Study On The Relationship Between Salt Intake And Early Renal Damage In Diabetic Patients With Hypertension

Background and purpose:Human disease spectrum has changed along with the dramatic lifestyle changes.Epidemiological studies have found that non-communicable diseases,including cancer,diabetes,cardiovascular diseases,and respiratory diseases have become a major cause of global mortality.Diabetes and hypertension are important causes of heart,brain,kidney and other target organ failure.Early detection of target organ damage and risk factors,along with early intervention can prevent or delay the target organ failure.Therefore,the early management of diabetes and hypertension is especially important.In our country,prevalence of diabetes and hypertension is high,while the awareness and control rate is relatively low.Meanwhile,diabetes and hypertension are often in combination,resulting in aggravation target organ damage.How to effectively prevent and control disease progression,and thereby prevent complications development are urgently needed in the prevention and control of diabetes and hypertension.The pathogenesis of diabetes and hypertension is complex,which is the result of genetic and environmental interactions.Unhealthy lifestyle is an important reason.Previous epidemiological survey clearly showed that high salt intake was correlated with increased incidence of cardiovascular disease,and a dose-effect relationship existed between the averaged daily salt intake and blood pressure.It is the world’s commonly recommended the most accurate method of assessing salt intake according to 24-hour sodium excretion.Clinically,urine albumin,serum creatinine and glomerular filtration rate are indicators to assess kidney damage,and 24-hour urinary albumin protein excretion is an effective indicator to assess early diabetic nephropathy,which is an important marker of early renal damage and cardiovascular disease prognosis.Plenty of previous clinical studies have found high salt intake increased risk of hypertensive and diabetic nephropathy damages.However,less is known about whether high salt increased early renal damage in diabetic patients with hypertension.Therefore,this study uses 24-hour urinary sodium excretion to assess the averaged daily salt intake,and examine whether salt intake(estimated by 24-hour urinary sodium)and urinary protein excretion(early kidney damage)are relevant,and thereby assessing the potential risk factors for early renal damage in diabetic patients with hypertension.Subjects:345 diabetic patients with hypertension(male n=188,female 157,aged 20 to 75 years old)admitted in the deparment Hypertension and Endocrinology in Daping Hospital were enrolled between January 2014 and January 2016,with 159 diabetic patients(male n=91,female 68)and 373 hypertensive patients(male n=183,female 190).Diagnosis criteria of type 2 diabetes mellitus(“Chinese guideline of diagnosis and prevention of type 2 diabetes mellitus 2013”): clinic symptoms including polydipsia,polyphagia,polyuria,weight loss and other symptoms combined with random blood glucose greater than or equal 11.1mmol / L,or morning fasting blood glucose higher than or equal to 7.0mmol / L,or 2h blood glucose after OGTT greater than or equal 11.1mmol / L.Exclude type 1 diabetes,specific diabetes and gestational diabetes special.Diagnostic criteria of essential hypertension(Guidelines for prevention and treatment of hypertension in China 2010): not in use of antihypertensive drugs,three times of blood pressure measurement in different days,systolic blood pressure(SBP)≥140 mm Hg and(or)diastolic pressure(DBP)≥ 90 mm Hg,or patients with previous history of hypertension and is now using antihypertensive drugs.Exclude secondary hypertension.Exclusion criteria of this study: glomerular filtration rate(eGFR)of less than 60 ml / min / 1.73m2 patients,e GFR is calculated using the modified MDRD equation(e GFR = 175 × [Scr(μmol / L)/88.4]-1.234 × Age-0.179 ×(0.79 Female).Methods: Collect patients general information,including age,medical history,family history,duration of diabetes,duration of hypertension,gender,previous diseases.Measurement of height,weight,body mass index(BMI = weight(kg)/ height2(m2)),waist circumference(WC),systolic blood pressure(SBP),diastolic blood pressure(DBP),and collect 24 hours urine.Measurement of total cholesterol(TC),high density lipoprotein cholesterol(HDL-c),fasting blood glucose,triglyceride(TG),serum sodium,glycated hemoglobin(Hb A1c),low-density lipoprotein cholesterol(LDL-c),microalbumin,serum creatinine,24 hours urine volume,urinary sodium and potassium in urine,urine creatinine.Salt intake is calculated in terms of the 24-hour urinary sodium excretion as following: the average daily salt intake(g / d)=(24h urinary sodium excretion(mmol / d)× 58.5 / 103).According to the qurtile of salt intake which is calculated in terms of the 24-hour urinary sodium excretion,we divided all patients into four groups: high-salt group(12.95 g/d ≤salt intake ≤23.46 g/d),medium-high salt group(10.07 g/d ≤salt intake ≤12.93 g/d),in medium-salt group(7.12 g/d ≤salt intake ≤10.05 g/d)and low-salt group(1.92 g/d ≤salt intake ≤7.11 g/d).All data were analyzed using SPSS 17.0 software analysis,P <0.05 was considered statistically significant.Inter quartile packet measurement data using one-way ANOVA,continuous data was analyzed using one-way ANOVA and chi-square test for the category data.Pearson analysis was performed for correlation analysis.Multiple linear regression analysis was performed for risk factors influencing microalbumin.Results:1.Significant differences are found in BMI,WC,uric acid,microalbumin,and eGFR among groups(P <0.05).High-salt group has higher WC,uric acid,microalbumin and BMI compared with low-salt group(P <0.05).2.Positive correlations are found between SBP,uric acid,24-hour sodium excretion,WC,TC,HDL-c and microalbumin in diabetic patients with hypertension.3.Daily salt intake,SBP,HbA1 c,uric acid are risk factors for microalbumin in diabetic patients with hypertension.4.Daily salt intake and microalbumin are positively correlated in patients with essential hypertension.5.Those diabetic patients with hypertenion compared with patients with dia betes or hypertension showed lower daily salt intake and higher microalbumin.Conclusion:1.High salt intake is a risk factor for early kidney damage in diabetic patients with hypertension,and higher average daily salt intake is associated with severe early kidney damage.2.SBP,HbA1 c,and uric acid are independent risk factors for early kidney damage in diabetic patients with hypertension.3.Dose-effects between high salt intake and microalbumin are found in hypertensive patients.4.Diabetic patients with hypertension are prone to early kidney damage than those patients with only hypertension or diabetes.