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

Analysis of the Association between Metabolic Syndrome and Renal Function in Middle-Aged Patients with Diabetes

This study investigated the effects of metabolic syndrome on the estimated glomerular filtration rate in middle-aged participants with diabetes to provide basic data to enable the development of education programs for middle-aged people to prevent diabetic kidney disease. This cross-sectional descriptive study analyzed data obtained in the 2nd year of the 8th Korea National Health and Nutrition Examination Survey in 2020 and enrolled 279 participants aged 40-65 years who were diagnosed with diabetes. Multilevel stratified cluster sampling was used to improve the representativeness of the samples and the accuracy of parameter estimation. The risk factors of metabolic syndrome and the risk of elevated eGFR were analyzed using regression analysis and the correlation between the variables was determined using Pearson's correlation analysis. Middle-aged participants with diabetes whose eGFR was <90 showed a significant difference in their risk for metabolic syndrome based on sex, age, disease duration, and total cholesterol concentrations. Systolic blood pressure and waist circumference in men, and waist circumference and HDL cholesterol level in women were identified as risk factors that contribute to the increasing prevalence of metabolic syndrome.

Should donors who have used marijuana be considered candidates for living kidney donation?

BACKGROUND

The use of marijuana in the USA has been steadily increasing over the last 10 years. This study is the first to investigate the effect of marijuana use by live kidney donors upon outcomes in both donors and recipients.

METHODS

Living kidney donor transplants performed between January 2000 and May 2016 in a single academic institution were retrospectively reviewed. Donor and recipient groups were each divided into two groups by donor marijuana usage. Outcomes in donor and recipient groups were compared using t-test, Chi-square and mixed linear analysis (P < 0.05 considered significant).

RESULTS

This was 294 living renal donor medical records were reviewed including 31 marijuana-using donors (MUD) and 263 non-MUDs (NMUD). It was 230 living kidney recipient records were reviewed including 27 marijuana kidney recipients (MKRs) and 203 non-MKRs (NMKR). There was no difference in donor or recipient perioperative characteristics or postoperative outcomes based upon donor marijuana use (P > 0.05 for all comparisons). There was no difference in renal function between NMUD and MUD groups and no long-term difference in kidney allograft function between NMKR and MKR groups.

CONCLUSIONS

Considering individuals with a history of marijuana use for living kidney donation could increase the donor pool and yield acceptable outcomes.

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.

The rs12917707 polymorphism at the UMOD locus and glomerular filtration rate in individuals with type 2 diabetes: evidence of heterogeneity across two different European populations

Background

UMOD variability has been associated at a genome-wide level of statistical significance with glomerular filtration rate (GFR) in Swedish individuals with type 2 diabetes (T2D; n = 4888). Whether this finding is extensible also to diabetic patients from other populations deserves further study. Our aim was to investigate the relationship between UMOD variability and GFR in patients with T2D from Italy.

Methods

Genotyping of the single nucleotide polymorphism (SNP) rs12917707 at the UMOD locus has been carried out in 3087 individuals from four independent Italian cohorts of patients with T2D by TaqMan allele discrimination.

Results

In none of the four study cohorts was rs12917707 significantly associated with GFR (P > 0.05 for all). Similar results were obtained when the four samples were pooled and analyzed together (β = 0.83, P = 0.19). Such effect was strikingly smaller than that previously reported in Swedish patients (P for heterogeneity = 1.21 × 10-7).

Conclusions

The previously reported strong association between rs12917707 and GFR in diabetic patients from Sweden is not observed in Italian diabetic patients, thus clearly pointing to a heterogeneous effect across the two different samples. This suggests that UMOD is a strong genetic determinant of kidney function in patients with T2D in some, but not all, populations.

