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Saudi Journal of Kidney Diseases and Transplantation
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RENAL DATA FROM THE ARAB WORLD  
Year : 2012  |  Volume : 23  |  Issue : 4  |  Page : 860-865
Risk factors associated with albuminuria in Kuwaiti adults with type 2 diabetes


Diabetes Unit, Department of Medicine, Al-Sabah Hospital, Kuwait

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Date of Web Publication9-Jul-2012
 

   Abstract 

There are no available data about the factors associated with diabetic nephropathy (DN) in Kuwaiti individuals with type 2 diabetes. This study was conducted on 154 consecutive Kuwaiti adults with type 2 diabetes who attended the diabetic out-patient clinic at Al-Sabah Hospital to determine the factors associated with albuminuria among them. Albuminuria was considered to be present if the urinary albumin:creatinine ratio test or 24-h collection was positive on two occasions. There were 102 (66.2%) women and 52 (33.8%) men, with a mean age of 49.1 ± 10.1 years and a median duration of diabetes for 6 years. Hypertension was found in 60.8% of the patients and 16.3% had an HbA 1c <7%. Albuminuria was found in 43.5% of the patients. The prevalence of microalbuminuria and macroalbuminuria was 27.3% and 16.2%, respectively. In the univariate analysis, the factors that were significantly associated with albuminuria were hypertension - both systolic and diastolic blood pressure levels, HbA 1c , retinopathy, duration of diabetes, and modality of treatment. Multiple logistic regression analysis indicated that hyper­tension was the main independent risk factor associated with albuminuria (OR 4.1, 95% CI 1.1- 15.0; P = 0.03). In conclusion, although albuminuria is common among Kuwaiti adults with type 2 diabetes, the prevalence is lower than that reported for other populations in spite of the poor glycemic control and the high prevalence of hypertension. Factors associated with albuminuria appear to be similar to other populations, and hypertension was the most independent factor. Early recognition and treatment of hypertension is an important strategy to prevent or delay DN as well as cardiovascular morbidity and mortality. A population-based study is warranted to confirm these findings and to search for genetic linkage for the development of DN.

How to cite this article:
Al-Adsani A. Risk factors associated with albuminuria in Kuwaiti adults with type 2 diabetes. Saudi J Kidney Dis Transpl 2012;23:860-5

How to cite this URL:
Al-Adsani A. Risk factors associated with albuminuria in Kuwaiti adults with type 2 diabetes. Saudi J Kidney Dis Transpl [serial online] 2012 [cited 2020 Aug 3];23:860-5. Available from: http://www.sjkdt.org/text.asp?2012/23/4/860/98189

   Introduction Top


Diabetic nephropathy (DN) is a progressive kidney disease and, at present, in many countries, is the most common cause of end-stage renal disease (ESRD). It accounts for 40% of new ESRD cases in the United States. The risk of developing DN starts with albuminuria, pro­gressing from micro- to macroalbuminuria. [1] Albuminuria in diabetes is strongly predictive of poor renal outcomes, cardiovascular morbi­dity and mortality. [2],[3] The Developing Educa­tion on Microalbuminuria for Awareness of Renal and Cardiovascular risk in Diabetes (DEMAND), a multinational cross-sectional clinic/center-based study, revealed that approxi­mately 50% of type 2 diabetic patients had micro- or macroalbuminuria, and Asians had a higher prevalence of albuminuria compared with Caucasian patients. [4] The main risk factors identified in DEMAND were HbA 1c , systolic blood pressure (BP), ethnicity, retinopathy, du­ration of diabetes, kidney function, body height, and smoking. In Kuwait, type 2 diabetes is a major public health problem, and cardiovascular disease is the leading cause of death. [5] National data have shown that DN is the leading cause of ESRD, accounting for 21.2% of the cases with ESRD. [6],[7] The prevalence of DN and the associated risk factors are currently unknown. This study was conducted to identify the factors that are associated with albuminuria in Kuwaiti adults with type 2 diabetes and whether they are dif­ferent from those reported for other populations.


