Incidence of the acute renal failure in the intensive care unit at the General Hospital of Mexico: Risk factors and associated morbidity and mortality

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www.elsevier.es/hgmx

´

ORIGINAL

ARTICLE

Incidence

of

the

acute

renal

failure

in

the

intensive

care

unit

at

the

General

Hospital

of

Mexico:

Risk

factors

and

associated

morbidity

and

mortality

J. Herrera-Méndez

a_,_∗

_,

_L.D.

_{Sánchez-Velázquez}

b

_,

_A.

_{González-Chávez}

a

_,

G. Rodríguez-Terán

c

a_Servicio_de_Medicina_Interna,_Hospital_General_de_México,_Mexico b_Unidad_de_Terapia_Intensiva,_Hospital_General_de_México,_Mexico c_Hospital_ABC,_Mexico

Received12June2014;accepted29April2015 Availableonline21July2015

KEYWORDS Acuterenalfailure; Intensivecareunit; Riskfactors; Incidence

Abstract

Background: The acuterenal failure (ARF)contributes toa longerhospital stay, morbidity, mortalityanduseofresourcesincriticalpatients.

Theestimateofitsincidencewasdifﬁcult,mainlyduetothelackofagenerallyaccepted deﬁnition.

Objective:Todeterminetheincidence,riskfactorsandeffectsoftheARFincriticalpatients. Materialandmethods: Studyofprospectivecohort.PatientshospitalisedintheIntensiveCare Unit(ICU)wereincluded.Thepopulationwasdividedinto4groups:A:withoutARF;B:with ARFatICUadmission;C:ARFdevelopedattheICU;andD:ARFattheadmission,solvedand developedagainattheICU.Descriptiveandinferentialstatistics(Student’st,2_and_ANOVA). Results:Of360patients,50.5%weremen.Themeanagewas49years.Fromthetotal,145 (40.3%)didnotdevelopARF(groupA).Themaincomorbiditieswerediabetesmellitusandhigh bloodpressure.Patientswithsepsis,shockandmultipleorganfailureshowedagreaterARF frequency(p<0.001).TheARFincidenceswere30.3%ingroupB,20.3%ingroupCand9.2% ingroupD.Theattributablemortalitywas11.8%,16.6%and26.1%,respectively.Therewasa higheruseofresourcesingroupsCandD.

Conclusions:TheARFincidenceincriticalpatientsrangesfrom9.2%to30.3%.Themainrisk factorsaresepsis,shockandMODS.

∗_{Corresponding}_author_at:_Servicio_de_medicina_interna,_Unidad_103-B,_Hospital_General_de_México,_O.D.,_Balmis_148,_C.P.₀₆₇₂₆_México, DF,Mexico.

E-mailaddress:[email protected](J.Herrera-Méndez). http://dx.doi.org/10.1016/j.hgmx.2015.04.005

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PALABRASCLAVE Lesiónrenalaguda; Unidaddecuidados intensivos;

Factoresderiesgo; Incidencia

Incidenciadelalesiónrenalagudaenlaunidaddecuidadosintensivosdelhospital generaldeMéxico:factoresderiesgoymorbi-mortalidadasociada

Resumen

Antecedentes: Lalesiónrenalaguda(LRA)contribuyeamayorestanciahospitalaria, morbili-dad,mortalidadyconsumoderecursosenpacientescríticos.

Estimarsuincidenciaeracomplicado,principalmenteporlafaltadeunadeﬁnición general-menteaceptada.

Objetivo: Determinarincidencia,factoresderiesgoyefectosdelaLRAenpacientescríticos. Materialymétodos: Estudiodecohorteprospectiva.Seincluyeronpacienteshospitalizadosen UnidaddeCuidadosIntensivos(UCI).Lapoblaciónsedividióen4grupos:A.SinLRA;B.con LRAalingresoaUCI;C.LRAdesarrolladaenUCI;y,D.LRAalingreso,resueltaynuevamente desarrolladaenUCI.Estadísticadescriptivaeinferencial(tdeStudent,2_y_ANOVA).