Cigarette smoking reduced renal function deterioration in hypertensive patients may be mediated by elevated homocysteine

Elevated homocysteine (HCY) and smoking are both important risk factors for hypertensive patients. However, whether they have crossing effect on renal function deterioration of hypertensive patients and what is the underlying mechanism are unclear. In the present study, 3033 participants diagnosed as essential hypertension with estimated glomerular filtration rate (eGFR)> 30 ml/min/1.73 m² from southern China were enrolled in this cross-sectional study. We collected the demographic and clinical data. In addition, the mediation effects were analyzed. The results showed that, comparing with non-smokers, smokers had significant higher levels of HCY (13.10 (11.20−16.87) vs. 11.00 (8.90−13.40) umol/L, P < 0.001) and lower eGFR (79.71 (66.83−91.05) vs. 82.89 (69.80−95.85) ml/min/1.73m², P < 0.001). HCY levels and smoking were independently associated with decreased eGFR. Meanwhile, eGFR levels were significantly negatively correlated with HCY (P < 0.001), and this correlation might be stronger in current smokers. Current smoker consuming over 20 cigarettes per day would accelerate early renal function deterioration (OR = 1.859, P = 0.019). The mediation effects analysis further showed that the association between smoking and renal function deterioration was mediated by HCY. And elevated HCY was accounted for 56.94% of the estimated causal effect of smoking on renal function deterioration in hypertensive patients. Our findings indicated that cigarette smoking was associated with renal function deterioration in hypertensive patients, and the association between cigarette smoking and renal function deterioration was probably mediated by elevated HCY. Therefore, HCY-lowering therapy may be beneficial for renal function deterioration in hypertensive smoking patients.

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.

Renoprotective effect of curcumin against the combined oxidative stress of diabetes and nicotine in rats

The progression of diabetic nephropathy (DN) is accelerated by smoking. The current study investigated the ability of curcumin to protect the kidneys against damage from oxidative stress induced by diabetes mellitus (DM) and nicotine (NC). A total of 24 male Wistar rats were divided into four groups of six rats each. DM was induced by a single intraperitoneal injection of streptozotocin 60 mg/kg body weight. DM rats were treated with or without NC in the absence or presence of curcumin for 8 weeks. As compared with the controls, DM rats exhibited reduced serum levels of high density lipoprotein, superoxide dismutase and glutathione peroxidase, and decreased renal mRNA expression levels of synaptopodin, connexin 43 and erythropoietin (EPO), which were further suppressed by NC and restored to normal levels by curcumin treatment. Additionally, DM rats exhibited increases in their lipid profiles (cholesterol, triacylglycerol and phospholipids), oxidative markers (malondialdehyde, γ-glutamyltranspeptidase and nitric oxide), kidney function markers (urea and creatinine) and the mRNA expression levels of vimentin, desmin, SREBP-1, iNOS and TGF-β1. These effects were further enhanced by NC, but counteracted by curcumin treatment. Kidneys from DM rats displayed glomerular hypertrophy, sclerosis and tubulo-interstitial changes represented by tubular lipid deposition, interstitial mononuclear cell infiltration and fibroplasia. Pancreatic islets exhibited cellular vacuolation, morphological irregularity and damaged or reduced in size β-cells. These renal and pancreatic changes became more severe following NC treatment and were ameliorated by curcumin. Therefore, NC-induced DN progression may predominantly operate by increasing oxidative stress, reducing the levels of antioxidants, suppressing EPO levels, and causing perturbations to gap junction and podocyte structure. Curcumin may ameliorate the damaging effects of DM and NC on the kidney through normalization of the mRNA expression levels of several genes important in the progression of DN.

Oxidative stress in patients with type 1 diabetes mellitus: is it affected by a single bout of prolonged exercise?

Presently, no clear-cut guidelines are available to suggest the more appropriate physical activity for patients with type 1 diabetes mellitus due to paucity of experimental data obtained under patients' usual life conditions. Accordingly, we explored the oxidative stress levels associated with a prolonged moderate intensity, but fatiguing, exercise performed under usual therapy in patients with type 1 diabetes mellitus and matched healthy controls. Eight patients (4 men, 4 women; 49±11 years; Body Mass Index 25.0±3.2 kg·m⁻²; HbA_1c 57±10 mmol·mol⁻¹) and 14 controls (8 men, 6 women; 47±11 years; Body Mass Index 24.3±3.3 kg·m⁻²) performed a 3-h walk at 30% of their heart rate reserve. Venous blood samples were obtained before and at the end of the exercise for clinical chemistry analysis and antioxidant capacity. Capillary blood samples were taken at the start and thereafter every 30 min to determine lipid peroxidation. Patients showed higher oxidative stress values as compared to controls (95.9±9.7 vs. 74.1±12.2 mg·L⁻¹ H₂O₂; p<0.001). In both groups, oxidative stress remained constant throughout the exercise (p = NS), while oxidative defence increased significantly at the end of exercise (p<0.02) from 1.16±0.13 to 1.19±0.10 mmol·L⁻¹ Trolox in patients and from 1.09±0.21 to 1.22±0.14 mmol·L⁻¹ Trolox in controls, without any significant difference between the two groups. Oxidative stress was positively correlated to HbA_1c (p<0.005) and negatively related with uric acid (p<0.005). In conclusion, we were the first to evaluate the oxidative stress in patients with type 1 diabetes exercising under their usual life conditions (i.e. usual therapy and diet). Specifically, we found that the oxidative stress was not exacerbated due to a single bout of prolonged moderate intensity aerobic exercise, a condition simulating several outdoor leisure time physical activities. Oxidative defence increased in both patients and controls, suggesting beneficial effects of prolonged aerobic fatiguing exercise.