   Patients and Methods Top


One hundred and seventy consecutive Kuwaiti adults with type 2 diabetes attending the Dia­betic Clinic at the Al-Sabah Hospital, between October 2000 and March 2005, were screened at their initial visit for albuminuria using the urinary albumin:creatinine ratio test (U-ACR) or 24-h urine collection. Albuminuria was mea­sured by the immunoturbidimetric method and was defined as positive if U-ACR was ≥1.5 mg/mmol and/or 24-h collection was ≥20 mg on two occasions. Macroalbuminuria was de­fined if 24-h collection was ≥300 mg. Other data collected included age, gender, diagnosis of hypertension, smoking status, body mass in­dex (BMI), BP, serum creatinine, and lipids. Diabetes-related data included diabetes dura­tion and treatment, HbA 1c , and diabetic retinopathy. Hypertension was defined as BP ≥140/90 mmHg or as current use of anti-hypertensive drugs. BMI (kg/m 2 ) was calcu­lated from weight and height measurements. HbA 1c was performed using turbidmetric inhi­bition immunoassay (Roche HB1c II kit). Gly-cemic control was diagnosed as good, accep­table, or poor when HbA 1c % was <7.0, 7.0- 8.0, or >8.0, respectively. Serum lipids were measured by the enzymatic method using Dade Dimension (Siemens, Becton-Dickinson, NJ, USA). Diabetic retinopathy was diagnosed using two-field fundus photography per eye, and results were presented as yes or no.


   Statistical Analysis Top


Data management and analysis were conduc­ted using the SPSS program. Continuous va­riables are presented as means ± SD, whereas categorical variables are presented as percen­tages. The χ2 test was used to test for diffe­rences in proportions between categorical va­riables, while the two-tailed t-test was used to compare between means. A P-value of <0.05 was considered to be statistically significant. Multiple logistic regression analysis was per­formed to adjust for the confounders and to determine independent effects of factors asso­ciated with diabetic albuminuria.


   Results Top


Patients' characteristics

Of the type 2 diabetics in the study, data was available for 154 patients. There were 102 (66.2%) women and 52 (33.8 %) men, with a mean age of 49.1 ± 10.1 years and a median duration of six years. Of the patients, 60.8% had hypertension, 38.3% had retinopathy, and 13.2% were current smokers. Mean systolic and diastolic BP were 135.5 ± 22.5 mmHg and 80.9 ± 10.3 mmHg, respectively. Systolic BP <130 mmHg and diastolic BP <80 mmHg were found in 35.7% and 26.6% of the pa­tients, respectively. Mean HbA 1c was 9.4 ± 2.5%, and 16.3% of the patients had an HbA 1c <7%. Mean BMI was 33.2 ± 7.4 kg/m 2 , and BMI >30 was found in 65.5% of the patients. Mean total cholesterol and triglyceride level was 5.7 ± 1.2 mmol/L and 1.9 ± 1.3 mmol/L, respectively. Mean Low density lipo-proteins-(LDL) and High density lipo-proteins (HDL-cholesterol were 3.7 ± 1.0 mmol/L and 1.2 ± 0.3 mmol/L, respectively. Of the 154 patients, 22.1% were being treated by diet only, 8.4% by metformin, 25.3% by sulphonylurea, 14.3% by com­bination oral therapy, 19.5% by insulin only, and 10.4% by combination insulin/oral therapy.