Resultados: De360pacientes,50.5%fueronhombres.Laedadmediafue49a˜nos.Deltotal,145 (40.3%)nodesarrollaronLRA(grupoA).Lasprincipalescomorbilidadesfuerondiabetesmellitus e hipertensión arterial. Los pacientescon sepsis,choque y fallamultiorgánica presentaron mayorfrecuenciadeLRA(p<0.001).LasincidenciasdeLRAfueron30.3%enelgrupoB,20.3% en elgrupoCy 9.2%enelgrupo D.La mortalidad atribuiblefuede 11.8%,16.6% y26.1%, respectivamente.HubomayorconsumoderecursosenlosgruposCyD.

Conclusiones:LaincidenciadeLRAenpacientescríticososcilaentre9.2%y30.3%.Los princi-palesfactoresderiesgosonsepsis,choqueySDOM.

Introduction

Acuterenalfailure(ARF)isafrequentproblemwhich signif-icantlycontributestomorbidityandmortality,particularly incriticalpatients.Itischaracterisedbythesuddenlossof thekidneycapacitytoexcretewasteproducts,concentrate urine, preserve electrolytesand keep the water balance. Itis particularlycommon inthe intensivecare unit(ICU), whereitisassociatedtoa50---80%mortality.1---4

InMexico,differentstudieshavereporteddiffering

inci-denceandmortalityrates becausetherewasnoaccepted

ARFdeﬁnition.5---9

Theaimofthisstudyistoassesstheincidence,risk

fac-tors,effectsonthemorbidity,mortalityanduseofresources

in patients whowere admitted tothe intensive care unit

(ICU)attheuniversitygeneralhospitalinMexico,usingthe

updateddeﬁnitionofthegroupAcuteKidneyInjuryNetwork

(AKIN).4

Material

and

methods

Inthisstudyoftheprospectivecohort,18year-oldpatients

admittedtotheICUoftheGeneralHospitalinMexicowere

included, from April 2013 toOctober 2014. Patientswith

chronicrenaldiseasewereexcluded.

Demographic information (age, genre), clinical data

(urineoutputperhourbykilogramandcreatinine),presence

ofcomorbidities(sepsis,shock,multipleorgandysfunction

syndrome(MODS))werecollected.TheScaleforthe

Assess-mentofPositiveSymptoms(SAPS3(severityofthedisease)),

modiﬁed Brussels scale (organic failure)and Nine

Equiva-lentsnursingManpoweruseScore(NEMS(useofresources))

wereassessed.10---12_The_use_of_resources_(invasive

mechani-calventilation,continuousdruginfusions,bloodderivatives,

length of stay in the ICU and hospital stay) were

recorded.

The ARF wasdeﬁned as the stage 1 of the AKIN

clas-siﬁcation, creatinine increase >0.3mg/dL or 1.5---2 times

increaseinbasalvalue,urineoutput<0.5mL/Kg/hpersix

hours4_.

Sepsiswasdeﬁnedasthepresenceofinfectiontogether

with systemic manifestations (temperature >38.3◦C or

<36◦C,heartrate>90heartbeatsperminute,tachypnoea,

leukocytes >12,000/␮L or <4000/␮L, systolic blood

pres-sure <90Torr). Severe sepsis such as low blood perfusion

inducedbysepsisororganicdysfunction(hyperlactataemia,

PaO2/FiO2 <300, urine output <0.5mL/Kg/h, creatinine

>2mg/dL,bilirrubine>2mg/dL,platelets<100,000/␮L).13

Multipleorgandysfunctionsyndrome(MODS)wasdeﬁned

astheprogressivedysfunctionoftwoormorephysiological

systemsconsidered asthe sumof 6or more pointsinthe

modiﬁedBrusselsscale.11

Patientsweredividedintofourgroups.GroupA,patients

whodidnotshowARF;groupB,patientswhoalreadyhad

ARF at the admission to the ICU; group C, patients who

developedARF duringtheir stay at theICU; andgroup D,

patientswhowereadmittedwithARFwhich wasresolved

duringtheirstay anddevelopedagainin thesamestay at

the ICU. Descriptive statistics: Frequencies, proportions,

arithmetical means, standard deviations and cumulative

incidenceofARF.Inferentialstatistics:2-wayANOVA

(anal-ysisofvariance) testfor thedimensionalvariables and2

for non-parametric variables, considering a p value <0.05

signiﬁcant.ThestatisticalpackageusedwastheSPSSv.13

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Table1 Comparisonamonggroups.

