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

Dietary and lifestyle oxidative balance score was negatively associated with the risk of diabetic kidney disease: NHANES 2005-2020

AIMS

There is a potential association between oxidative stress and the development of diabetic kidney disease (DKD). The Oxidative Balance Score (OBS), derived from dietary and lifestyle factors, acts as a comprehensive marker of oxidative stress. Research examining the relationship between OBS and DKD is scarce. This study aims to evaluate the association between OBS and the risk of DKD among U.S. adults.

METHODS

This study enrolled 6,725 eligible participants from the U.S. population through the National Health and Nutrition Examination Survey (2005-2020). Patients with DKD were defined as those with diabetes who had a urinary albumin-to-creatinine ratio ≥ 30 mg/g and/or an estimated glomerular filtration rate < 60 mL/min/1.73 m². The OBS consists of 20 composite scores derived from dietary and lifestyle factors. To assess the potential relationship between OBS and DKD, weighted logistic regression and restricted cubic spline statistical approaches were employed.

RESULTS

The risk of DKD was inversely correlated with OBS, dietary OBS, and lifestyle OBS (p < 0.05). Compared to the lowest quartile of OBS, the adjusted odds ratios (OR) for OBS, lifestyle OBS and dietary OBS, and DKD in the highest quartile were 0.58 (95% CI: 0.48-0.70), 0.64 (95% CI: 0.51-0.81), and 0.57 (95% CI: 0.46-0.70), respectively. A substantial nonlinear relationship between lifestyle OBS and DKD was identified using the RCS curve (p for nonlinearity = 0.0081), which appeared as an inverted 'L' shape. Using the two-piecewise logistic regression model, a turning point in lifestyle OBS was identified at a score of 3 (p < 0.001).

CONCLUSIONS

Among the American population, OBS and DKD are significantly negatively correlated, suggesting that maintaining a higher OBS may reduce the risk of developing DKD.

Smoking and diabetes

Smoking increases insulin resistance via multiple mechanisms but is a poorly understood risk factor for onset of type-2 diabetes. It is also associated with impaired beta-cell function in humans, but again the mechanisms are poorly understood. Mechanistic studies of the impact of smoking on carbohydrate metabolism mainly evaluated nicotine as the causal agent, and more rarely other tobacco constituents, making it impossible to conclude that the risk of diabetes is linked to the effects of nicotine alone. Active smoking also has negative impact on glycemic control in both type-1 and type-2 diabetic patients. It increases the risk of all-cause mortality and worsens the chronic complications of diabetes. Impact on microangiopathic complications in type-2 diabetic patients, however, is more controversial. Data on pharmacological and behavioral strategies for smoking cessation used in the general population are more sparse in diabetic patients, despite opportunities with recent therapeutic trials involving varenicline and GLP-1 analogues. It is essential for diabetic patients to stop smoking, and diabetologists must get involved in smoking cessation as they have done for many years in therapeutic education, which can easily include measures to help patients stop smoking.

Influence of quitting smoking on diabetes-related complications: A scoping review with a systematic search strategy

INTRODUCTION

Smoking in people with diabetes markedly elevates their risk of developing complications and increases the likelihood of cardiovascular mortality. This review is the first to specifically provide evidence-based analysis about the influence of quitting smoking on diabetes-related complications in people with type 2 diabetes.

METHOD

The present review was carried out according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Extension for Scoping Reviews. All human clinical studies assessing the effects of stopping smoking cessation on diabetes-related complications were included. PubMed and Embase were screened until January 2024. References of primary studies and principal peer-reviewed scientific journals in the field were manually screened.

RESULTS

We identified a total of 1023 studies. Only 26 met the criteria for eligibility. In general quitting smoking is associated with decreased risks of myocardial infarction and ischemic stroke. Regarding microvascular complications, the strongest evidence for the beneficial effects of smoking cessation is observed in diabetic nephropathy. However, the relationship between smoking cessation and retinopathy, neuropathy, diabetic foot complications and diabetic-related erectile dysfunction, is poorly investigated.

CONCLUSION

Quitting smoking offers significant advantages in managing diabetes-related complications, significantly lowering the risks of myocardial infarction, ischemic stroke, and diabetic nephropathy. This underscores the importance of cessation. Providing evidence-based information on the benefits of stopping smoking for people with type 2 diabetes who smoke, can bolster smoking cessation efforts in the context of diabetes management.

Tobacco smoking and diabetes. A comparative survey among diabetologists and smoking cessation specialists

AIMS

Because tobacco smoking is a major risk factor of mortality in diabetes and guidelines suggest evaluating smoking behavior among individuals with diabetes and helping smokers quit, we aimed to assess knowledge about the tobacco smoking - diabetes relationship among diabetologists and smoking cessation specialists (SCS).