Rate of decline of kidney function in patients with type 2 diabetes mellitus and the associated factors: a 10-year retrospective cohort study

This study examines the rate of decline of estimated glomerular filtration rate (eGFR) over a 10-year period and the associated risk factors in type 2 diabetes mellitus (T2DM) patients. Medical records of T2DM patients were randomly selected. The rate of fall in eGFR (simplified modification of diet in renal disease formula) was used as a measure of decline. Univariate and multivariate analysis were performed to determine the factors associated with decline of kidney function. A total of 504 patients were selected. Mean age was 57.8 ± 9 years; 65.3% were females. The mean decline rate of eGFR was 0.89 ± 2.16 mL/min/1.73 m(2)/y. Baseline proteinuria, glycosylated hemoglobin level, duration of T2DM, and Malay race were associated with faster decline in eGFR. The expected greater deterioration in kidney function in this cohort was not seen. Treatment of proteinuria and glycemia should be optimized early to retard the decline in kidney function in patients with T2DM.

High burden and unmet patient needs in chronic kidney disease

Chronic kidney disease (CKD) is a complex debilitating condition affecting more than 70 million people worldwide. With the increased prevalence in risk factors such as diabetes, hypertension, and cardiovascular disease in an aging population, CKD prevalence is also expected to increase. Increased awareness and understanding of the overall CKD burden by health care teams (patients, clinicians, and payers) is warranted so that overall care and treatment management may improve. This review of the burden of CKD summarizes available evidence of the clinical, humanistic, and economic burden of CKD and the current unmet need for new treatments and serves as a resource on the overall burden. Across countries, CKD prevalence varies considerably and is dependent upon patient characteristics. The prevalence of risk factors including diabetes, hypertension, cardiovascular disease, and congestive heart failure is noticeably higher in patients with lower estimated glomerular filtration rates (eGFRs) and results in highly complex CKD patient populations. As CKD severity worsens, there is a subsequent decline in patient health-related quality of life and an increased use of health care resources as well as burgeoning costs. With current treatment, nearly half of patients progress to unfavorable renal and cardiovascular outcomes. Although curative treatment that will arrest kidney deterioration is desired, innovative agents under investigation for CKD to slow kidney deterioration, such as atrasentan, bardoxolone methyl, and spherical carbon adsorbent, may offer patients healthier and more productive lives.

PPARγ2 P12A polymorphism and albuminuria in patients with type 2 diabetes: a meta-analysis of case-control studies

BACKGROUND

Insulin resistance has a role in diabetic nephropathy. The A12 variant of the PPARγ2 P121A polymorphism has been firmly associated with reduced risk of insulin resistance, while its role on the risk of albuminuria in patients with type 2 diabetes is uncertain. This study investigated whether the PPARγ2 P12A polymorphism modulates the risk of albuminuria in these patients.

METHODS

We tested the association between the A12 variant and albuminuria in three new case-control studies in diabetic patients from Italy (n = 841, n = 623 and n = 714 patients, respectively) and then performed a meta-analysis of all studies available to date. The nine studies we meta-analysed (six previously published and three presented here) comprised a total of 2376 cases and 4188 controls.