Albuminuria and associated factors

Albuminuria was found in 43.5% of the pa­tients. The prevalence of microalbuminuria and macroalbuminuria was 27.3% and 16.2%, res­pectively. Eleven patients (7.1%) had an im­paired renal profile (non-diabetic nephropathy was excluded). Personal and clinical charac­teristics of those with albuminuria are presen­ted in [Table 1]. The prevalence of albuminuria increased significantly with longer duration of diabetes (P <0.001). Of the newly diagnosed patients (n = 25), 20% had microalbuminuria. Albuminuria was significantly prevalent in pa­tients with systolic BP ≥130 mmHg and diastolic BP ≥80 mmHg and in those with retinopathy (P <0.001). Patients with albuminuria had higher HbA 1c (10.4 ± 2.5% vs. 8.7 ± 2.2%; P <0.0001) compared with patients without albuminuria. The risk for albuminuria increased from 20.0% in patients with good glycemic control to 54.6% in patients with poor glycemic control (P <0.001).Patients with BMI ≥30 had a higher prevalence of albuminuria com­pared with those with BMI <30 (P <0.001). The prevalence of albuminuria was highest among those treated with insulin and/or oral therapy and lowest among those treated with metformin (P <0.0001). Multiple logistic reg­ression analysis indicated that hypertension was the main independent factor associated with albuminuria (OR 4.1, 95% CI 1.1-15.0; P = 0.03). There were no significant differences between patients with and without micro-albuminuria with regard to gender, smoking status, triglyceride levels, or cholesterol levels.
Table 1: Personal and clinical characteristics of diabetic patients with and without albuminuria.

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   Discussion Top


In this hospital-based study, the prevalence of albuminuria due to type 2 diabetes among Kuwaiti adults was 43.5%, and hypertension was the most independent risk factor. The DEMAND study revealed that Asian patients had the highest prevalence of albuminuria (55%) whereas Caucasian patients had the lowest prevalence (40.6%). [4] Among the Asian countries, Saudi Arabia was the only contributing country; all other patients were from the Far East countries. The prevalence of micro-albuminuria found in our study is lower than that reported for Asian populations in the DEMAND study. Asians in the DEMAND study had higher HbA 1c levels but lower pre­valence of hypertension compared with Cauca­sians (7.8% vs. 7.2% and 53% vs. 68%, res­pectively). The patients in our study had higher HbA 1c levels (9.4%) and higher prevalence of hypertension (61%) than the Asian patients in the DEMAND study; however, the prevalence of albuminuria was lower. These findings sug­gest that several factors contribute to the variations in the prevalence of diabetic albuminuria among different populations, including the prevalence of hyperglycemia, hypertension, ethnicity, and a genetic predisposition. [8] Gen­etic linkage in the development of DN has been suggested. [9] The genetic correlation bet­ween urinary albumin excretion (UAE) and BP, particularly in the presence of diabetes, suggests that these traits may share common genetic determinants. [10]

In this study, 20% of the newly diagnosed type 2 diabetics were found to have micro-albuminuria. Mogensen et al reported that in newly diagnosed non-insulin dependant diabetes mellitus, about 40% of the patients showed a UAE rate above 15-20 μg/min. [11]

In this study, hypertension was the most sig­nificant independent factor associated with diabetic albuminuria. It is well documented that hypertension compounds and greatly increases the risk of microvascular complications, inclu­ding the risk of ESRD. [1] Each 10 mmHg re­duction in mean systolic BP led to 13% risk reduction of nephropathy. [12] Tight control of BP to keep it <130/80 mmHg, using renin- angiotensin-aldosterone system (RAAS) inhi­bitors, has been shown to prevent or delay renal complications as well as cardiovascular events in diabetic patients. [13]

Consistent with other studies, glycemic con­trol, duration of diabetes, BMI, and presence of retinopathy were significantly associated with albuminuria. The relationship of hyper-glycemia to the development and progression of diabetic retinopathy is well documented. [14]

The UKPDS has shown that for every 10% decrease in HbA1c, there was a 9% reduction in the risk of development of diabetic micro-albuminuria. [15] Similarly, longer duration of the disease increases the risk of albuminuria in patients with type 2 diabetes. [16] The association between albuminuria and increased BMI in individuals with type 2 diabetes has been re­ported and attributed to the glomerular deposi­tion of lipids and the activation of the RAAS. [17] For every 1 unit increase in BMI, there was an increase in UAE rate by 17%. [18] Studies have shown that weight loss is accompanied by reduction of proteinuria in chronic proteinuric nephropathies of different etiologies, including diabetes. [19] As reported, [16] we too found an association between diabetic retinopathy and albuminuria. Microalbuminuria in patients with type 2 diabetes is considered a marker of retinopathy. [20]