METHODS

An online cross sectional survey was conceived by the Working Group on Smoking and Diabetes, France. The questionnaire was tested by the members of the Working Group and deemed to be completed in less than 5 min. Only questions receiving the highest number of approval ratings were kept for the survey. The questionnaire was sent to all members of the French Language Society of Diabetes (Société Francophone du Diabète, SFD), N = 969 and the French Language Society on Tobacco (Société Francophone de Tabacologie, SFT), N = 307. The mailing lists of members were obtained with the previous agreement of the societies' board.

RESULTS

225 diabetologists and 97 SCS (response rate 23.2% and 31.5%, respectively) completed the questionnaire. Over 90% of the diabetologists reported recording smoking status of their patients. Although diabetologists were aware that smoking increases all-cause mortality of individuals with diabetes, only 29.3% were aware that smoking is a risk factor for type 2 diabetes (76.3% among SCS), for poor glycemic control: 32.9% (86.6% among SCS). Significantly less diabetologists (64%) than SCS (76.3%) were aware of smoking being a risk factor for microangiopathy. More diabetologists considered that smoking cessation is more important than optimizing glycemic control among individuals with type 2 (69.3%) than among those with type 1 diabetes (47.1%). Few diabetologists (11.1%) and SCS (14.4%) reported to be trained for smoking cessation among persons with diabetes.

CONCLUSION

Specific knowledge about the negative tobacco smoking - diabetes association seems to be insufficient among French diabetologists. Diabetologists but also other health care professionals should be trained to help individuals with diabetes who smoke to quit smoking.

Smoking and diabetes interplay: A comprehensive review and joint statement

Evidence shows that smoking increases the risk of pre-diabetes and diabetes in the general population. Among persons with diabetes, smoking has been found to increase the risk of all-cause mortality and aggravate chronic diabetic complications and glycemic control. The current paper, which is a joint position statement by the French-Speaking Society on Tobacco (Société Francophone de Tabacologie) and the French-Speaking Society of Diabetes (Société Francophone du Diabète), summarizes the data available on the association between smoking and diabetes and on the impact of smoking and smoking cessation among individuals with type 1, type 2, and gestational diabetes mellitus. It also provides evidence-based information about the pharmacological and behavioral strategies for smoking cessation in these patients.

The Effect of Smoking Cessation on Body Weight and Other Metabolic Parameters with Focus on People with Type 2 Diabetes Mellitus

Smokers with diabetes mellitus substantially lower their risks of microvascular and macrovascular diabetic complications, in particular cardiovascular disease, by quitting smoking. However, subsequent post-smoking-cessation weight gain may attenuate some of the beneficial effects of smoking cessation and discourage attempts to quit. Weight gain can temporarily exacerbate diabetes and deteriorate glycemic control and metabolic profile. The molecular mechanisms by which quitting smoking leads to weight gain are largely associated with the removal of nicotine's effects on the central nervous system. This review addresses mechanisms of post-smoking-cessation weight gain, by reviewing the effects of nicotine on appetite, food intake, eating behaviour, energy expenditure, fat oxidation and appetite-regulating peptides. We also highlight correlations between post-cessation weight gain and risk of type 2 diabetes, consequences of weight gain in people with type 2 diabetes and the role of pharmacotherapies, which combine treatment of nicotine addiction and promotion of weight control.

Diabetic kidney disease treatment: new perspectives

Diabetic kidney disease (DKD) is the leading cause of chronic kidney disease and end-stage kidney disease worldwide, as the obesity epidemic and the burden of diabetes continue to rise globally. In general, guideline management of patients with DKD recommends lifestyle modifications, blood pressure and glycemic control, and dyslipidemia treatment along with other cardiovascular disease risk reduction measures. The inhibition of the renin-angiotensin system (RAS) using an angiotensin-converting enzyme inhibitor or an angiotensin II receptor blocker remains the foundational therapy for DKD. In type 2 diabetes (T2D), significant advances in therapeutics, including the sodium-glucose cotransporter-2 inhibitors (SGLT2i), the glucagon-like peptide-1 receptor agonists (GLP-1 RA), and the nonsteroidal mineralocorticoid receptor agonist (MRA) finerenone, have dramatically expanded the armamentarium for treating DKD and its cardiovascular complications. Initiating, optimizing, and sustaining evidence-based pharmacological therapy using a therapeutic combination of RAS inhibitor + SGLT2i/GLP-1 RA + nonsteroidal MRA + statin is likely to significantly improve outcomes for T2D with DKD. Research into potential novel therapeutic targets for DKD remains particularly active and brings much anticipation and optimism to this field.

