determinants of health care costs of hiv-positive patients in the canary islands, spain

8/12/2019 Determinants of Health Care Costs of HIV-Positive Patients in the Canary Islands, Spain

1/9

Determinants of health care costs of HIV-positive patients in the Canary Islands, SpainAuthor(s): Juan Oliva-Moreno, Julio Lpez-Bastida, Pedro Serrano-Aguilar and LilisbethPerestelo-PrezSource: The European Journal of Health Economics, Vol. 11, No. 4 (August 2010), pp. 405-412Published by: SpringerStable URL: http://www.jstor.org/stable/40730775 .Accessed: 27/03/2014 07:14

Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jsp

.JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact [email protected].

.

Springer is collaborating with JSTOR to digitize, preserve and extend access to The European Journal of Health Economics.

http://www.jstor.org
http://www.jstor.org/action/showPublisher?publisherCode=springerhttp://www.jstor.org/stable/40730775?origin=JSTOR-pdfhttp://www.jstor.org/page/info/about/policies/terms.jsphttp://www.jstor.org/page/info/about/policies/terms.jsphttp://www.jstor.org/stable/40730775?origin=JSTOR-pdfhttp://www.jstor.org/action/showPublisher?publisherCode=springer


2/9

EurJ Health con 2010)11:405-412DOI 10.1007/sl0198-009-0212-z

ORIGINAL PAPER

Determinants f health care costsof HIV-positive atientsin the Canary slands,SpainJuan Oliva-MorenoJulio Lpez-BastidaPedroSerrano-AguilarLilisbethPerestelo-Prez

Received: 7April 008Accepted:December009 ublishednline: January010Springer-erlag 009

Abstract The aimsofthis tudy ere o estimatemedicalexpendituresn human mmunodeficiencyirus HIV)treatment nd to identify ignificantssociatedvariables.We performed retrospective ulti-centretudy n theCanaryslandsusing sample f 569patients ecruitedtoutpatient isits.The study xamineddemographicndclinicalvariables, ealth-relateduality f ife HRQOL),andhealth are resources. linical data wasobtained rommedical ecords ndpatient nterviews.everalempiricalmodels ordentifyinghe elationshipetween ealth arecosts and independent ariables were developed.Thegreatest xpensecamefrom harmaceuticalxpenditure

J.Oliva-MorenoDepartmentf EconomicnalysisndFinances,Universityf Castilla a ManchaUCLM),Toledo,pain

J.Oliva-MorenoCIBERESP-CIBER nEpidemiologyndPublicHealth,Toledo,pain

J.Lpez-BastidaP. Serrano-AguilarL. Perestelo-PrezCIBERESP-CIBERnEpidemiologyndPublicHealth,antaCruzdeTenerife,pain

J.Lpez-BastidaP. Serrano-AguilarL. Perestelo-PrezEvaluationndPlanningervice, anaryslands ealth ervice

(SCS),SantaCruzdeTenerife,paine-maillperperrgobiernodecanarias.org

J.Lpez-BastidaUniversityospital uestraenora e la Candelria,CanaryslandsHealthervice,antaCruzdeTenerife,pain

J.Oliva-MorenoE3)Facultad eCincias urdicasSocialesde ToledoAnlisisEconmicoFinanzas obertizoe San PedroMrtir/n,Toledo,spanae-mail: [email protected]

(82.1%of direct osts),whilehospital ostsonly repre-sented .6% of total xpenditure.he data showed sta-tistically ignificantssociation etween ealth are costsand theCD4 count f theprevious ear.HRQOLwas alsoa significant ariable.Therefore, D4 cell count an beused topredict ealth are costs n patients. olicymakerscould use this nformationohelpguide heir ecisions nallocatingimited ealth are resources oHIVtreatments.