VARIABLE GROUPA GROUPB GROUPC GROUPD p

Patients,% 145(40.3) 109(30.3) 73(20.3) 33(9.2) 0.648

Men,% 74(51.0) 54(49.5) 40(54.8) 14(42.4) <0.001

Age,years 43.7±17.0 50.8±16.3 49.8±17.0 54.4±15.7 <0.001

Surgicalpatients,% 70(48.6) 32(29.4) 27(37.0) 5(15.2) <0.001

SAPS3classiﬁcation,scores 45.4±15.7 57.7±16.7 53.8±14.8 59.9±15.2 <0.001

Predictedmortality,% 24.0 44.2 35.5 46.6 <0.001

Observedmortality,% 18.6 56.0 52.1 72.7 <0.001

Attributablemortality,% NA 11.8 16.6 26.1 <0.001

Results

Duringthestudyperiod,400patientswereincludedinthe cohort;31ofthemwereexcludedbecausetheyhadchronic renaldiseaseand9becausetheydidnothavefull informa-tion.360casesremainedfortheanalysis.

Of the360 patients,182 (50.5%) weremen.The mean age was 49 years. The information by groups is found in

Table 1. Patients with ARF during admission to the ICU,

solvedanddevelopeditagainduringtheirstayinICU,were

theoldestpatients,generallycamefrommedicalareasand

showedahigherseverityofthedisease(p<0.001,forallthe

variables).Theprogressivegradientofattributable

mortal-itybetweengroupsfrom11.8%ingroupBto26.1%ingroup

Dstandsout.

TheARFincidencevariedaccordingtothegroupand

cri-terionused.Thegroupincidenceswere30.3%forgroupB,

20.3%forgroupCand9.2%forgroupD.Therefore,the

high-est incidences were found when the uresis criterion was

used.Thelowestincidenceswereobtainedwhenuresisand

creatininecriteriawererequired(Table2).

The main comorbidities were diabetes mellitus type 2

and hypertension, with no signiﬁcant difference among

groups.However,ahypertensiongradientwasfoundamong

groups. There were no documented differences among

groups regarding the presence and origin of infections

(Table 3). However, the presence of sepsis, shock, MODS

andthe use ofvasopressors at admission werefrequently

foundfromgroupsAtoD(p>0.001),theseconditions

hav-ingadeleteriouseffectof onrenal function.The relative

risksof thepresenceofsepsis,shockandMODS on

admis-siontotheICUwereassociatedwiththeARFdevelopment

duringthestay in theICU, and werethefollowing: 1.176

(CI95%1.051---1.316),1.441(CI95%1.159---17.91)and1.376

(CI95%1.023---1.851),respectively.Thenephrotoxicagents

weremoreusedingroupsCandD(p<0.001),whereasthe

vasoactiveswere more usedin groups Band D. Similarly,

sepsis,shockandMODSdevelopedduringthestayintheICU

werecommonlyrelatedtotheARFfromgroupAtogroupD.

AhighernumberofdaysofMODSwerealsodocumentedas

itprogressedfromgroupAtogroupD(p<0.001)(Table4).

Inaddition,patients required ahigher numberof vital

support elements if they had ARF onadmission and then

developeditin theICU,orin casebothevents tookplace

(Table5)(p<0.001,forallthecases).Thisisalsoreﬂectedin

thelengthofstayintheICUandthehospital,andtheuseof

resourcesassessedbytheNEMSscore(p<0.001)(Table6).

Discussion

Thisis theﬁrstARFstudyofMexicancriticalpatientsthat

presentsitsincidenceusingtheAKINgroup’sdeﬁnition.Itis

alsotheﬁrstonetostudytherisk factors,medical

conse-quencesanduseofresourcesinthispopulation.