Predictors and determinants of albuminuria in people with prediabetes and diabetes based on smoking status: A cross-sectional study using the UK Biobank data

Background

Smoking is attributed to both micro- and macrovascular complications at any stage of metabolic deregulation including prediabetes. Current global diabetes prevention programmes appear to be glucocentric, and do not fully acknowledge the ramifications of cardiorenal risk factors in smokers and ex-smokers. A more holistic approach is needed to prevent vascular complications in people with prediabetes and diabetes before and after quitting.

Methods

A cross-sectional study was carried out on participants who agreed to take part in the UK Biobank dataset at the time of their first attendances between March 01, 2006, and December 31, 2010. Those who had their urinary albumin concentration (UAC) data available were included, and those who did not have this data, were excluded. A logistic regression model was fitted to explore the relationship between cardiorenal risk factors and albuminuria in people with prediabetes and diabetes, based on smoking status.

Findings

A total of 502,490 participants were included in the UK Biobank dataset. Of them, 30.4% (n=152,896) had their UAC level recorded. Compared with non-smokers, the odds of albuminuria in smokers with prediabetes and diabetes were 1.21 (95% CI 1.05 - 1.39, p=0.009), and 1.26 (95% CI 1.10 - 1.44, p=0.001), respectively. The odds declined after quitting in both groups, but it was not statistically significant (p>0.05). Each unit increase in HbA1c was associated with equivalent increased odds of albuminuria in current and ex-smokers, OR 1.035 (95% CI 1.030 - 1.039, p<0.001), and 1.026 (95% CI 1.023 - 1.028, p <0.001), respectively. Compared to females, male ex-smokers were at 15% increased odds of albuminuria. In ex-smokers, each unit increase in waist circumference was associated with 1% increased risk of albuminuria. Compared with the least deprived quintiles, the odds of albuminuria in the most deprived quintiles, in current and ex-smokers were identical, OR 1.18 (95% CI 1.04-1.324, p=0.010), and 1.19 (95% CI 1.11 - 1.27, p<0.001), respectively.

Interpretation

Male smokers are at a higher risk of albuminuria after smoking cessation. Monitoring waist circumference in quitters may identify those who are at a higher risk of albuminuria. Combining smoking cessation intervention in smokers with prediabetes in the current diabetes prevention programmes may offset post-cessation weight gain and reduce the risk of albuminuria.

Funding

University of Sheffield.

Advancements in nanomedicines for the detection and treatment of diabetic kidney disease

In the diabetic kidneys, morbidities such as accelerated ageing, hypertension and hyperglycaemia create a pro-inflammatory microenvironment characterised by extensive fibrogenesis. Radiological techniques are not yet optimised generating inconsistent and non-reproducible data. The gold standard procedure to assess renal fibrosis is kidney biopsy, followed by histopathological assessment. However, this method is risky, invasive, subjective and examines less than 0.01% of kidney tissue resulting in diagnostic errors. As such, less than 10% of patients undergo kidney biopsy, limiting the accuracy of the current diabetic kidney disease (DKD) staging method. Standard treatments suppress the renin-angiotensin system to control hypertension and use of pharmaceuticals aimed at controlling diabetes have shown promise but can cause hypoglycaemia, diuresis and malnutrition as a result of low caloric intake. New approaches to both diagnosis and treatment are required. Nanoparticles (NPs) are an attractive candidate for managing DKD due to their ability to act as theranostic tools that can carry drugs and enhance image contrast. NP-based point-of-care systems can provide physiological information previously considered unattainable and provide control over the rate and location of drug release. Here we discuss the use of nanotechnology in renal disease, its application to both the treatment and diagnosis of DKD. Finally, we propose a new method of NP-based DKD classification that overcomes the current systems limitations.

Recent advances in drug discovery for diabetic kidney disease

INTRODUCTION

Diabetic kidney disease (DKD) is a leading cause of end-stage renal disease (ESRD), and 40% of patients with diabetes develop DKD. Although some pathophysiological mechanisms and drug targets of DKD have been described, the effectiveness or clinical usefulness of such treatment has not been well validated. Therefore, searching for new targets and potential therapeutic candidates has become an emerging research area.

AREAS COVERED

The pathophysiological mechanisms, new drug targets and potential therapeutic compounds for DKD are addressed in this review.

EXPERT OPINION

Although preclinical and clinical evidence has shown some positive results for controlling DKD progression, treatment regimens have not been well developed to reduce the mortality in patients with DKD globally. Therefore, the discovery of new therapeutic targets and effective target-based drugs to achieve better and safe treatment are urgently required. Preclinical screening and clinical trials for such drugs are needed.

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.

