Infections and risk-adjusted length of stay and hospital mortality in Polish Neonatology Intensive Care Units
A. Ro´z˙an´ska
a,*, J. Wo´jkowska-Mach
a, P. Adamski
b, M. Borszewska-Kornacka
c, E. Gulczyn´ska
d, M. Nowiczewski
d, E. Helwich
e, A. Kordek
f, D. Pawlik
g, M. Bulanda
aaChairofMicrobiology,JagiellonianUniversityMedicalCollege,Krakow,Poland
bInstituteofNatureConservation,PolishAcademyofSciences,Krakow,Poland
cClinicofNeonatologyandIntensiveNeonatalCare,WarsawMedicalUniversity,Warsaw,Poland
dClinicofNeonatology,PolishMother’sMemorialHospital-ResearchInstitute,Lodz,Poland
eClinicofNeonatologyandIntensiveNeonatalCare,InstituteofMotherandChild,Warsaw,Poland
fDepartmentofNeonatalDiseases,PomeranianMedicalUniversity,Szczecin,Poland
gClinicofNeonatology,JagiellonianUniversityMedicalCollege,Krakow,Poland
1. Introduction
Nosocomialinfections are oneof themost frequentadverse eventsamonghospitalizedpatientsandareathreattoallpatients.
However, in some patient populations (e.g., those undergoing surgicalproceduresandinintensivecareunits[ICUs]),theriskof acquiring a nosocomial infection is particularly high. Among infantshospitalizedinICUs,andespeciallythoseofverylowbirth weight(VLBW),thereisagreaterriskofacquiringaninfection.The
increasedriskofinfectioninthisneonatalpopulationisassociated withalowergestationalage(asextremelyprematureinfantshave thinner, more permeable skin, underdeveloped innate and adaptiveimmuneresponses,andimmaturemucousmembranes) and their underlyingillness,1,2 as wellas the requirements for invasivetherapies,suchascentralvenousintravenouscatheters, andthehygienepracticesofhealthcareproviders.
Themostfrequentinfectionsinneonatalintensivecareunits (NICUs) arebloodstream infections,pneumonia,andnecrotising enterocolitis(NEC);lessfrequentcomplicationsareinfectionsof the urinary tract and the central nervous system.3,4 Infections amongVLBWinfantsmay,directlyorindirectly,resultinthedeath ofaninfant;however,evenwitheffectivetreatment,infectionsin thispopulationmaybeassociatedwithaprolongedlengthofstay (LOS).
ARTICLE INFO
Articlehistory:
Received2March2015
Receivedinrevisedform14April2015 Accepted23April2015
Keywords:
neonatalinfections verylowbirthweight in-hospitalmortality lengthofstay
ABSTRACT
Background: Theobjectivesofthisstudyweretoanalyzetheimpactofinfectionsonprolonginghospital staywithconsiderationofunderlyingriskfactorsanddeterminingthemortalityratesanditsassociation withinfections.
Methods:An electronic database developed from a continuous prospective targeted infection surveillanceprogramwasused inthestudy.Datawerecollectedfrom2009to2012infivePolish tertiaryacademicneonatalintensivecareunits(NICUs).Thelengthofstay(LOS)of2,003verylowbirth weight(VLBW)neonateswascalculatedasthesumofthenumberofdayssincebirthuntildeathoruntil reachingaweightof1,800g.
Results:The medianLOS forneonateswithinfections was twice ashigh asforneonates without infection.LOSwassignificantlyaffectedbytheoverallgeneralconditionoftheneonate,asexpressedby bothgestationalageandbirthweightaswellasbytheClinicalRiskIndexforBabies(CRIB)score;another independentfactorwaspresenceofatleastoneinfection.Riskofin-hospitalmortalitywassignificantly increased bymale sexand vaginal birth and was loweramong breastfed neonates. Deathswere significantlymorefrequentinneonateswithoutinfection.
Conclusions: ThegeneralconditionofVLBWinfantsstatisticallyincreaseboththeirriskofmortalityand LOS;thisisincontrasttothepresenceofinfection,whichsignificantlyprolongedLOSonly.
ß2015TheAuthors.PublishedbyElsevierLtdonbehalfofInternationalSocietyforInfectiousDiseases.
ThisisanopenaccessarticleundertheCCBY-NC-NDlicense(http://creativecommons.org/licenses/by- nc-nd/4.0/).