RESULTS

In none of the three new studies was a significant association observed with odds ratio (OR) [95% confidence intervals (95% CI)] being 1.115, 0.799 and 0.849 (P = 0.603, 0.358 and 0.518, respectively). At meta-analysis, the overall OR (95% CI) for association between A12 and albuminuria was 0.694 (0.528-0.912). A significant heterogeneity of the genetic effect was observed (P = 0.026), which was totally explained by the different method of urine collection and albuminuria definition utilized across the studies. In fact, most of the effect was observed in the four studies determining albumin excretion rate rather than in those using albumin concentration in a single spot (OR, 95% CI: 0.529, 0.397-0.706, P = 0.0000164 and 0.919, 0.733-1.153, P = 0.47, respectively).

CONCLUSION

The present study shows that the PPARγ2 Ala12 variant is significantly associated with a reduced risk of albuminuria among patients with type 2 diabetes.

Cigarette smoking and proteinuria in Taiwanese men with Type 2 diabetes mellitus

AIMS

Cigarette smoking is a well-known risk factor associated with diabetic nephropathy. The objective of this study was to further investigate the dose-response effect of tobacco exposure on proteinuria in males with Type 2 diabetes.

METHODS

Five hundred and nine males with Type 2 diabetes were selected from a cohort participating in a glucose control study in Taiwan. Pack-years of cigarette smoking were calculated to define tobacco exposure. Proteinuria was identified if albumin-to-creatinine ratio was > or = 30 mg/g in at least two of three consecutive urine tests. Logistic regression and trend tests were used to delineate the association between smoking status and proteinuria.

RESULTS

Compared with non-smokers, those who had smoked 15-30 or more than 30 pack-years were respectively 2.78 (95% CI 1.34-5.76, P < 0.01) and 3.20 (95% CI 1.74-5.86, P < 0.001) times more likely to develop proteinuria. The dose-response effect of tobacco exposure on the development of proteinuria is highly significant in all subjects (P = 0.001) and in subgroups with relatively short duration of diabetes mellitus (P < 0.001), good blood pressure control (P = 0.001) and those of young age (P = 0.007).

CONCLUSIONS

The current study shows a clear dose-response effect of cigarette smoking on development of proteinuria in male Type 2 diabetic patients. These findings reinforce the urgent need to encourage diabetic patients to stop smoking regardless of age, duration of diabetes mellitus or status of blood pressure control.

Measurement of the intrarenal arterial resistance index for the identification and prediction of diabetic nephropathy

BACKGROUND AND AIMS

High intrarenal resistance index (RI) predicts renal function in several conditions; its use in the prediction of diabetic nephropathy (DN) is little explored. We aimed (1) to compare RI in diabetic and non diabetic hypertensive patients, and (2) to evaluate whether high RI is associated with clinical signs of DN and its progression over time.

DESIGN

observational, prospective.

PARTICIPANTS

92 type 2 diabetic patients and 37 non-diabetic controls aged 40-70, with hypertension and normal renal function. We measured ultrasound RI and, among others, creatinine, estimated glomerular filtration rate and urinary albumin excretion rate (AER) at baseline and after 4.5 years follow-up. Progression of albuminuric state (i.e., transition from baseline normo-microalbuminuria to follow-up micro-macroalbuminuria) was evaluated. RI was significantly higher in diabetic than non-diabetic participants (0.69+/-0.05 vs 0.59+/-0.05, p<0.001). Diabetic patients with RI>or=0.73, i.e., above the 80th percentile of the RI distribution, had significantly higher baseline AER and a more frequent progression of the albuminuric state compared to patients with RI<0.73 (27.7microg/mg [12.1-235.4] vs 15.1microg/mg [8.6-33.4]; 52.9% vs 9.5%, respectively). AER increased significantly from baseline to follow-up in patients with RI>or=0.73 (from 27.7microg/mg [12.1-235.4] to 265.0microg/mg [23.8-1018.1], p<0.01), but not in those with RI<0.73 (from 15.1microg/mg [8.6-33.4] to 16.1microg/mg [10.7-67.2], ns). OR for progression of albuminuric state, adjusted for established predictors of DN, including baseline AER, was 5.01 (1.4-17.7, 95% CI) for patients with RI>or=0.73 vs <0.73. Findings were confirmed in patients with normoalbuminuria at baseline.

CONCLUSIONS

In diabetic patients, high RI (>or=0.73) is associated with features of DN and its progression over time, independent of albuminuria.