Cigarette smoking, type 2 diabetes mellitus, and glucagon-like peptide-1 receptor agonists as a potential treatment for smokers with diabetes: An integrative review

Tobacco use disorder (TUD), in particular cigarette smoking, contributes significantly to the macro- and micro-vascular complications of type 2 diabetes mellitus (DM). Persons with DM who regularly use tobacco products are twice as likely to experience mortality and negative health outcomes. Despite these risks, TUD remains prevalent in persons with DM. The objective of this integrative review is to summarize the relationship between TUD and DM based on epidemiological and preclinical biological evidence. We conclude with a review of the literature on the glucagon-like peptide-1 (GLP-1) as a potential treatment target for addressing comorbid TUD in smokers with DM.

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.

Update of pathophysiology and management of diabetic kidney disease

Diabetic kidney disease (DKD) is a major cause of morbidity and mortality in patients with diabetes mellitus and the leading cause of end-stage renal disease in the world. The most characteristic marker of DKD is albuminuria, which is associated with renal disease progression and cardiovascular events. Renal hemodynamics changes, oxidative stress, inflammation, hypoxia and overactive renin-angiotensin-aldosterone system (RAAS) are involved in the pathogenesis of DKD, and renal fibrosis plays the key role. Intensified multifactorial interventions, including RAAS blockades, blood pressure and glucose control, and quitting smoking, help to prevent DKD development and progression. In recent years, novel agents are applied for preventing DKD development and progression, including new types of glucose-lowering agents, pentoxifylline, vitamin D analog paricalcitol, pyridoxamine, ruboxistaurin, soludexide, Janus kinase inhibitors and nonsteroidal minerocorticoid receptor antagonists. In this review, recent large studies about DKD are also summarized.

Cigarette smoking and risk of albuminuria in patients with type 2 diabetes: a systematic review and meta-analysis of observational studies

BACKGROUND

The aim of this study was to assess the effects of smoking on albuminuria risk in adults with type 2 diabetes mellitus (T2DM).

METHODS

A literature search was conducted using MEDLINE, EMBASE, and China National Knowledge Infrastructure from the established date to October 2017. Summary relative risks (SRR) and 95% confidence intervals (CI) were computed utilizing a random effect inverse variance method.

RESULTS

This meta-analysis included a total of 19 relevant observational studies (four prospective cohort, seven case-control, and eight cross-sectional studies), reporting 105,031 participants and 23,366 albuminuria events. Compared with never-smokers with T2DM, the SRRs of albuminuria were 1.43 (95% CIs 1.27-1.61) for ever-smokers, 2.61 (95% CIs 1.86-3.64) for current smokers, and 1.86 (95% CIs 1.37-2.52) for former smokers. Considerable heterogeneity was observed among these studies, and study design was a significant modifier for this association. There were significantly elevated risk associations for microalbuminuria (SRRs = 1.24, 95% CIs 1.05-1.46) and for macroalbuminuria (SRRs = 1.65, 95% CIs 1.03-2.66), respectively.

CONCLUSIONS

Our systematic review and meta-analysis indicates that cigarette smoking might be a potential factor for the development of albuminuria in adults with T2DM. Future studies are required to investigate the association between smoking cessation and intensity and incident albuminuria in adults with T2DM.

Smoking and the risk of diabetic nephropathy in patients with type 1 and type 2 diabetes: a meta-analysis of observational studies

Background

Conflicting evidence exists for observational studies on whether tobacco smoking is a risk factor for diabetic nephropathy (DN) in patients with type 1 (T1DM) and type 2 diabetes mellitus (T2DM). In this meta-analysis, we aimed to assess the effects of tobacco smoking on the development of DN.

Materials and Methods

We searched MEDLINE and EMBASE databases from their inception to March 31^st, 2017 for cross-sectional, case-control, and prospective cohort studies. We screened reference lists of retrieved articles. Summary relative risks (SRRs) and 95% confidence intervals (CIs) were calculated using a random-effects model.

Results

A total of nineteen observational studies (1 case-control, 8 cross-sectional and 10 prospective cohort studies) were identified, involving more than 78,000 participants and a total of 17,832 DN cases. Compared with never-smokers, there was an augmented SRR (95% CI) of DN in ever-smokers in patients with T1DM (1.31 [1.06–1.62]; P = 0.006) and T2DM (1.44 [1.24–1.67]; P < 0.001), respectively. In patients with T1DM, the SRR (95% CI) was 1.25 (0.86–1.83) for microalbuminuria only, 1.27 (1.10–1.48) for macroalbuminuria only, and 1.06 (0.97–1.15) for end-stage renal disease (ESRD). In patients with T2DM, the SRR (95% CI) associated with ever smoking was 1.46 (0.94–2.26) for microalbuminuria only, 1.72 (1.04–2.84) for macroalbuminuria only, and 1.10 (0.36–3.33) for ESRD.

Conclusions

Our meta-analysis suggests evidence for cigarette smoking as an independent risk factor for the development of DN in patients with both T1DM and T2DM.