This study showed that albuminuria was found more frequently in patients treated with insulin or sulphonylurea as monotherapy and with com­bined insulin/oral therapy, and less frequently among those treated with metformin as mono-therapy or combined with other oral agents. The role of insulin in nephropathy was sug­gested by Klein et al. [21] The effect of metformin as monotherapy on UAE rate, compared with sulphonylurea, was inconsistent. [22],[23]

Inconsistent with other studies, [23],[24] gender, smoking status, triglyceride levels, and choles­terol levels were not found to be significantly associated with albuminuria in this study. This may be attributed to the small sample size of our study.

There are two limitations that need to be addressed regarding the present study. The first limitation is the small sample size, which is due to the fact that the majority of diabetic patients in Kuwait are followed-up in primary health care. Although this may affect the pre­valence of albuminuria, it should not affect the main objective of the study, which involves the factors associated with diabetic albuminuria. The second limitation is that the present study is a hospital-based study, which may have affected the results by showing a higher prevalence of albuminuria.

In conclusion, albuminuria is common among Kuwaiti adults with type 2 diabetes. Hyperten­sion is the most independent factor associated with albuminuria. Therefore, early recognition and treatment of hypertension is an important strategy to prevent or delay diabetic nephropathy as well as cardiovascular morbidity and mortality. The findings of this study indicate that factors associated with albuminuria among Kuwaiti adults are similar to those reported in other studies. However, the impact of these factors on the prevalence of albuminuria pro­bably varies among different populations, which suggests a genetic linkage for the deve­lopment of DN. A population-based study is warranted to confirm these findings and to search for genetic linkage for the development of DN. [25]

 
   References Top

1.American Diabetes Association. Standards of Medical Care in Diabetes. Diabetes Care 2010;33(Suppl 1):S11-61.  Back to cited text no. 1
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2.Gerstein HC, Mann JF, Yi Q, et al. Albuminuria and risk of cardiovascular events, death, and heart failure in diabetic and non-diabetic individuals. JAMA 2001;286:421-6.  Back to cited text no. 2
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3.Ninomiya T, Perkovic V, de Galan BE, et al. ADVANCE Collaborative Group. Albuminuria and kidney function independently predict cardiovascular and renal outcomes in diabetes. J Am Soc Nephrol 2009;20:1813-21.  Back to cited text no. 3
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4.Parving HH, Lewis JB, Ravid M, Remuzzi G, Hunsicker LG. DEMAND investigators. Prev­alence and risk factors for microalbuminuria in a referred cohort of type II diabetic patients: A global perspective. Kidney Int 2006;69:2057-63.  Back to cited text no. 4
    
5.Health and Vital Statistics Division, Ministry of Health. Health Kuwait 2005; XLIII.  Back to cited text no. 5
    
6.El-Reshaid K, Johny KV, Sugathan TN, Hakim A, Georgous M, Nampoory MR. End-stage renal disease and renal replacement therapy in Kuwait-epidemiological profile over the past 4 1/2 years. Nephrol Dial Transplant 1994;9: 532-8.  Back to cited text no. 6
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7.El-Reshaid W, El-Reshaid K, Kapoor M, Hakim A. Chronic renal disease in Kuwaiti nationals: A prospective study during the past 4 years. Ren Fail 2005;27:227-33.  Back to cited text no. 7
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8.Strojek K, Grzeszczak W, Ritz E. Risk factors for development of diabetic nephropathy: A review. Nephrol Dial Transplant 1997;12(Suppl 2):24-6.  Back to cited text no. 8
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9.Sale MM, Freedman BI. Genetic determinants of albuminuria and renal disease in diabetes mellitus. Nephrol Dial Transplant 2006;21:13-6.  Back to cited text no. 9
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10.Fogarty DG, Rich SS, Hanna L, Warram JH, Krolewski AS. Urinary albumin excretion in families with type 2 diabetes is heritable and genetically correlated to blood pressure. Kidney Int 2000;57:250-7.  Back to cited text no. 10
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11.Mogensen CE, Damsgaard EM, Frøland A, Nielsen S, de Fine Olivarius N, Schmitz A. Microalbuminuria in non-insulin-dependent diabetes. Clin Nephrol 1992;38 (Suppl 1):S28-39.  Back to cited text no. 11
    