* Correspondingauthor.ChairofMicrobiology,JagiellonianUniversityMedical College,18CzystaStreet,31-121Krakow,Poland.Tel.:+48126330060;
fax:+48124233924.
E-mailaddress:rozanska@ifb.pl(A.Ro´z˙an´ska).
ContentslistsavailableatScienceDirect
International Journal of Infectious Diseases
j o urn a l hom e pa ge : ww w. e l s e v i e r. c om/ l o ca t e / i j i d
http://dx.doi.org/10.1016/j.ijid.2015.04.017
1201-9712/ß2015TheAuthors.PublishedbyElsevierLtdonbehalfofInternationalSocietyforInfectiousDiseases.ThisisanopenaccessarticleundertheCCBY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).
Payneetal.,intheirstudyof17hospitalsintheUnitedStates, determineda 19.7% incidence of central line-associated blood- stream infections (CLABSIs), which were associated with an increase in the marginal cost of hospitalization for a single neonate from$5,875 to$12,480. Rates of ventilator-associated pneumonia(VAP)intheNICUwerereportedintherangeof0.2to 1.6per1000person-daysofventilation,accordingto2011data reported in National Healthcare SafetyNetwork (NHSN) in the UnitedStates.3AccordingtotheNHSN,VAPinNICUsaccountedfor approximatelyone-fifthofallinfections,and CLABSIsfornearly 80%.InastudybyRosenthaletal.,cruderatesforexcessmortality associatedwithCLABSIsandVAPweredeterminedtobe27.7%and 17.9%,respectively.5
Theobjectivesofthepresentstudyweretodetermine:
1)theassociationbetween the presenceof infections in VLBW neonatesandtheLOSforneonatessurvivinguntiltheyreacha weightof1,800grams;
2)the association between the presence of infections and in- hospitalmortality;and
3)if infection is an independent risk factor for the above mentionedoutcomes,withconsiderationofotherriskfactors unrelatedtoinfection,
2. Materialsandmethods
An electronic database, created as a result of continuous prospective surveillance of infections, that focused on VLBW neonateswas used in the study. Data werecollected between January1,2009andDecember31,2013atfivetertiaryacademic NICUs that took part in the Polish Neonatology Surveillance Network(PNSN).ThePNSNisaprospectivenationalsurveillance systemfor themostrelevant infections in VLBWinfants(birth weight<1,500g)inPoland.Theseurbantertiaryteachinghospital NICUsprovidecarefor 20%of allVLBWinfantsbornin Poland annually.Detailsofthefollowingvariableswerecollectedforall VLBWinfants:birthweightandgestationalage,gender,multiple pregnancy,type ofdelivery, informationon thesituationat the timeofdelivery(e.g.,chorioamnionitis),generalphysicalstateas measuredbyApgarscoresat1and5minutesandtheCriticalRisk Index for Babies (CRIB) score, and detailed data on antibiotic treatment. The PNSN recorded severe infections, including bloodstream infections (CLA-BSI and other cases of BSI) and pneumonia(PNEU),observedduringhospitalization(fromadmis- siontodischarge, transfer,or death).NICUparticipation in the PNSNwasvoluntaryandconfidential.
UtilisationofdatacollectedbythePNSNforscientificpurposes was approved by the Bioethics Committee of Jagiellonian University Medical College (no. KBET/221/B/2011). All data entered into the electronic database and analysedduring the compilationof this article were previously de-identified.Data wereobtained duringroutine treatmentanddiagnostic proce- duresperformedduringpatients’hospitalisation.Beforeanalysis, incomplete records (without date of birth/discharged/death;
gender; data about infections) were deleted and, as a result, complete records of 1,038 neonates without infections and 965neonateswithBSIs,PNEU,orothertypesofinfectionwere available.
Neonateswithbirthweight lessthan1,500g(consideredas VLBW)were included in the study.Cases of early and/or late infections(BSI,PNEU,NEC)inneonates(onlywithclinicalsigns ofinfection)weredefinedaccordingtoGastmeieret al.6,with somemodification. Standard indicators of thegeneral state of neonateswereApgarscores(at1and5minutes)andCRIBscores.
