Determinants of albuminuria in people with Type 2 diabetes mellitus

Association between cotinine-verified smoking status and moderately increased albuminuria in the middle-aged and older population in Korea: A nationwide population-based study

Objectives

Although several self-reported questionnaire-based studies have found an association between smoking and moderately increased albuminuria, this result remains controversial. We investigated whether moderately increased albuminuria was associated with smoking status, verified by urinary cotinine (an objective biomarker of tobacco exposure), using population-based, nationally representative data.

Methods

This study included 2059 participants aged ≥ 50 years from the 2014 Korean National Health and Nutrition Examination Survey. Individuals with a urinary cotinine level ≥ 50 ng/mL were identified as cotinine-verified smokers. Moderately increased albuminuria was defined as a urine albumin-to-creatinine ratio ranging between ≥ 30 mg/g and < 300 mg/g. Multivariable logistic regression was used to evaluate the association between cotinine-verified smoking status and moderately increased albuminuria.

Results

Among the study participants, 16.9% were cotinine-verified smokers, 84.8% of whom were men. After adjustment for multiple covariates, cotinine-verified smokers showed a significant positive association with moderately increased albuminuria (adjusted odds ratio: 4.37, 95% confidence interval: 1.63–11.71) compared with cotinine-verified non-smokers. The association between urinary cotinine and moderately increased albuminuria did not differ with age, sex, obesity, or comorbidities (P-value for interaction > 0.05 in all cases).

Conclusion

This large-scale observational study showed that cotinine-verified smoking is associated with moderately increased albuminuria in the Korean middle-aged and older general population, suggesting that smoking must be strictly controlled to reduce the risk of moderately increased albuminuria.

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 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.

The evidence for medical nutrition therapy for type 1 and type 2 diabetes in adults

This article reviews the evidence and nutrition practice recommendations from the American Dietetic Association's nutrition practice guidelines for type 1 and type 2 diabetes in adults. The research literature was reviewed to answer nutrition practice questions and resulted in 29 recommendations. Here, we present the recommendations and provide a comprehensive and systematic review of the evidence associated with their development. Major nutrition therapy factors reviewed are carbohydrate (intake, sucrose, non-nutritive sweeteners, glycemic index, and fiber), protein intake, cardiovascular disease, and weight management. Contributing factors to nutrition therapy reviewed are physical activity and glucose monitoring. Based on individualized nutrition therapy client/patient goals and lifestyle changes the client/patient is willing and able to make, registered dietitians can select appropriate interventions based on key recommendations that include consistency in day-to-day carbohydrate intake, adjusting insulin doses to match carbohydrate intake, substitution of sucrose-containing foods, usual protein intake, cardioprotective nutrition interventions, weight management strategies, regular physical activity, and use of self-monitored blood glucose data. The evidence is strong that medical nutrition therapy provided by registered dietitians is an effective and essential therapy in the management of diabetes.

Treatment of type 2 diabetes mellitus in a primary care setting in Taiwan: comparison with secondary/tertiary care

BACKGROUND

This study investigated the status of diabetes control and management in patients treated in a primary healthcare setting and compared the results with data previously obtained for secondary/tertiary care patients in Taiwan.

METHODS

This study was conducted at 51 primary healthcare stations randomly selected island-wide in Taiwan in 2001. A total of 1302 type 2 diabetes patients who had been followed-up for more than 1 year were included. Blood was collected for centralized HbA1c assay. The remaining data and information were collected by review of medical records and patient interview.

RESULTS

Compared with the results of a previous study on patients treated in a secondary/tertiary care setting, a significantly smaller percentage of primary care patients were receiving insulin therapy. Primary care patients also had a shorter duration of diabetes, a higher HbA1c level, better blood pressure control and a lower prevalence of complications. The proportion of patients achieving optimal control of glycemia and blood pressure was low. Patients aged < 65 years had a significantly shorter duration of diabetes, poorer diabetes control and better blood pressure control than elderly patients aged > or = 65 years. Primary care patients aged > or = 65 years had a significantly higher frequency of stroke than those aged < 65 years. The elderly group of secondary/tertiary care patients had a significantly higher frequency of coronary heart disease and stroke. Duration of diabetes and hypertension were the leading risk factors for complications in diabetes patients treated in both primary and secondary/tertiary care settings.

