Research On The Relationship Between Hyperbilirubinemia And Kidneyinjury In Full Term Newborns And Relative Influence Factors

Objective:To study the relationship and the relative influence factorsbetween neonatal hyperbilirubinemia and kidney injury in full term infants by measuring the contents of serum cystatin C,urinary microalbumin,urinary α1-microglobulin and urinary β2-microglobulin,and then evaluate the clinical significance of Joint detection of serum cystatin C and above-metioned three urinary microproteins.Methods:173 cases full term neonates were choosed as research objects,who were admitted to the First People’s Hospital of Yibin over the period of time from Marchto September 2015.136 cases newborns of them with hyperbilirubinemia were considered as jaundice group,and another 37 cases newborns without jaundice were considered as control group.Firstly,newborns in jaundice group weredivided into four subgroups according to the level of totalserum bilirubin(TSB)on admission:mild jaundice subgroup with 17 cases whose levels of TSB wereranged from209.3umol/L to 256.5umol/L;moderate jaundice subgroup with 56 cases whose levels of TSB wereranged from256.5umol/L to 342.1umol/L;severe jaundice subgroupwith 43 cases whose levels of TSB wereranged from 342.1umol/Lto 427.5umol/L and extremely severe jaundice subgroup with 20 cases whose levels of TSB were large for 427.5umol/L.And then compare the serum cystatin C and urinary microproteins among these groups.Secondly,jaundice group were divided into four groups according to the occurrence of kidney injury and the injured part of kidney:no kidney injury group(n=47),simple glomerulus injury group(n=17),simple renal tubule injury group(n=22)and mixed kidney injury group(n=50).Compare those indexes among above four groups such as gestational age,birth weight,sex,TSB,and so on.In the end,statistically significant resultes were analyzed by Logistic regressionto find the major influence factors.The study protocol was supported by the Institutional Review Board of Investigation in Human Being of First People’s Hospital of Yibin.Informed consent was obtained from the guardians of each newborns.Results:①Contents of serum cystatin C,urinary mAlb,urinary α1-MG and urinary β2-MG in the moderate,severe and extremely severe jaundicesubgroup were higher than those in the control group(P<0.05).But levels of serum cystatin C in the mild and moderate jaundice subgroup was lower than that in the extremely severe jaundicesubgroup(P<0.05).②89 cases infants had kidney injury among 136 cases newborns with hyperbilirubinemia,the incidence rate was 65.4%.Furthermore,the incidence rate of kidney injury rose with increase of TSB(P<0.05).③In the 89 cases patients with kidney injury,61 cases(68.5%)infants’ age were small for 7 days;19 cases(21.3%)infants’ age were between 8 to 14 days;Only 9 cases(10.1%)infants’ age were between 15 to 28 days.In addition,the type distribution of kidney injury were: simple glomerulus injury 17 cases(19.1%),simple renal tubule injury 22 cases(24.7%),mixed injury 50 cases(56.2%).④The newborns’ day-age on admission and course of disease in simple renal tubule injury group were smaller and shorter than those in no kidney injury group(P<0.05).The day-age of admission in mixed kidney injury group was smaller than that in no kidney injury group(P<0.05).Besides,the infants’ day-age,course of disease and the first appearance time of jaundice in simple renal tubule injury group and mixed kidney injury group were smaller,shorter,and earlier than those in simple glomerulus injury group respectively(P<0.05).⑤TSB on admission,day-age of admission and course of disease were shown as the major influence factors for neonatal kidney injury related to the hyperbilirubinemia in full term newborns on logistic regression analysis.⑥TSB on admission ranging from 220.6umol/L to 679.0umol/L wasfound topositively correlate with serum cystatinC,urinarymAlbandurinaryα1-MG respectively(r=0.274,0.343,0.218,P<0.05).There was positive correlation between TSB ranging from342.1umol/L to 679.0umol/Land urinary β2-MG(r=0.300,P<0.05).Positive correlation could be found between urinary mAlband urinary α1-MG(r=0.643),between urinary mAlband urinary β2-MG(r=0.526),between urinary α1-MG and urinary β2-MG(r=0.820)in the jaundice group(P<0.001).Urinary α1-MG was significantly negatively correlated with day-age of admission,the first appearance timeof jaundice and course of disease respectively(rs=-0.441,-0.273,-0.437,P<0.001).The same negative relationship could be observed between the urinaryβ2-MGandabove-mentionedthreeindexes(rs=-0.337,-0.220,-0.356,P<0.05).Conclusion:Hyperbilirubinemia could result in kidney injury,both glomerular filtration and tubular reabsorption could be impaired.The kidney injury caused by hyperbilirubinemia mainly occurred in the early newborn whose age was equal or less than 7 days.Mixed kidney injury mostly were the main,but tubular injury was earlier than glomerulus.The occurrence rate,severity of injury and injuryed part were associated with the neonates’ day-age,course of disease and the totalserum bilirubin.Joint detection of indexes including serum cystatin C,urinary mAlb,urinary α1-MG and urinaryβ2-MGwere available for the early diagnosis of kidney injury associated hyperbilirubinemia in full term newborns,and also could be used to evaluate the degree of kidey injury and judge injuryed part.