12.Adler AI, Stratton IM, Neil HA, et al. Asso­ciation of systolic blood pressure with macro-vascular and microvascular complications of type 2 diabetes (UKPDS 36): Prospective ob­servational study. BMJ 2000;321(7258):412-9.  Back to cited text no. 12
    
13.Janet B. Improving Microvascular Outcomes in Patients with Diabetes through Management of Hypertension. Postgrad Med 2009;121:89-101.  Back to cited text no. 13
    
14.Klein R, Klein BE. Relation of glycemic con­trol to diabetic complications and health out­comes. Diabetes Care 1998;21(Suppl 3):C39-43.  Back to cited text no. 14
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15.Molyneaux LM, Constantino MI, McGill M, Zilkens R, Yuw DK. Better glycaemic control and risk reduction of diabetic complications in Type 2 diabetes: Comparison with the DCCT. Diabetes Res Clin Pract 1998;42:77-83.  Back to cited text no. 15
    
16.Torffvit O, Agardh E, Agardh CD. Albuminuria and associated medical risk factors: A cross-sectional study in 451 type II (noninsulin-dependent) diabetic patients. Part 2. J Diabet Complications 1991;5:29-34.  Back to cited text no. 16
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17.Praga M, Morales E. Obesity, proteinuria and progression of renal failure. Curr Opin Nephrol Hypertens 2006;15:481-6.  Back to cited text no. 17
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18.Rossi MC, Nicolucci A, Pellegrini F, et al. Obesity and changes in urine albumin/creatinine ratio in patients with type 2 diabetes: the DEMAND study. Nutr Metab Cardiovasc Dis 2010;20:110-6.  Back to cited text no. 18
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19.Praga M, Morales E. Weight loss and proteinuria. Contrib Nephrol 2006;151:221-9.  Back to cited text no. 19
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20.Wirta O, Pasternack A, Mustonen J, Laippala P, Lähde Y. Retinopathy is independently related to microalbuminuria in type 2 diabetes mellitus. Clin Nephrol 1999;51:329-34.  Back to cited text no. 20
    
21.Klein R, Klein BE, Moss SE. Prevalence of microalbuminuria in older-onset diabetes. Diabetes Care 1993;16:1325-30.  Back to cited text no. 21
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22.Nagi DK, Yudkin JS. Effects of metformin on insulin resistance, risk factors for cardiovas­cular disease, and plasminogen activator inhi­bitor in NIDDM subjects. A study of two ethnic groups. Diabetes Care 1993;16:621-9.  Back to cited text no. 22
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23.Amador-Licona N, Guízar-Mendoza J, Vargas E, Sánchez-Camargo G, Zamora-Mata L. The short-term effect of a switch from glibenclamide to metformin on blood pressure and microalbuminuria in patients with type 2 dia­betes mellitus. Arch Med Res 2000;31:571-5.  Back to cited text no. 23
    
24.Gall MA, Hougaard P, Borch-Johnsen K, Parving HH. Risk factors for development of incipient and overt diabetic nephropathy in patients with non-insulin dependent diabetes mellitus: Prospective, observational study. BMJ 1997;314:783-8.  Back to cited text no. 24
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25.Retnakaran R, Cull CA, Thorne KI, Adler AI, Holman RR. UKPDS Study Group. Risk fac­tors for renal dysfunction in type 2 diabetes: U.K. Prospective Diabetes Study 74. Diabetes 2006;55:1832-9.  Back to cited text no. 25
    

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Correspondence Address:
Afaf Al-Adsani
Diabetes Unit, Department of Medicine, Al-Sabah Hospital, P. O. Box 4078, Safat 13041
Kuwait
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DOI: 10.4103/1319-2442.98189

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   Statistical Analysis
   Results
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