CONCLUSION

Diabetes control was poorer in primary care than in secondary/tertiary care patients, but control of blood pressure was better in primary care patients. The shorter duration of diabetes and better control of blood pressure in primary care patients and in patients aged < 65 years compared with their elderly counterparts might be related to a lower prevalence of complications.

Risk factors for development of impaired renal function in Type 2 diabetes mellitus patients in primary care

AIMS

To evaluate risk factors for the development of an impaired renal function, defined as a glomerular filtration rate (GFR) by Cockcroft-Gault formula < 50.5 ml/min, in primary care patients with Type 2 diabetes mellitus.

METHODS

A case-control study of Type 2 diabetes mellitus patients with impaired renal function and age, sex and practice matched controls with Type 2 diabetes mellitus without impaired renal function in 10 Dutch family practices performing the Nijmegen Monitoring Project. Main outcome measure was the independent risk factors of impaired renal function.

RESULTS

Eighty-seven individuals with impaired renal function were identified. The point prevalence of impaired renal function in the sample population on 31 March 2001 was 87/873 (10.0%; 95% confidence interval 7.0-15.1%). Of 87 cases, 23 (26.5%; 17.3-30.9%) were found to have impaired renal function at diagnosis. Conditional multiple logistic regression analysis revealed the following independent risk factors for the development of impaired renal function: duration of diabetes > or = 8 years (adjusted odds ratio 5.6 (2.5-12.5); P < 0.001), glomerular filtration rate by Cockcroft-Gault formula 50.5-80.5 ml/min at diagnosis [3.5 (1.5-8.1); P < 0.01] and existing macrovascular complications at diagnosis [2.6 (1.1-6.3); P < 0.01].

CONCLUSION

Duration of diabetes > or = 8 years, mild renal impairment at the time of diagnosis and existing macrovascular complications at the time of diagnosis are independent risk factors for the development of impaired renal function in white patients with Type 2 diabetes mellitus.

Urinary albumin to osmolality ratio predicts 24-hour urine albumin excretion in diabetes mellitus

BACKGROUND

Urinary albumin to creatinine ratio (ACR) in a single urine sample has been proposed to provide an estimate of microalbuminuria by adjusting for variability in urine concentrations. We hypothesized that adjusting the urine albumin concentration of single-void specimens for actual urine osmolality (urinary albumin to osmolality ratio [AOR]) may provide a more accurate estimate of 24-hour urine albumin excretion rates (AERs).

METHODS

Patients with diabetes mellitus (DM; n = 136) had urinary concentrations of albumin, glucose, and creatinine and osmolality measured on single-void samples, and albumin levels, on 24-hour samples. Microalbuminuria is defined as an AER between 30 and 300 mg/d.

RESULTS

Correlation between AOR on single-void samples and AER on 24-hour samples (r = 0.87; P < 0.001) was similar to that between ACR and AER (r = 0.88; P < 0.001). Using a cutoff value of 18.4 mg/kg/mOsm x 10(2) (18.4 mg/mmol x 10(2)) for AOR resulted in a sensitivity and specificity of 82% and 86% in detecting microalbuminuria, respectively. The area under the curve (AUC) for AOR was 0.89. Using a cutoff value of 15.0 mg/g (1.7 mg/mmol) for ACR resulted in a sensitivity and specificity of 85% and 85% in detecting microalbuminuria, respectively. The AUC for ACR was 0.90. The ability of AOR to predict AER was maintained at varying degrees of glycosuria (glucose < 100 mg/dL [<5.5 mmol/L]; r = 0.77; 100 to 750 mg/dL [5.5 to 42 mmol/L]; r = 0.85; and >750 mg/dL [>42 mmol/L]; r = 0.92).