Cigarette Smoking Attenuates Kidney Protection by Angiotensin-Converting Enzyme Inhibition in Nondiabetic Chronic Kidney Disease

BACKGROUND

Cigarette smoking exacerbates the estimated glomerular filtration rate (eGFR) decline in nondiabetic chronic kidney disease (CKD) despite the kidney protection that is achieved by angiotensin converting enzyme inhibition (ACEI). Whether smoking cessation restores ACEI-related kidney protection is not known.

METHODS

This 5-year, prospective, prevention trial recruited 108 smokers and 108 nonsmokers with stage-2 nondiabetic CKD with primary hypertension and urine albumin-to-creatinine ratio (Ualb) >200 mg/g. All smokers underwent smoking cessation intervention programs. Blood pressure was reduced in all participants toward achieving a goal of <130 mm Hg with regimens including ACEI. The primary outcome was eGFR change, and secondary outcomes included Ualb and urine levels of angiotensinogen (UATG), a surrogate for kidney angiotensin II (AII) levels, and isoprostane 8-isoprostaglandin F2α (U8-iso), an indicator of oxidative stress.

RESULTS

One-year Ualb was lower than baseline in nonsmokers but not in either smoking group, supporting greater ACEI-related kidney protection in nonsmokers than smokers. Higher Ualb at 1 year in continued smokers was associated with higher UATG and higher U8-iso, consistent with smoking-induced AII and increased oxidative stress contributing to less ACEI-related kidney protection in smokers. Baseline eGFR was not different among groups (p = 0.92), but 5-year eGFR was higher in quitters than in continued smokers (62.0 ± 5.4 vs. 52.9 ± 5.6 mL/min/1.73 m2, p < 0.001); this value was lower in quitters than in nonsmokers (64.7 ± 5.6 mL/min/1.73 m2, p = 0.02).

CONCLUSIONS

Smoking cessation compared with continued smoking ameliorates eGFR decline in nondiabetic CKD treated with ACEI, possibly by restoring kidney-protective effects of ACEI through reductions in kidney AII and oxidative stress.

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.

Smoking has no impact on survival and it is not associated with ACE gene I/D polymorphism in hemodialysis patients

INTRODUCTION

The relationship between smoking and mortality in patients on hemodialysis is controversial. Earlier studies showed that the insertion/deletion (I/D) polymorphism of the ACE gene might have an effect on mortality. The aim of this study was to test the impact of smoking on survival and whether this association was influenced by ACE gene I/D polymorphism in patients on maintenance hemodialysis.

PARTICIPANTS AND METHODS

In this prospective, multicenter cohort study we analyzed 709 prevalent patients on maintenance hemodialysis. Patients were allocated into groups based on their smoking habit. Outcome data were collected during the 144-month follow-up period. Outcomes of current smokers and lifelong non-smokers were compared. In order to control for interactions between predictor variables, we also identified 160 matched pairs for further sub-analysis.

RESULTS

The vast majority of patients (67%) were non-smokers, followed by current smokers (22.2%) and ex-smokers (9.8%). Smoking had no impact on survival in the matched pair analysis ( p = 0.99). After adjustment for ACE I/D polymorphism and other co-variates, smoking had no effect on survival.

CONCLUSION

Our data suggest that smoking has no impact on survival; neither is it associated with ACE gene I/D polymorphism in hemodialysis patients.

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.

The Prevalence of Renal Failure. Results from the German Health Interview and Examination Survey for Adults, 2008-2011 (DEGS1)

BACKGROUND

The prevalence of non-end stage renal failure among adults in Germany is unknown. Accurate figures would enable us to estimate the overall need for kidney replacement therapies and the unexploited potential for disease prevention. Renal failure is also an important cardiovascular risk factor. Until now, American prevalence figures have often been applied to Germany despite dissimilarities between the two populations.

METHODS

We analyzed data on renal function from the nationwide German Health Interview and Examination Survey for Adults, 2008-2011 (DEGS1), which was carried out by the Robert Koch Institute. The glomerular filtration rate was estimated (eGFR) from the serum creatinine and cystatin C levels (CKD-EPI formula) and a semiquantitative measure of albuminuria. Relationships between renal failure and its possible determinants were quantified with adjusted prevalence ratios (PR) and 95% confidence intervals (95% CI).

RESULTS

Roughly 2.3% (95% CI: [1.9; 2.6 ]) of persons aged 18-79 had an eGFR below 60 mL/min/1.73 m2. The prevalence rose with age. We extrapolated these figures conservatively to persons aged 80 and above, who were not included in the DEGS1, and arrived at a figure of at least 2 million persons in Germany with renal failure. 11.5% of the population have albuminuria of at least 30 mg/L. Diabetes mellitus (PR = 2.25, 95% CI: [1.59; 3.16]) and arterial hypertension (PR = 3.46, 95% CI: [1.95; 6.12]) are important determinants.