Diagnosisofchorioamnionitiswasbasedonclinicalevaluation
without the need for microbiological or histopathological examination.7 Determination of the microbial species and evaluationofdrugresistancewereconductedbylocalmicrobio- logiclaboratories.
Thedeviceutilizationrate(calculatedbydividingthenumber ofdevicedaysbythetotalnumberofpatientdays)was0.45for centralvenouscatheters(CVCs),0.16forperipheralintravenous catheters(PVCs),0.25formechanicalventilation(MV),and0.18for continuouspositiveairwaypressure(CPAP).LOSforneonatesin theNICUwascalculatedasthesumofthenumberofdayssince birthuntildeathordischargefromthehospital.Inthreeofthefive participatingNICUs,thisoccurredatreaching34to35weeksof gestationalageandintwo,onreachingaweightof1,800g.
Datawere analysed in two ways. The relationship between particularclinicaleffectsandsingleelementsofcareprocedures were investigated with univariate statistics. The selection of statisticaltechniquesdependedonthetypeanddistributionofthe variablesanalysed.Ifbothdependentandindependentvariables werecategorical,qualitativefrequencytestssuchaschisquareor likelihood ratio were used. If the dependent variable was continuous (e.g.,LOS or birth weight) and the predictors were qualitative,theMann-WhitneyUtestfordichotomouspredictors orKruskal-Wallistestwerecalculated.Morepowerfulparametric tests(e.g.,analysisofvarianceorstudentt-test)couldnotbeused becauseof non-normal distributionofthedependent variables.
Commoneffectsofseveralvariablesonmortalityprobabilitywere analysed with a generalized linear model. Because of the dichotomous character of the effect and different types of predictors, a model was constructed with an assumption of a binominaldistributionofthedependentvariableandlogit-linked function.Theassumedcriticalvalueofthesignificancelevelwas p<0.05.
3. Results
The PSNS included 2,003 VLBW neonates, including 372 extremelylow birthweightinfants(18.6%)withabirth weight upto750g,516infants(25.8%)withbirthweightrangingfrom 751to999g,and1,115infants(55.7%)withbirthweightranging from1,000to1,500g(Table1).
3.1. Riskofinfection
Theriskofinfectionsignificantlycorrelatedwithbirthweight;
thestrongestcorrelationwasfoundinneonateswithbirthweights rangingfrom750to999g(Table1).Also, deliveryat28 weeks gestationorearlierwasassociatedwitha3.5-foldhigherriskof infection as compared to VLBW neonates born at 28 weeks gestationorlater.Significanceofthecorrelationbetweeninfection andinterventionssuchasCVC,MV,andCPAP,andmediansdaysof useof theseinterventionswas determined;risk of infectionin neonates withexposure to theseinterventions wasfive to ten timeshighercomparedtono exposure(Table1).Neonateswith infectionsweretreatedwithantimicrobialagentsfora meanof 19days.
3.2. In-hospitalmortality
Medianbirthweightandgestationalageofneonateswhodied were significantly lower, similar to general neonate condition expressed by Apgar scores at 1 and 5minutes. The highest mortalityratewasfoundinneonateswithbirthweightlessthan 750g(50.5%)and/ordeliveredinthe28thweek ofgestationor later(30.1%).However,risk ofin-hospitalmortalitywassignifi- cantly increased by male sex and vaginal birth. The risk of
in-hospitalmortalitywaslower inbreastfed neonates, showing strongtrend(p=0.019;OR0.78;95%CI0.578-1.064)–Table1.
Invasive procedures (CVC, PVC, MV, CPAP) were used for a longerperiod oftime intheneonateswhosurvivedtohospital discharge in comparison with neonates who did not survive (Table2).Neonataldeathsweresignificantlymorefrequentamong neonateswithoutinfection(Table1),and,atthesametime,the average LOS was 19 times shorter (because of early deaths) comparedtosurvivingneonateswhoweredischargedfromthe NICU(Table2).
3.3. Lengthofhospitalstay
ThemedianLOSforallneonateswithinfectionswastwiceas highas forneonates withoutinfection(44 days vs. 22 days)– Table1.However, taking intoconsiderationonlyneonateswho were discharged from the NICU as a result of achieving their expectedbirthweight(i.e.,a successfultreatment),themedian stayforneonateswithoutinfectionwaslonger-30days,compared withamedianstayof45daysforneonateswithatleastonetypeof infection – Table 2. Moreover, specific infections or multiple infections in a neonate affected LOS to varying degrees. The occurrenceofmorethantwotypesofinfectionresultedinatwo- fold prolongationofLOSfor neonatesin theNICU(60days vs.