Socioeconomic inequalities in diabetes mellitus across Europe at the beginning of the 21st century

AIMS/HYPOTHESIS

The aim of this study was to determine and quantify socioeconomic position (SEP) inequalities in diabetes mellitus in different areas of Europe, at the turn of the century, for men and women.

METHODS

We analysed data from ten representative national health surveys and 13 mortality registers. For national health surveys the dependent variable was the presence of diabetes by self-report and for mortality registers it was death from diabetes. Educational level (SEP), age and sex were independent variables, and age-adjusted prevalence ratios (PRs) and risk ratios (RRs) were calculated.

RESULTS

In the overall study population, low SEP was related to a higher prevalence of diabetes, for example men who attained a level of education equivalent to lower secondary school or less had a PR of 1.6 (95% CI 1.4-1.9) compared with those who attained tertiary level education, whereas the corresponding value in women was 2.2 (95% CI 1.9-2.7). Moreover, in all countries, having a disadvantaged SEP is related to a higher rate of mortality from diabetes and a linear relationship is observed. Eastern European countries have higher relative inequalities in mortality by SEP. According to our data, the RR of dying from diabetes for women with low a SEP is 3.4 (95% CI 2.6-4.6), while in men it is 2.0 (95% CI 1.7-2.4).

CONCLUSIONS/INTERPRETATION

In Europe, educational attainment and diabetes are inversely related, in terms of both morbidity and mortality rates. This underlines the importance of targeting interventions towards low SEP groups. Access and use of healthcare services by people with diabetes also need to be improved.

Mortality risks for all causes and cardiovascular diseases and reduced GFR in a middle-aged working population in Taiwan

BACKGROUND

Effects of decreased estimated glomerular filtration rate (eGFR) on cardiovascular disease (CVD) mortality are uncertain in Chinese general populations.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

17,026 adults 50 years and older in Taiwan. A subset of 7,968 had repeated measurements.

PREDICTOR

Decreased eGFR and its progression. eGFR was calculated from serum creatinine level by using the Modification of Diet in Renal Disease Study equation.

OUTCOMES

Mortality from all causes and CVD, including coronary heart disease (CHD) and stroke, from the National Death Registry.

MEASUREMENTS

Hazard ratios (HRs) and Kaplan-Meier survival curves were calculated for participants with a moderate to severe decrease in eGFR (<60 mL/min/1.73 m(2)) compared with those with normal eGFR (> or =90 mL/min/1.73 m(2)). HR of a rapid decrease (> or =20%) in eGFR was also calculated.

RESULTS

Mean age of all participants was 57.2 +/- 5.2 (SD) years. We observed 1,682 deaths in 15 years of follow-up. Participants with a moderate to severe decrease in eGFR had increased HRs for mortality from all causes (1.44; 95% confidence interval [CI], 1.22 to 1.70), CVD (1.90; 95% CI, 1.36 to 2.65), CHD (2.07; 95% CI, 1.26 to 3.41), and stroke (2.16; 95% CI, 1.29 to 3.62) after adjusting for confounders. Decreased eGFR was associated with ischemic stroke, but not hemorrhagic stroke. No significant interaction between decreased eGFR and anemia, diabetes, or smoking was found. There were 660 participants with a 20% or greater decrease in eGFR from baseline during 18 months of follow-up. They had increased HRs for all causes (1.45; 95% CI, 1.13 to 1.86), CVD (2.48; 95% CI, 1.58 to 3.89), CHD (2.14; 95% CI, 1.07 to 4.29), and stroke (2.79; 95% CI, 1.45 to 5.36) compared with those with less than a 20% decrease in eGFR during the same period.

LIMITATIONS

Data for proteinuria were not available. Creatinine assay was not calibrated.

CONCLUSIONS

A moderate to severe or fast decrease in eGFR was associated with all-cause and CVD mortality in this ethnic Chinese cohort.

Obesity and kidney disease

The prevalence of obesity worldwide has increased dramatically. Besides, an approximately two-fold higher rate of increase in mean BMI among the incident ESRD has been reported in the US population from 1995-2002. Chronic kidney disease (CKD) prevalence increases from 2.9% among adults with an ideal BMI to 4.5% among obese adults. The development of CKD is usually the culminating result of the interaction of multiple risk factors. Obesity represents one example of a multitoxicity state and given the background of genetic susceptibility and/or reduced nephron number, overweight may initiate renal remodeling and/or accelerate kidney failure. Obesity may be the number one preventable risk factor for CKD. Weight loss has indeed been shown to improve glomerular hemodynamics and reduce urine albumin excretion. Thus, obese patients with CKD should be counseled on the benefits of weight loss.