CONCLUSION

This study provides the first representative estimate of the prevalence of renal failure in Germany. The condition is highly dependent on age but less prevalent than previously assumed on the basis of American prevalence figures.

Impact of Lifestyle Modification on Diabetic Kidney Disease

Kidney disease is common in patients with type 1 and type 2 diabetes mellitus and is associated with adverse health outcomes, including progression to end-stage renal disease. In the general population, adherence to a healthy lifestyle is known to reduce the risk of cardiovascular events and death. Among individuals with diabetic kidney disease, modifications in lifestyle factors, including diet, physical activity, smoking habits, and body mass index, represent a promising cost-effective therapeutic adjunct to pharmacologic treatment of kidney disease incidence and progression.

Experiences of People with Diabetes by Payer Type: An Analysis of the Roper Diabetes Data Set

INTRODUCTION

The study details the experiences of Medicare, Medicaid and privately insured patients with diabetes in the United States by focusing on how these distinct populations perceive their disease and manage their treatment.

METHODS

A national survey was fielded among a representative sample of 2,307 US adult diagnosed diabetes patients to investigate demographic, lifestyle, treatment, access to information, and socioeconomic status. This was achieved using a combination of telephone-based interviews and internet-based questionnaires administered via KnowledgePanel®, the only large-scale online panel based on a representative random sample of the US population.

RESULTS

Patients with Medicaid-based insurance face significant differences in diagnosis, treatment and intensity of their diabetes as compared to their Medicare and privately insured counterparts. Medicaid patients develop diabetes at an earlier age with an increased level of severity, and face significant socioeconomic concerns. Medicaid patients also have different health information seeking preferences than their counterparts, impacted by technology use patterns and education preferences. All groups report challenges in paying for their diabetes care, though cost-sharing requirements are relatively low.

CONCLUSIONS

Significant variation in experience between Medicaid, Medicare, and privately insured patients can inform disease management and patient engagement strategies. Payers, clinicians and public health agencies can leverage these findings to design initiatives more effectively and understand how intergroup variability impacts program uptake and disease outcomes.

Present and future in the treatment of diabetic kidney disease

Diabetic kidney disease is the leading cause of end-stage renal disease. Albuminuria is recognized as the most important prognostic factor for chronic kidney disease progression. For this reason, blockade of renin-angiotensin system remains the main recommended strategy, with either angiotensin converting enzyme inhibitors or angiotensin II receptor blockers. However, other antiproteinuric treatments have begun to be studied, such as direct renin inhibitors or aldosterone blockers. Beyond antiproteinuric treatments, other drugs such as pentoxifylline or bardoxolone have yielded conflicting results. Finally, alternative pathogenic pathways are being explored, and emerging therapies including antifibrotic agents, endothelin receptor antagonists, or transcription factors show promising results. The aim of this review is to explain the advances in newer agents to treat diabetic kidney disease, along with the background of the renin-angiotensin system blockade.

Continued smoking abstinence in diabetic patients in primary care: a cluster randomized controlled multicenter study

AIMS

To assess the effectiveness of an intensive smoking cessation intervention based on the transtheoretical model of change (TTM) in diabetic smokers attending primary care.

METHODS

A cluster randomized controlled clinical trial was designed in which the unit of randomization (intervention vs. usual care) was the primary care team. An intensive, individualized intervention using motivational interview and therapies and medications adapted to the patient's stage of change was delivered. The duration of the study was 1 year.

RESULTS

A total of 722 people with diabetes who were smokers (345 in the intervention group and 377 in the control group) completed the study. After 1 year, continued abstinence was recorded in 90 (26.1%) patients in the intervention group and in 67 (17.8%) controls (p=0.007). In patients with smoking abstinence, there was a higher percentage in the precontemplation and contemplation stages at baseline in the intervention group than in controls (21.2% vs. 13.7%, p=0.024). When the precontemplation stage was taken as reference (OR=1.0), preparation/action stage at baseline showed a protective effect, decreasing 3.41 times odds of continuing smoking (OR=0.293 95% CI 0.179-0.479, p<0.001). Contemplation stage at baseline also showed a protective effect, decreasing the odds of continuing smoking (OR=0.518, 95% CI 0.318-0.845, p=0.008).

CONCLUSIONS

An intensive intervention adapted to the individual stage of change delivered in primary care was feasible and effective, with a smoking cessation rate of 26.1% after 1 year.

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.