30dayswithoutinfections);PNEUandBSIwereassociatedwitha longerLOS,byapproximately20days(Table2).
3.4. Independentpredictoroflengthofstaybymultivariateanalysis
TheLOSintheNICUwassignificantlyaffectedbythegeneral overallcondition of theneonate,expressed by bothgestational weight and gestational age as well as CRIB scores. The other independentfactorwasthepresenceofatleastoneinfection.
4. Discussion
Infections in neonates, particularly those with the lowest weight,remainoneofthemostimportantproblemsinmodern medicine.Oneissueisanincreasingnumberofprematurebirths, aswellastheincreaseinmultiplepregnancies.8,9Anothercause mightbetheimprovementinthesurvivalrateofVLBWneonatesin modernNICUs,whicharebetterequippedforlife-savingintensive carenowadaysthaninthepast.
OurresultsformortalityandLOSarethefirsttobereportedby thePNSNandfromCentralEuropebasedonanationalprogramfor infectionsurveillanceandcontrolinNICUs.Ourpreviousreporton this population within the PNSN focused on various types of infection or their aetiology.10–13 In the study population, the epidemiologyandmicrobiologyofinfectionsdidnotdifferfrom dataobtainedinothermulti-settingstudies.14,15
It is thought that NICU admission and treatment may be connectedwithahighincidenceandmortalityratesrelatedtoboth early-andlate-onsetinfections.16–22InPoland,inastudiedgroup of neonateswithsymptomsof early-onsetinfections (EOIs), an increasedcase-fatalityratewasnotobserved.Earlymortality(i.e.,
<7days afterdelivery) was17%for early-onsetBSIand 8% for early-onsetPNEU.Thecase-fatalityrateassociatedwithlate-onset BSI was 7.5%.10,11 However, our present results indicate that infectionsarenotasignificantfactorforincreasingVLBWneonatal mortality.Thebirthweightandgestationalageprovedtobemore important.Also,otherauthorshaveconfirmedourobservations.
Infantsbornatthethresholdofviability(thosewithagestational ageof23to25weeks,abirthweight<500g,orboth)areatthe greatest risk for a poor outcome. For example,in theVermont Oxford Network(a voluntarynetwork for data collection from morethan650NICUsintheUnitedStatesandworldwide),among infantsbornbetween1996and2000withabirthweightof401to Table1
BaselinecharacteristicsofVLBWnewbornswithandwithoutinfections
Baselinecharacteristics InfantswithinfectionsN=965 InfantswithoutinfectionsN=1038 OR(95%CI) p
medianbirthweight(grams)(IQR) 960(770–1200) 1150(890–1340) NA <0.001
<750gramsn(%) 208(21.6) 164(15.8) 1.46(1.167-1.837) <0.001
750-999gramsn(%) 326(33.8) 190(18.3) 2.28(1.853-2.799) <0.001
1000-1249gramsn(%) 241(25.0) 281(27.1) 0.897(0.734-1.095) <0.001
1250-1499gramsn(/%) 190(18.5) 403(38.0) 0.39(0.316-0.473) <0.001
mediangestationalage/(IQR) 28.0(26–30) 29.0(27–31) NA <0.001
lessthanorequalto28weeksn(%) 626(64.87) 355(34.20) 3.55(2.955-4.271) <0.001
morethan28weeksn(%) 339(35.13) 683(65.80) <0.001
femalesexn(%) 442(46.53) 508(53.47) 0.88(0.7397–1.051) -
malesexn(%) 523(49.67) 530(50.33) -
CCn(%) 766(47.25) 855(52.75) 0.82(0.658–1.030) -
vaginalbirthn(%) 198(52.11) 182(47.89) -
breastfeedingn(%) 79(42.02) 106(56.38) 0.78(0.578–1.064) 0.019
CVC[days]median(IQR) 11(0–24) 1(0–8) NA <0.001
MV[days]median(IQR) 5(0–19) 1(0–20 NA <0.001
CPAP[days]median(IQR) 8(2–18) 0(0–3) NA <0.001
antibiotics[days]median(IQR) 19(13-29) 4(1–7) NA <0.001
CRIBmedian(IQR) 4(1–7) 2(1–7) NA -
Apgar1median(IQR) 6(4–7) 6(4–7) NA <0.001
Apgar5median(IQR) 6(5–7) 7(5–8) NA <0.001
chorioamnionitisn(%) 76(53.15) 67(46.85) 1.24(0.881-1.742) -
PROMn(%) 268(56.07) 210(43.93) 1.52(1.233-1.864) <0.001
multiplebirthn(%) 221(42.26) 302(57.74) 0.72(0.592-0.885) 0.002
Outcomes
LOS[days]median/(IQR) 44(29–58) 22(1–13) NA <0.001
Dischargen(%) 779(56.65) 596(43.35) 3.106(2.538-3.801) <0.001
Transfern(%) 101(33.33) 202(66.67) 0.49(0.374-0.626) <0.001
Diedn(%) 85(26.23) 239(73.77) 0.32(0.247-0.421) <0.001
IQR-InterquartileRange;ORoddsratio;95%CI95%confidenceinterval;NAnotavailable.