The ARF incidences vary according to whether it is

present onadmissiontotheICU andthenisresolved,ifit

is developedduringthestay inthe ICUor itis presenton

admission tothe ICU, or it is resolvedand then develops

againandthisiscorrelatedtomorbidity,mortalityandthe

useofresources.Therefore,whenperformingstudiesofthis

condition, thetimeof presentationshouldbeconsidered.

Thus, inthis study,theARF wasmorecommon on

admis-siontotheICU,thentheonedevelopedduringthestayand,

ﬁnally,theonepresentattheadmission,whichwasresolved

andthenappearedagain.Thishasalreadybeenmentioned

byourgroup.9

The incidencesreported inthe threegroups arefound

within intervals reported in literature which generally

consider only the ARF developed in the ICU, reporting

10.1---69.5%rates,accordingtothescaleusedandstage.14---17

As Salgadoetal. have reported,the uresiscriterion is

moresensitivethan thecreatinine criteriontodeﬁneARF,

asfoundinthisstudy.14

Similarly,Levietal.reportedthatpatientsfrom

medi-calareasshowedmoreARFcasesthansurgicalpatients.In

addition,olderpatientswerefoundingroupsBandD,those

whohadARFonadmissiontotheICU,regardlessofwhether

itwasresolvedanddevelopedagain.16

Table2 UsedcriteriatodeﬁneARFbygroups.

Uresiscriterion,% NA 68(62.4) 38(52.1) 17(51.5) <0.001

Creatininecriterion,% NA 44(40.4) 26(35.6) 13(39.4)

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Table3 ARFriskfactors.

Hypertension,% 18(12.4) 24(22.0) 15(20.5) 10(30.3) 0.053

Diabetesmellitus,% 21(14.5) 24(22.0) 18(24.7) 7(21.2) 0.254

Hospital-acquiredinfection,% 15(10.3) 12(11.0) 8(11.0) 5(15.2) 0.888

Respiratoryinfection,% 69(47.6) 56(51.4) 44(60.3) 21(63.6) 0.182

Sepsisattheadmission,% 92(63.4) 90(82.6) 59(80.8) 29(87.9) <0.001 Shockattheadmission,% 45(31.0) 59(54.1) 42(57.5) 19(57.6) <0.001 MODSattheadmission,% 24(16.6) 52(47.7) 27(37.0) 16(48.5) <0.001

VasoactivebeforeICU,% 20(13.8) 35(32.1) 16(21.9) 9(27.3) 0.006

Nephrotoxics,number 0.9±1.0 1.3±0.9 1.4±1.0 1.6±1.2 <0.001

Table4 ComorbiditiesdevelopedduringthestayintheICU.

Sepsisduringstay,% 25(17.2) 28(25.7) 16(21.9) 22(66.7) <0.001

Shockduringstay,% 29(20.0) 24(22.0) 21(28.8) 22(66.7) <0.001

MODSduringstay,% 16(11.0) 21(19.3) 26(35.6) 17(51.5) <0.001

MODS,days 1.4±3.8 2.7±3.6 3.2±4.8 7.3±7.6 <0.001

Table5 Useofresources.

Mechanicalventilation,days 10.3±13.1 7.5±10.8 8.6±8.7 14.6±13.3 <0.001

Dialysis,% NA 4(3.7) 0(0.0) 1(3.0) NS

Antibiotics,number 1.9±2.0 2.3±1.9 2.8±2.2 4.5±2.8 <0.001

Druginfusions,number 1.8_±2.0 3.1_±2.5 3.7_±2.2 5.1_±2.8 <0.001

Bloodcomponents,number 0.2±0.5 0.3±0.6 0.3±0.5 0.7±0.9 <0.001 StayintheICU,days 7.2_±9.5 7.5_±10.3 9.8_±8.4 18.3_±13.9 <0.001 Lengthofhospitalstay,days 27.2±20.6 17.3±15.3 20.9±12.2 29.8±26.8 <0.001 NEMS,points 172.5_±281.4 199.1_±289.1 272.1_±266.4 510.8_±404.9 <0.001

Table6 NEMSscale.