The effects of GLP-1 analogues, DPP-4 inhibitors and SGLT2 inhibitors on the renal system

Diabetic nephropathy (DN) affects an estimated 20%-40% of patients with type 2 diabetes mellitus (T2DM). Key modifiable risk factors for DN are albuminuria, anaemia, dyslipidaemia, hyperglycaemia and hypertension, together with lifestyle factors, such as smoking and obesity. Early detection and treatment of these risk factors can prevent DN or slow its progression, and may even induce remission in some patients. DN is generally preceded by albuminuria, which frequently remains elevated despite treatment in patients with T2DM. Optimal treatment and prevention of DN may require an early, intensive, multifactorial approach, tailored to simultaneously target all modifiable risk factors. Regular monitoring of renal function, including urinary albumin excretion, creatinine clearance and glomerular filtration rate, is critical for following any disease progression and making treatment adjustments. Dipeptidyl peptidase (DPP)-4 inhibitors and sodium-glucose cotransporter 2 (SGLT2) inhibitors lower blood glucose levels without additional risk of hypoglycaemia, and may also reduce albuminuria. Further investigation of the potential renal benefits of DPP-4 and SGLT2 inhibitors is underway.

Cardiovascular complications of diabetic kidney disease

Diabetic nephropathy is the most common cause of CKD and represents a large and ominous public health problem. Patients with diabetic kidney disease have exceptionally high rates of cardiovascular morbidity and mortality. In fact, the excess mortality among patients with diabetes appears to be largely limited to the subgroup with kidney disease and explained by their high burden of cardiovascular disease. The mechanisms underlying the strong association between diabetic kidney disease and various forms of cardiovascular disease are poorly understood. Traditional risk factors for cardiovascular disease, although prevalent among those with diabetes, do not fully account for the heightened risk observed. Despite their susceptibility to cardiovascular disease, patients with CKD are less likely to receive appropriate risk factor modification than the general population. Moreover, because patients with CKD have commonly been excluded from major cardiovascular trials, the evidence for potential treatments remains limited. The mainstays of treatment for diabetic kidney disease currently include blockade of the renin-angiotensin-aldosterone system and control of hypertension, hyperglycemia, and dyslipidemia. Increased awareness of the vulnerability of this patient population and more timely interventions are likely to improve outcomes while large evidence gaps are filled with newer studies.

Cilostazol effectively attenuates deterioration of albuminuria in patients with type 2 diabetes: a randomized, placebo-controlled trial

Cilostazol is an antiplatelet, antithrombotic agent with anti-inflammatory properties. To date, no clinical study has specifically evaluated the efficacy of cilostazol in patients with diabetic nephropathy (DN). We hypothesized that cilostazol might delay renal deterioration in DN patients at high risk of progression. Between April 2008 and April 2010, we screened 156 consecutive patients aged 35-80 years who were first diagnosed with type 2 diabetes after the age of 30 years. Of these, 90 patients with DN, as defined by morning spot urine microalbuminuria (MAU) >20 mg/L or an albumin-to-creatinine ratio (ACR) >30 μg/mg on at least two consecutive occasions within the prior 3 months, were enrolled into a 52-week randomized, single-blinded, placebo-controlled trial of oral cilostazol 100 mg twice daily or placebo (45 subjects in each group). Morning spot urine samples were collected to determine MAU and ACR. Fasting plasma levels of metabolic, endothelial variables, and inflammatory markers were examined. Following 52 weeks of treatment, urinary MAU and ACR were significantly reduced in the cilostazol group compared with the placebo group (P = 0.024 and P = 0.02, respectively). In regression analyses, changes in monocyte chemotactic protein-1, E-selectin, and soluble vascular cell adhesion molecule-1 (sVCAM-1) were significantly associated with changes in MAU and ACR. Net changes of E-selectin (P < 0.001) and sVCAM-1 (P < 0.05) were independent predictors of change in MAU and ACR, respectively. Our results suggest that cilostazol may effectively attenuate deterioration of albuminuria in patients with type 2 diabetes. This effect is likely mediated by an improvement of adhesion molecules.

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.

Clinical manifestations and natural history of diabetic kidney disease

Renal failure in type 2 diabetes has been termed "a medical catastrophe of worldwide dimension". In 2001, we found in our unit that 49% of incident patients requiring maintenance hemodialysis had diabetes (i.e. 98/million population/year), 6% of whom had type 1 and most (94%) had type 2 diabetes, i.e. more than the than reported frequency in Germany (approximately 35% of incident patients). The frequency is underestimated because hyperglycemia is often lost in the preterminal phase when diabetic patients lose weight and fasting hyperglycemia.