CCCaesareansection;CPAPcontinuouspositiveairwaypressure;CRIBCriticalRiskIndexforBabies;CVCcentralvenouscatheter;LOSlengthofstay;MVmechanical ventilation;PROMprematureruptureofmembranes;VLBWverylowbirthweight.
500gandameangestationalageof23.2weeks,themortalityrate was83%.23ThisissimilartotherateamongsurveyedPolishVLBW neonates(75%).10Theriskofdeathdecreasessignificantlywithan increaseinbirthweight.24Overall,inthegroupofVLBWneonates, generalin-hospitalmortality(notassociatedwithinfections)was 16.7%inItaly25and14.3%inKorea.26Indevelopingcountries,in- hospitalmortalityis higher;28.1% inIran27and 35%inIndia.28 Unfortunately,theneonatesin-hospitalmortalitymayalsodepend onotherriskfactors.InastudybyApisarnthanaraketal.regarding VAPinextremelypretermneonates,thein-hospitalmortalityrate was27%.Insuchdefinedpopulations,VAPwastheonlysignificant riskfactorformortality.29
Innearlyhalf(48.2%)ofallstudiedVLBWneonates,atleastone clinicalinfectiondevelopedduringthetimeperiodstudied.Butit wasfoundthat infection wasnot a factor affectingthe risk of neonatal death. Conversely, infections were observed mainly among the neonates that survived. Infection was one of the independentfactorsinfluencingtheprolongationoftheneonate’s stayintheNICU.However,atthesametime,theoccurrenceofone ormoreclinicalinfections,aswellasthesiteofinfection,hada variableeffectonLOS.Theoccurrenceofmorethanoneinfection wasassociatedwiththelongestLOSforneonatesintheNICU;the medianLOSwas60daysversus30daysforneonateswithoutan infection.Amongneonates who developedone infection,PNEU was associated with the highest median LOS as compared to neonateswithoutaninfection(51daysvs.30days).Thisvalueis onlyslightlyhigherthanthatforBSIs,wherethemedianLOSwas 48days.
For studies regarding prolonged LOS by neonates in NICUs conducted by other authors, results that differ from the data presentedinourwork, werereviewed.Apisarnthanaraketal.29 observedamedianLOSforneonateswithVAPalmostthreetimes higher than that for neonates in Polish NICUs (138 days [SD
13-361]vs.82days[SD8-197]),whereVLBWneonatesaccounted foronlyabout30%,withamediangestationalageof25weeks.In the cited study, the median LOSfor all neonateswas 30 days (similartothemedianLOSofVLBWneonateswithoutinfectionin PolishNICUs)and76daysforVLBWneonates.Thedifferencesin LOS seen in both studies may be due to different neonate populationsincludedinthetrials.IntheUSstudy,onlyneonates whorequiredMVwereeligibleforinclusion,whereasinthePolish study,MVwasusedinasmallpercentageofneonates(utilization ratio:0.25).