ITEM POINTS

1 Basicmonitoring:hourlyvitalsigns,regularregisterandestimateofliquidbalance 9 2 Intravenousmedications:bolusorcontinuousinfusion,vasoactivedrugsarenotincluded. 6 3 Mechanicalventilatorysupport:anyformofmechanical/assistedventilation,withorwithoutpositiveand

expiratorypressure(PEEP),withorwithoutmusclerelaxants

12 4 Supplementaryventilatorycare:spontaneousrespirationbyendotrachealcannula;anyformof

supplementaryoxygen,withtheexceptionoftheitemthreeapplication

3

5 Uniquevasoactivemedication:anyvasoactivedrug 7

6 Multiplevasoactivemedications:morethanonevasoactivedrug,regardlessofthetypeanddose 12

7 Dialysistechniques:all 6

8 SpeciﬁcinterventionsintheICU:suchasendotrachealintubation,pacemakerinstallation,cardioversion, endoscopy,emergencysurgeryinthelast24hours,gastriclavage;routineproceduressuchasX-rays, echocardiogram,electrocardiogram,placementofvenousorarterialcathetersarenotincluded

5

9 SpeciﬁcinterventionsoutsidetheICU:suchasasurgicalinterventionordiagnosticprocedure:the intervention/procedureisrelatedtotheseverityofthediseaseandproducesanextrademandonthe workloadoftheICUstaff

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Regardingtheriskfactors,thesamefactorsasthosein international literature were found.16,18 _Sepsis _and _shock

continuebeingthemainriskfactorsforARFdevelopment.

Atthesametime,themanagementoftheseclinical

condi-tionsrequires agreater use ofvasoactivesand drugsthat

turntobenephrotoxic,favouring thepersistenceofrenal

damage,aspreviouslyreported.9

ARFdevelopmentisanindependentmortalitypredictor,

increasingfrom 18.6% without ARFto 72.7% whentwo or

moreARF events occur onadmission andthen duringthe

stayintheICU.However,mortalitywaslowerthanreported

intheliterature;itreachedupto50%insomeseries.14,19_In

thisway,themortalityattributabletoARFonadmissionwas

11.8%,butincreasedto26.1%whenthereweretwoormore

ARFeventsfromadmissiontotheICU.

The mechanism by which the ARF contributes to the

increaseinmortalityisnotcompletelyunderstood,butthe

volumeoverload,coagulationanomaliesandagreater

inci-denceofsepsisandmultipleorganfailureplayanimportant

role.20---25

Theuseofresourcesevidentlyincreaseswhenapatient

developsARF.9_In_the_present_study,_greater_use_of

mechan-ical ventilatory support, use of drug infusions, blood

componentsandantibioticswasdocumented,whichledtoa

longerstayintheICUandthehospital.Themeasurementof

theuseofresourcesthroughtheNEMSscaleshowedan

out-putgreaterthandoubleinthepresenceofARF.TheNEMS

scale is equivalentto the Therapeutic Intervention Score

System(TISS)anditsusefulnessistoclassifypatientsinto4

classestoassignnursesto:ClassI<10points,patientswhodo

notneedUTI;ClassII10---19points,1:2nurse---patient

rela-tion;ClassIII20---39points,1:1nurse---patientrelation;and

ClassIV≥40points,2:1relation,twonursesperpatient.26

Study limitations.The natureof auniquecentre limits

generalisation,andthedesignof arelativelysmallcohort

doesnotallowtheassessmentofothercontributoryfactors

ofprognosticimportance.

However,thepresentstudycharacterisestheincidence,

risk factors and impacton the ARF regarding health, life

anduse of resources, using the most recent standardised

deﬁnitionwhichsimultaneously usesthe serumcreatinine

andurinaryoutputcriteria.

Funding

None.

Conﬂict

of

interests

Theauthorsdeclarenottohaveanyconﬂictofinterestin

theelaborationofthiswork.

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