Waist circumference is strongly associated with renal resistive index in normoalbuminuric patients with type 2 diabetes

OBJECTIVE

Anthropometric parameters may play a role in modulating the risk of kidney dysfunction. The aim of this study was to evaluate whether anthropometric indices and the metabolic syndrome are associated with alterations of the renal resistive index (RI) in normoalbuminuric type 2 diabetic (T2DM) patients.

METHODS

A sample of 99 consecutively recruited patients with T2DM (76 male and 23 female) was examined. The RI was assessed by duplex Doppler sonography.

RESULTS

In univariate analysis, a significant association between the RI values and age (r = 0.507, p < 0.0001), gender (being higher in women, p = 0.002), systolic blood pressure (r = 0.285, p = 0.011), smoking habit (being lower in current smokers, p = 0.047), estimated glomerular filtration rate (r = -0.435, p < 0.0001), and intima-media thickness of the carotid arteries (r = 0.271, p = 0.020) was observed. As far as anthropometric parameters are concerned, a strong correlation between waist circumference (WC; r = 0.401, p < 0.0001), BMI (r = 0.337, p = 0.003) and RI values was found but only WC maintained a significant correlation after adjusting for several confounders (p = 0.001).

CONCLUSIONS

In normoalbuminuric T2DM patients, the intrarenal hemodynamic abnormalities seem primarily associated with WC.

New predictive equations improve monitoring of kidney function in patients with diabetes

OBJECTIVE

The Cockcroft-Gault and Modification of Diet in Renal Disease (MDRD) equations poorly predict glomerular filtration rate (GFR) decline in diabetic patients. We sought to discover whether new equations based on serum creatinine (the Mayo Clinic Quadratic [MCQ] or reexpressed MDRD equations) or four cystatin C-based equations (glomerular filtration rate estimated via cystatin formula [Cys-eGFR]) were less biased and better predicted GFR changes.

RESEARCH DESIGN AND METHODS

In 124 diabetic patients with a large range of isotopic GFR (iGFR) (56.1 +/- 35.3 ml/min per 1.73 m2 [range 5-164]), we compared the performances of the equations before and after categorization in GFR tertiles. A total of 20 patients had a second determination 2 years later.

RESULTS

The Cockcroft-Gault equation was the least precise. The MDRD equation was the most precise but the most biased according to the Bland-Altman procedure. By contrast with the MDRD and, to a lesser extent, the MCQ, three of the four Cys-eGFRs were not biased. All equations overestimated the low GFRs, whereas only the MDRD and Rule's Cys-eGFR equations underestimated the high GFRs. For the subjects studied twice, iGFR changed by -8.5 +/- 17.9 ml/min per 1.73 m2. GFR changes estimated by the Cockcroft-Gault (-4.5 +/- 6.8) and MDRD (-5.7 +/- 6.2) equations did not correlate with the isotopic changes, whereas new equation-predicted changes did: MCQ: -8.7 +/- 9.4 (r = 0.44, P < 0.05) and all four Cys-eGFRs: -6.2 +/- 7.4 to -7.3 +/- 8.4 (r = 0.60 to 0.62, all P < 0.005), such as 100/cystatin-C (r = 0.61, P < 0.005).

CONCLUSIONS

The new predictive equations better estimate GFR than the Cockcroft-Gault equation. Although the MDRD equation remains the most accurate, it poorly predicts GFR decline, as it overestimates low and underestimates high GFRs. This bias is lesser with the MCQ and Cys-eGFR equations, so they better predict GFR changes.

Normoalbuminuric renal-insufficient diabetic patients: a lower-risk group

OBJECTIVE

About 20% of diabetic patients with chronic kidney disease (CKD) detected from the new American Diabetes Association recommendations (albumin excretion rate >30 mg/24 h or estimated glomerular filtration rate [GFR] <60 ml/min per 1.73 m2) may be normoalbuminuric. Do the characteristics and outcome differ for subjects with and without albuminuria?