InastudybyPayneetal.30conductedin17UShospitalsthat evaluatedcostsandprolongedLOSforVLBWinfantswithBSI,the mean LOS of neonates with BSI ranged from 48 to 101 days (dependingonbirthweight),comparedwithameanLOSof32to 85daysforneonateswithoutinfections.Themeanprolongationof LOSsecondarytoBSIwas,therefore,recordedatthelevelfrom 13to17days–theupperlimitofthisrangeisthusapproximateto theresultfromPolishNICUs,i.e.,themedianprolongationofLOS by 18 days in neonates with BSI. The analysis of data by multivariate logistic regression demonstrated, however, an in- crease inLOS forVLBW neonateswithBSI by4 to 7days and associatedcostsfallingwithintherangefrom5,875USDto12,480 USD. In contrast, PolishLOS values weresimilar to theresults obtainedinaGermanstudy(NeoKISS)byDenkeletal.31
Despitenearly20years ofexperiencewithmoderninfection controlinPolandandtheorganisationofsurveillanceaccordingto internationalstandards,32therearevirtuallynostudiesconcerning thecostofinfections.Andreportsofthistype,forbothadultsand neonates, arelimited becauseof thesocio-economic conditions andhealthcareorganizationsinPoland.
AnattempttoestimatethecostsofNICUcareforpremature infants wasundertaken by Krawczyk-Wyrwicka, who analysed costsinoneNICU,33,34particularlythecostsassociatedwithBSI.
Table2
In-hospitalmortalityofVLBWneonatesinthePNSN
Baselinecharacteristics Deathin-hospitalN=324 DischargeN=1375 OR(95%CI) p
medianbirthweight(grams)(IQR) 750(600–1000) 1105(900–1320) NA <0.001
<750gramsn(%) 157(50.48) 154(49.52) 7.45(5.662–9.812) <0.001
750-999gramsn(%) 85(20.00) 340(80.00) 1.08(0.821–1.427) <0.001
1000-1249gramsn(%) 48(11.06) 386(88.94) 0.45(0.321–0.619) <0.001
1250-1499gramsn(/%) 34(6.65) 495(96.87) 0.21(0.144–0.302) <0.001
mediangestationalage/(IQR) 26.0(24–28) 29.0(27–31) NA <0.001
lessthanorequalto28weeksn(%) 261(30.10) 606(69.90) 5.26(3.914–7.061) <0.001
morethan28weeksn(%) 63(7.62) 764(92.38) 0.19(0.144–0.259) <0.001
femalesexn(%) 132(16.42) 672(83.58) 0.72(0.563–0.919) <0.001
malesexn(%) 192(21.45) 703(78.55)
CCn(%) 224(16.37) 1144(83.63) 0.45(0.342–0.593) <0.001
vaginalbirthn(%) 100(30.30) 230(69.70)
breastfeedingn(%) 3(1.73) 170(98.27) 0.07(0.021-0.209) <0.001
CVC[days]median(IQR) 1(0–4) 7(0-180 NA <0.001
MV[days]median(IQR) 2(1-60 1(0–8) NA <0.001
CPAP[days]median(IQR) 0(0–0) 5(1–14) NA <0.001
antibiotics[days]median(IQR) 2(1–6) 13(6–23) NA <0.001
CRIBmedian(IQR) 8(6-120 2(1–5) NA <0.001
Apgar1median(IQR) 3(1–5) 6(5–7) NA <0.001
Apgar5median(IQR) 4(1–6) 7(6–8) NA <0.001
chorioamnionitisn(%) 25(20.490 97(79.51) 1.10(0.697-1.740) -
PROMn(%) 75(18.07) 340(81.93) 0.92(0.689-1.220) -
multiplebirthn(%) 87(19.33) 363(80.67) 1.02(0.779-1.345) -
Outcomes:LOS(days)
median/(IQR) 2(0–8) 38(27-530 NA <0.001
Noinfection-median/(IQR) 0(0–3) 30(23–38) 3.68(2.807-4.812) <0.001
Atleast1infection-median/(IQR) 12(4–23) 45(32–59) 0.27(0.208-0.356) <0.001
BSI-median/(IQR) 12(4–21) 48(33–61) 0.38(0.282-0.516) <0.001
PNEU-median/(IQR) 19(9–26) 51(39–65) 0.29(0.203-0.425) <0.001
>oneinfection-median/(IQR) 26(16–40) 60(48–69) 0.32(0.210-0.495) <0.001
IQR-InterquartileRange;ORoddsratio;95%CI95%confidenceinterval;NAnotavailable.