CONCLUSION

Urinary AOR correlates closely with 24-hour microalbuminuria determination, and the correlation is not appreciably affected by glycosuria. Thus, AOR can be used as an alternative test to ACR in the assessment of microalbuminuria in the population with DM.

HRT does not improve urinary albumin excretion in postmenopausal diabetic women

The effect of 6 months combined, continuous hormone replacement therapy (HRT) with conjugated equine oestrogen (0.625 mg) and medroxyprogesterone acetate (2.5 mg) on albumin/creatinine ratio (ACR) was determined in postmenopausal diabetic women in a randomised, controlled study. Mean (interquartile range) change in plasma ACR was not (P=0.96) different in women receiving HRT [2 (-11, 21) mg/g, n=20] compared with those randomised to placebo [2 (-1, 14) mg/g, n=27]. Also, the proportion of women with microalbuminuria did not change (P=0.75) during HRT (baseline, 0.45; end of study, 0.53). Furthermore, several risk factors for microalbuminuria including systolic blood pressure (SBP), fasting blood glucose, glycated haemoglobin (HbA1c) and adiposity did not vary significantly during HRT. These data suggest that 6 months HRT does not reverse microalbuminuria caused by prolonged hyperglycaemia and other risk factors that underlie leakage of albumin into the urine in postmenopausal women with type 2 diabetes.

Protein restriction, glomerular filtration rate and albuminuria in patients with type 2 diabetes mellitus: a randomized trial

OBJECTIVE

Protein restriction delays the progression of non-diabetic and type 1 diabetic renal disorders. This study assessed whether protein restriction delays the onset or early progression of renal disorders in type 2 diabetes.

DESIGN

Randomized controlled trial. Outcomes were albuminuria (mg/24 h) and, as an estimate of the glomerular filtration rate, cimetidine-influenced creatinine clearance.

SETTING

Primary care.

SUBJECTS

Patients with type 2 diabetes and microalbuminuria or at least detectable albuminuria, or a diabetes duration >5 y.

INTERVENTIONS

The experimental group received dietary counselling on protein restriction (n=63); a control group (n=68) received the usual dietary advice. The duration of intervention and follow-up was 28+/-7 months.

RESULTS

After 6 months, protein intake differed only by 0.08 g/kg/day between the study groups. Subsequently, this difference decreased and eventually disappeared. An initial effect of protein restriction on albuminuria in favor of the experimental group was not sustained, and the glomerular filtration rate decreased in the experimental group at a 1.6+/-2.2 ml/min/1.73 m(2) y lower rate than in the control group (P=0.5). Comparison of patients in the experimental group with a decrease in protein intake of at least 0.20 g/kg/day, with controls with no decrease, indicated a similarly small and insignificant effect on glomerular filtration rate.

CONCLUSIONS

It is concluded that, in the longer term prevention or delay of renal damage in patients with type 2 diabetes, protein restriction is neither feasible nor efficacious.

The renal risks of smoking: an update

PURPOSE OF REVIEW

Smoking increases the renal risk both in diabetic and in nondiabetic renal disease. The purpose of the present review is to summarize the current state of knowledge about this important remediable renal risk factor.

RECENT FINDINGS

The deleterious effect of smoking on renal function extends beyond patients with primary or secondary renal disease and patients with a renal transplant, because recent studies document a relation between smoking and loss of filtration rate, even in cardiovascular high-risk populations without primary renal disease such as the elderly, the patient with severe essential hypertension, or the patient with widespread atherosclerosis. Furthermore, recent studies show that in nondiabetic patients without primary renal disease, albuminuria, a potential surrogate marker of glomerular damage, is correlated with smoking. The mechanisms underlying the adverse renal effects of smoking are still incompletely understood. Beyond its effect on progression of renal failure, smoking is also an important cardiovascular risk factor in the patient with renal failure or the patient with a renal transplant.

SUMMARY

Smoking is one of the most important remediable renal risk factors. The exact mechanisms of smoking-induced renal damage remain to be determined. For all the above reasons cessation of smoking should be recommended to renal patients - a recommendation which is infrequently given and even less frequently followed.