Smoking cessation predicts amelioration of microalbuminuria in newly diagnosed type 2 diabetes mellitus: a 1-year prospective study

The objective of the study was to assess the effect of smoking cessation on microalbuminuria in subjects with newly diagnosed type 2 diabetes mellitus (DM). From 500 smokers newly diagnosed with type 2 DM and microalbuminuria, only 193 (96 men/97 women; age, 56.4 ± 7.8 years) agreed to participate and were educated on smoking cessation, diet, and exercise. Pharmacological interventions were not different among the studied groups. All subjects were contacted by phone monthly with emphasis on smoking cessation. Anthropometric, biochemical parameters and urine specimens were obtained at baseline and at 12-month follow-up. Microalbuminuria was defined as an albumin to creatinine ratio of 30 to 299.9 μg/mg creatinine. Ankle brachial pressure index was determined by ultrasound. A total of 120 (62.2%) subjects quit smoking. Prevalence of microalbuminuria was reduced at 1 year to 72.6% in the subjects who quit smoking and to 22.5% in those who continued smoking (P = .015). Multivariate logistic regression analysis demonstrated that independently associated with the reduction in albumin to creatinine ratio (84.8 vs 28.7 μg/mg creatinine) were amelioration of glycemic control (P < .001), blood pressure (P = .02), dyslipidemia (P = .02), and insulin resistance (P = .05). Smoking cessation also reduced the prevalence of peripheral vascular disease (P = .03) and neuropathy (P = .04). From the pharmacological and lifestyle interventions, smoking cessation had the highest and an independent contribution to the reduction of microalbuminuria (P < .001). Smoking cessation in newly diagnosed type 2 DM patients is associated with amelioration of metabolic parameters, blood pressure, and the reduction of microalbuminuria. Stricter counseling about the importance of quitting smoking upon type 2 DM diagnosis is necessary to protect against the development of diabetic nephropathy and vascular complications.

Recognition, pathogenesis, and treatment of different stages of nephropathy in patients with type 2 diabetes mellitus

Nephropathy is a common microvascular complication among patients with type 2 diabetes mellitus and a major cause of kidney failure. It is characterized by albuminuria (≥ 300 mg/d) and a reduced glomerular filtration rate and is often present at the time of diabetes diagnosis after the kidney has been exposed to chronic hyperglycemia during the prediabetic phase. A low glomerular filtration rate (<60 mL/min/1.73 m(2)) is also an independent risk factor for cardiovascular events and death. Detection of diabetic nephropathy during its initial stages provides the opportunity for early therapeutic interventions to prevent or delay the onset of complications and improve outcomes. An intensive and multifactorial management approach is needed that targets all risk determinants simultaneously. The strategy should comprise lifestyle modifications (smoking cessation, weight loss, increased physical activity, and dietary changes) coupled with therapeutic achievement of blood glucose, blood pressure, and lipid goals that are evidence-based. Prescribing decisions should take into account demographic factors, level of kidney impairment, adverse effects, risk of hypoglycemia, tolerability, and effects on other risk factors and comorbidities. Regular and comprehensive follow-up assessments with appropriate adjustment of the therapeutic regimen to maintain risk factor control is a vital component of care, including referral to specialists, when required.

Essential hypertension and risk of nephropathy: a reappraisal

PURPOSE OF REVIEW

Treating mild-to-moderate essential hypertension in nondiabetic African Americans fails to halt nephropathy progression, whereas hypertension control slows nephropathy progression in European Americans. The pathogenesis of these disparate renal syndromes is reviewed.

RECENT FINDINGS

The nonmuscle myosin heavy chain 9 gene (MYH9) is associated with a spectrum of kidney diseases in African Americans, including idiopathic focal global glomerulosclerosis historically attributed to hypertension, idiopathic focal segmental glomerulosclerosis, and the collapsing variant of focal segmental glomerulosclerosis [HIV-associated nephropathy (HIVAN)]. Risk variants in MYH9 likely contribute to the failure of hypertension control to slow progressive kidney disease in nondiabetic African Americans.

SUMMARY

Early and intensive hypertension control fails to halt progression of 'hypertensive nephropathy' in African Americans. Genetic analyses in patients with essential hypertension and nephropathy attributed to hypertension, focal segmental glomerulosclerosis and HIVAN reveal that MYH9 gene polymorphisms are associated with a spectrum of kidney diseases in this ethnic group. Mild to moderate hypertension may cause nephropathy in European Americans with intrarenal vascular disease improved by the treatment of hypertension, hyperlipidemia and smoking cessation.

The spectrum of MYH9-associated nephropathy

Causes of the excess incidence rates of chronic kidney disease in the African American population have long been under study. Recently, polymorphisms in the nonmuscle myosin heavy chain 9 gene (MYH9) have been associated with nondiabetic kidney diseases in African- and European-derived populations. Risk variants in MYH9 contribute to approximately 70% of nondiabetic forms of ESRD in African Americans and 40 to 45% of all ESRD in this ethnic group, with lesser effects in European Americans. It is clear that MYH9 polymorphisms have a significant impact on the incidence rates of kidney disease in African Americans. This article describes the current spectrum of biopsy-proven MYH9-associated kidney diseases, along with potential effects of MYH9 on ethnic differences in clinical outcome. MYH9 risk variants exhibit the most impressive association with any common complex kidney disease yet identified.