RESEARCH DESIGN AND METHODS

A total of 89 patients with diabetes and a modification of diet in renal disease (MDRD) estimated GFR (e-GFR) <60 ml/min per 1.73 m2 underwent a 51Cr-EDTA B-isotopic GFR determination and were followed up for 38 +/- 11 months.

RESULTS

The mean MDRD e-GFR (41.3 +/- 13.1 ml/min per 1.73 m2) did not significantly differ from the i-GFR (45.6 +/- 29.7). Of the subjects, 15 (17%) were normoalbuminuric. Their i-GFR did not differ from the albuminuric rate and from their MDRD e-GFR, although their serum creatinine was lower (122 +/- 27 vs. 160 +/- 71 micromol/l, P < 0.05): 71% would not have been detected by measuring serum creatinine (sCr) alone. They were less affected by diabetic retinopathy, and their HDL cholesterol and hemoglobin were higher (P < 0.05 vs. albuminuric). None of the CKD normoalbuminuric subjects started dialysis (microalbuminuric: 2/36, macroalbuminuric: 10/38) or died (microalbuminuric: 3/36, macroalbuminuric: 7/38) during the follow-up period (log-rank test: P < 0.005 for death or dialysis), and their albumin excretion rate and sCr values were stable after 38 months, whereas the AER increased in the microalbuminuric patients (P < 0.05), and the sCr increased in the macroalbuminuric patients (P < 0.01).

CONCLUSIONS

Although their sCr is usually normal, most of the normoalbuminuric diabetic subjects with CKD according to an MDRD e-GFR below 60 ml/min per 1.73 m2 do really have a GFR below 60 ml/min per 1.73 m2. However, as expected, because of normoalbuminuria and other favorable characteristics, their risk for CKD progression or death is lower.

Diabetes in the Torres Strait Islands of Australia: better clinical systems but significant increase in weight and other risk conditions among adults, 1999-2005

OBJECTIVES

To (i) assess changes in clinical indicators of adults diagnosed with diabetes and (ii) estimate changes in risk factors and incidence of diabetes among adults without diabetes living in the Torres Strait and Northern Peninsula Area Health Service District in Queensland from 1999 to 2005.

DESIGN AND PARTICIPANTS

(i) Annual audit of clinical records of Torres Strait Islander adults on diabetes registers in 21 primary care clinics, and (ii) a 5-year follow up of a community cohort of 207 Torres Strait Islander adults without diabetes who participated in the Well Person's Health Check in 2000-01 and 2005-06.

MAIN OUTCOME MEASURES

Weight, height, waist circumference, fasting blood sugar (those without diabetes) and glycated haemoglobin (HbA1c; those with diabetes) levels, blood pressure (BP), fasting triglyceride and high-density lipoprotein cholesterol levels, urinary albumin-to-creatinine ratio and smoking status.

RESULTS

The number of adults included on the diabetes register increased from 555 in 1999 to 1024 in 2005. The mean age of patients diagnosed with diabetes decreased from 53.3 to 51.5 years, and their mean weight increased from 86.8 kg to 95.6 kg. Mean HbA1c level remained unchanged at about 9%, but the proportion with HbA1c level < 7% increased from 18.4% to 26.1%, and the proportion prescribed insulin increased from 14% in 2002 to 22% in 2005. The proportion with BP < 140/90 mmHg increased from 40.3% in 1999 to 66.8% in 2005. In the sample of 207 adults without diabetes, from 2000 to 2006, there was a weight gain of about 1 kg per person per year, and an annual increase in waist circumference of 0.8 cm in men and 1.2 cm in women. Crude incidence of diabetes was 29 (95% CI, 19-41) per 1000 person-years. There was a significant increase in diastolic blood pressure and fasting blood sugar levels, and no change in smoking habits.

CONCLUSIONS

Clinical care of adults with diabetes has improved and more people with diabetes are being diagnosed. However, weight gain and high rates of glycaemia remain a challenge and will result in a large burden of complications, including renal failure. Incidence data from this sample extrapolate to 120 (95% CI, 103-147) new cases of diabetes in the District each year. Urgent action to improve nutrition, decrease smoking and increase physical activity is required to improve metabolic fitness in younger people.