Salt Intake And Its Influence Factors Among Patients With Chronic Kidney Disease:a Cross Sectional Study

Objective The aim of this thesis is to survey the quantity of salt taken in by patients with chronic kidney disease(CKD) and its related factors, providing evidence for clinical salt restriction guidance and the late intervention study.Methods Totally we surveyed605CKD patients who admitted to the three renal medical wards in Hangzhou traditional Chinese medicine hospital during September,2013and June,2014.24h urinary sodium excretion (24-UNa) was used to assess the salt intake. The social demographic characteristics, individual’s degree of salt taking, namely salt threshold, and the relevant clinical information were collected. Then the self-administered semi-structured questionnaire about salt restriction was used to find out the subjective and objective factors that affected CKD patients’salt restriction for further exploration.Results (1)88.8%of total CKD patients from the11regions of zhejiang province. Urine sodium excretion of this study cohort was126.0±58.1(19.6～421.8)mmol/d. Urine sodium excretion of211patients were below100mmol/d(34.9%of total patients), among which42patients were below50mmol/d(6.9%). While among the394patients whose urine sodium excretion were above or equal to100mmol/d,65patients were above200mmol/d(10.7%). Adjusting by urine creatinine,24h UNa/UCr was161.9(98.4,253.6)(9.0-854.0)mmol/g, and155patients were below100mmol/g(25.6%), among which36patients were below50mmol/g(6.0%). While among the450patients whose24h UNa/UCr were above or equal to100mmol/g,233patients were above200mmol/g(38.5%). The average salt threshold of this study cohort was (0.34±0.22)%, and the number of patients of low(<0.2%), medium(0.2%-0.4%), and high salt threshold(>0.4%) are62(10.2%of total patients),419(69.3%) and124(20.5%), respectively.(2) Multiple linear regression analysis indicated that BMI, gender, age,24h urine protein excretion, eGFR, place of residence(urban or rural), presence or absence of subjective symptoms(including hypodynamic, nausea, poor appetite, backache leg pain, and so on) and salt intake had linear regression relationship with the coefficient of determination(R2)0.170. Subgroups with a greater sodium excretion were as follows:man, those with higher BMI, those younger than65years of age, those with24h urine protein excretion more than3.5g/d, those with eGFR above or equal to60ml/min, those lived in urban and those who had no subjective symptoms. There is a significant correlation between salt threshold and24h urine sodium excretion among the patients whose eGFR above or equal to60ml/min(r=0.118, P=0.027), but it weaken or disappeared when eGFR<60ml/min.(3) The survey of semi-structured questionnaire showed that81.1%indicated their intention to reduce dietary salt intake, but only7.5%reported that they have used limited salt spoon,15.3%would read sodium contents of food labels when shopping and more than half of patients eaten pickles.90.4%reported that they knew renal patients should reduce salt intake, however,60.8%didn’t know the limit of salt.76.7%thought that low sodium diet have influenced their whole life so that they couldn’t adhere to it persistently.80.4%of family members reported that they favored a low sodium diets and would like to participate in, but only30.6%have light diets with their renal patients in fact. Through the open question, we found that patients’ psychological factors were also influenced their salt intake.Conclusion (1) The state of salt restriction of most CKD patients is unsatisfactory. There are two extreme phenomenon, namely salt limited overly and too much salt taken in.(2) Except the demographic characteristics, such as BMI, gender, age, place of residence(urban or rural), the severity of disease, like24h urine protein excretion, eGFR and presence or absence of subjective symptoms are also influence patients’ salt intake.(3) The will of salt restriction among patients couldn’t be accordance with their behavior, it is related to the subjective and objective factors about knowledge and skills of salt restriction, social psychological factors, family support, and so on.(4) The average salt threshold of CKD subjects is higher than normal individuals, and using salt threshold to evaluate patients’ salt intake should be prudent, whose eGFR below60ml/min.