma creatinine who were prospectively followed 6 months while receiving ACEI and BP control. We compared this course in nonsmokers and smokers with normo-, micro-, and macroalbuminuria (n = 157) and in response to smoking cessation in a separate cohort (n = 80) with microalbuminuria.

RESULTS

Urine excretion of transforming growth factor beta-1 (UTGFbetaV) increased in macroalbuminuric but not in nonmacroalbuminuric nonsmokers and UTGFbetaV rate was higher in smokers than nonsmokers within each albuminuria group. In the separate microalbuminuric cohort, the rate of UTGFbetaV change for quitting smokers was not different from nonsmokers (0.093 versus -0.123 ng/g of creatine/week, P = not significant) but that for nonquitting smokers (0.970) was higher than nonsmokers (P = 0.017).

CONCLUSIONS

Patients with type 2 diabetes who are at high risk compared with low risk for nephropathy progression have progressive renal injury as measured by increasing UTGFbetaV. Cigarette smoking exacerbates renal injury in type 2 diabetes despite BP control and ACEI, but its cessation in those with microalbuminuria ameliorates the progressive renal injury caused by continued smoking.

Microalbuminuria and hypertension with focus on type 1 and type 2 diabetes

Microalbuminuria and hypertension with Over the past decade, there has been considerable focus on the concept of microalbuminuria, not only because it predicts renal disease in type 1 and type 2 diabetes, but also because it relates to premature mortality in the diabetic and in the general population. More importantly, intervention at this stage is now possible with the perspective of preserving glomerular filtration rate (GFR) and ameliorating cardiovascular disease and ensuing strong end-points. INITIAL STUDIES: The concept of microalbuminuria was introduced about 20 years ago and since then there has been a multitude of studies and papers on this subject using the original definition, but not always, in the US. Before that time it was suggested, mainly from the US, that diabetic renal disease was an untreatable relentlessly progressive condition.

GENETIC STUDIES

There is an overwhelming number of studies on genetics and diabetes and also covering the genetics of diabetic complications including nephropathy. However, so far the results are extremely disappointing. Patients at risk cannot be identified and genetic analyses are of no value as a guide to treatment. The notion that the development of complications is controlled mainly by a special genetic pattern is increasingly doubtful. In genetic studies, it is rather phenotypic well-accepted risk factors that dominate. STRUCTURAL BASIS OF MICROALBUMINURIA: Patients with microalbuminuria have significant abnormalities in the kidney, including glomeruli. This is quite clear in patients with type 1 diabetes, but is also seen in type 2 diabetes, where on the other hand, other risk factors such as hypertension and dyslipidaemia also seem to be of importance, including loss of autoregulation. Renal biopsies are generally not indicated in the management of diabetic patients. MICROALBUMINURIA AND EARLY MORTALITY: It is quite clear that microalbuminuria predicts early mortality both in type 1 and type 2 diabetes. The association to other risk factors may partly explain this--but this does not account for the whole picture. Endothelial dysfunction as well as inflammatory and arteriosclerotic abnormalities in blood vessels may be a relevant hypothesis that needs to be further explored along with other possibilities. CLINICAL COURSE AND ASSOCIATED ABNORMALITIES: The risk factor for progression in normoalbuminuric patients to microalbuminuria is higher than normal albumin excretion (strongest factor), poor glycaemic control, elevated blood pressure, and to some extent smoking. The clinical course of microalbuminuria is usually progressive, but with the more effective intervention now available we encounter that the so-called natural history (without intervention) is increasingly difficult to study. Microalbuminuria is clearly associated with a number of abnormalities, almost in all organs, but GFR is generally well preserved in spite of more advanced structural lesions. Therefore, microalbuminuria is an important marker for more pronounced diabetic vascular disease in general as well as for nephropathy. Regression to normoalbuminuria only rarely occurs during standard unchanged nonintensive treatment. TREATMENT STRATEGIES: The best possible glycaemic control is important in preventing and ameliorating the course of normo- and micro-albuminuria. Another major treatment strategy, especially in microalbuminuric patients, is antihypertensive treatment including inhibition of the renal angiotensin aldosterone system. Numerous new studies are available, both in type 1 and type 2 diabetes, documenting that not only microalbuminuria but also renal and cardiovascular complications in these patient are also far better controlled by early detection and treatment. Therefore, screening for microalbuminuria should be a strategy in all diabetes management followed by effective intervention as outlined in this paper.

The relationship of cigarette smoking to end-stage renal disease

Cigarette smoking (CS) has been associated with augmented progression of nephropathies responsible for the 4 major causes of end-stage renal disease (ESRD) in the United States. CS has well-described ways by which it causes tissue injury in other organ systems and the mechanisms by which it adversely affects nephropathy progression might be similar. Therefore, exploring the mechanisms for CS-induced nephropathy or progression thereof might yield important insights into the general mechanisms by which some or most nephropathies progress to ESRD. In addition, CS can be discontinued and so is a potentially correctable risk factor for ESRD, a syndrome whose incidence continues to increase. Therefore, the mechanism(s) by which CS induces nephropathy progression is an important area of investigation.

Outcome studies in diabetic nephropathy

Outcome studies in diabetic nephropathy have focused on strategies to prevent progression of diabetic nephropathy, the leading cause of ESRD in the United States. Once diabetics develop overt nephropathy, prognosis is poor. Risk factors for diabetic nephropathy are discussed, and include hyperglycemia, hypertension, angiotensin II, proteinuria, dyslipidemia, smoking, and anemia. Major outcomes as well as outcome studies in diabetic nephropathy for patients with microalbuminuria and macroalbuminuria are reviewed. Furthermore, the role of therapy with angiotensin converting enzyme inhibitors, angiotensin II receptor blockers, calcium channel blockers, and mineralocorticoid receptor antagonists as well as selected combination therapy are discussed. Recommendations for therapy with ace inhibitors and angiotensin II receptor blockers are made based on this evidence.

Cigarette smoking and diabetes

Smokers are insulin resistant, exhibit several aspects of the insulin resistance syndrome, and are at an increased risk for type 2 diabetes. Prospectively, the increased risk for diabetes in smoking men and women is around 50%. Many patients with type 1 and type 2 diabetes mellitus are at risk for micro- and macrovascular complications. Cigarette smoking increases this risk for diabetic nephropathy, retinopathy, and neuropathy, probably via its metabolic effects in combination with increased inflammation and endothelial dysfunction. This association is strongest in type 1 diabetic patients. The increased risk for macrovascular complications, coronary heart disease (CHD), stroke, and peripheral vascular disease, is most pronounced in type 2 diabetic patients. The development of type 2 diabetes is another possible consequence of cigarette smoking, besides the better-known increased risk for cardiovascular disease. In diabetes care, smoking cessation is of utmost importance to facilitate glycemic control and limit the development of diabetic complications.