BSIbloodstreaminfection;CCCaesareansection;CPAPcontinuouspositiveairwaypressure;CRIBCriticalRiskIndexforBabies;CVCcentralvenouscatheter;LOSlengthof stay;MVmechanicalventilation;PNEUpneumonia;PROMprematureruptureofmembranes;VLBWverylowbirthweight.
The cost estimated in these studies as per person-day of hospitalizationinanNICUrangedfrom608to822PLN (203to 274USD), and thecost per person-dayof hospitalization for a neonatewithBSIwas2,152PLN (717 USD).Linkingtheresults obtainedin ourstudyconcerning themedianprolongedLOSof VLBWneonateswithBSIandthecostperperson-dayestablished byKrawczyk-Wyrwicka,allowedfortheestimationofthecostof prolongedLOSinPolandat12,806USD;thatis,attheupperlimitof costsdeterminedbyPayneetal.,30takingintoaccountmultivari- atelogisticregression,andthusofextensionofashorterstayby aboutone-thirdthanestablishedinthisstudy.
Rosenthaletal. reported values for prolongedLOS inNICUs similar tothose obtained in our present study; for CLABSIs at 18.4 days and for VAP at 25.6 days (based on data from the International Nosocomial Infection Control Consortium and NHSN),butwithoutacostanalysis.5Rosenthaletal.alsoreported a pooledcrudemortalityrate(undefined)for neonateswithout infection,at12.5% and rangingwithinthelimitsfrom15.2% to 25.3%amongneonateswithinfections.Thein-hospitalmortality rateofVLBWneonatesinourpresentstudywas16.2%.
Analysisoftheinfluenceofinfection,asconductedinthisstudy, ontheLOSamongVLBWneonateshospitalizedin PolishNICUs revealed a significant correlation between infection and this outcome.However,inordertoobtainaworthwhileassessmentof thiscorrelation,itisnecessarytoalsoassessthegeneraloverall conditionoftheneonateasexpressedbysuchessentialparameters asbirthweight,gestationalage,andCRIBscore,which,apartfrom infection, may also substantially affect the LOS as well as in- hospitalmortality(Table3).AsignificantcorrelationbetweenCRIB score, gestational age, and birth weight and the prognosis or treatmentoutcomeshasalsobeenfoundinotherstudies[35,36]
5. Conclusions
The general overall condition of VLBW infants statistically increasesbothmortalityandLOS,incontrasttoinfection,which significantlyprolongedonlytheLOSintheNICU.
Acknowledgments
Foundingsource:Nofundingwassecuredforthisstudy.
Financial Disclosures: The authors: Anna Ro´z˙an´ska, Jadwiga Wo´jkowska-Mach, PawełAdamski,Maria Borszewska-Kornacka, Ewa Gulczyn´ska, Marek Nowiczewski, Ewa Helwich, Agnieszka Kordek, Dorota Pawlik, Małgorzata Bulanda have no financial relationshipsrelevanttothisarticletodisclose.
Conflict of Interest: The authors: Anna Ro´z˙an´ska, Jadwiga Wo´jkowska-Mach, Paweł Adamski,MariaBorszewska-Kornacka, Ewa Gulczyn´ska, Marek Nowiczewski, Ewa Helwich, Agnieszka Kordek,DorotaPawlik, MałgorzataBulandahaveno conflictsof interestrelevanttothisarticletodisclose.
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IndependentpredictorofLOSofVLBWnewborns,whoweredischargedfromthe ward(withoutneonateswhodiedorweretransferred)
Pvalue Lower95%CI Upper95%CI
birthweight <,001 -0.0495 -0.041
gestationalage <,001 -0.203 -0.883
femalesex 0.7 -0,550 0.777
CC 0.6 -4.605 8.329
CRIB <,001 0.100 0.687
Apgar1 0.3 -0.920 0.281
Apgar5 0.6 -0.435 0.732
choriamnionitis 0.9 -0.936 1.131
PROM 0.8 -0.948 0.696
notlessthan1infection <,001 -3.074 -1.462 adjustedforbirthweight;gestationalage;ClinicalRiskIndexforBabies,CRIB;score, Apgar1-and5-minutescores,typeofbirth,gender,chorioamnionitis,PROMandat least1infection.
ORoddsratio;CIconfidenceinterval;
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