Keywords HIV/AIDS Health are costsHealth-relateduality f ife Observationalmulti-centretudy

Introduction

Since itsdiscoveryt the beginning f the 1980s,humanimmunodeficiencyirus HIV)has become one of thegreatest ealth hallengesn the world 15].HIV/AIDSplacesanever ncreasing urden n the population'stateof health s well as contributingosignificantocio-eco-nomic difficulties or ndividuals, amilies, ommunitiesandgovernmentsn many ountries8,51].

The argenumber f ases andthehigh ost f providingservicesrelated to HIV infection s a majorconcern

addressed y health olicy n countries cross the globe,regardless f their conomic tatus. pain is amongthecountries ith hehighest IDS incidenceatesnWesternEurope 51]-almost .2 casesper 100,000nhabitantsn2005, after adjustingfor reporting elays. Since thebeginning f the AIDSepidemic, totalof 72,099newAIDS cases havebeenreportedn Spain,with he numberofdeaths angingetween 0,000 nd55,000.EventhoughSpaindoesnot have an official egister orHIVpositivecases, he revalencefHIV-infectedeoplewasestimated

4ySpringer

This content downloaded from 103 .24.98.179 on Thu, 27 Mar 20 14 07:14:12 AMAll use subject to JSTOR Terms and Conditions
http://www.jstor.org/page/info/about/policies/terms.jsphttp://www.jstor.org/page/info/about/policies/terms.jsphttp://www.jstor.org/page/info/about/policies/terms.jsp


3/9

406 J.Oliva-Morenot al.

to range between 2.4 and 3.6 per 1,000inhabitants(120,000-150,000eople)11, 45].

Advances n medicineaveyet o find definitive urefor HIV/ IDS, althoughnew therapies ranging rom

zidovudinemonotherapyo highly ctive antiretroviraltreatmentHAART) haverepresented new era n ther-apeuticmanagementhat as ncreasedife xpectancyateand offered mprovementn the quality f life of HIV-patients 2, 24].The highcost of such therapiesmakesmeasuring ealth are costs and breaking hem ownbytype of treatment r services xtremely mportant. orinstance,t is not clear whether heHAARTtherapy asincreased he annual treatment ost per patient 4, 50],althought seems that he ifetime ealth are costs forpatients re muchhigher,which s due primarily o theincreasedife xpectancyf HIV+patients. n the otherhand, t s clear hat hedistributionfhealth are pending

has changed s a result f the ntroduction f new pre-scription rugs 6-8, 17, 33, 42, 46, 49, 50], with anincrease n the ratio of pharmaceuticalxpendituresocosts ssociatedwith npatientare.

In spite f Spain'srelatively igh HIVrate, here avebeenno recent tudies n HIV-relatedosts.The aim of hepresent tudy was to calculate he otal nnualhealth arecosts fpeopleivingwith IV/ IDS inSpain, swell s toprovide breakdown f spending n the followingtems:hospital dmissions,utpatient isits, ests, ehabilitationservices, mergencyervices nd drugs. n addition,weaimed o dentifyignificantariablesssociated ith ealthcare osts hatmight elppredict osts n HIVpatients.

Methods

Study esign

A cross-sectional,etrospectivetudy f peoplediagnosedwithHIV/AIDSreceiving utpatient arewas conducted.Patients ererecruitedccordingo diseaseseverity romfour ospitalutpatientlinicsn theCanaryslands, pain.The1993classificationcheme roposed ytheCentre orDiseaseControlndPreventionCDC)in heUnited tates odivide hediseasentoHIV-asymptomatic,IV-symptom-atic ndAIDSstages1]was used o stablishhe everityfHIV infection.ll patients ere nformedbout he tudyobjectivesnd he onfidentialityf he ata ndwere skedto how heir greement ith, nd heir nderstandingf, hestudy onditionsy signing declarationf consent orm.Thestudy asapprovedy he thics esearchommitteefUniversity ospitalNuestra ra. de la Candelria.Thefieldwork as carried utbetween anuaryndDecember2003.Demographicnd clinicaldata werecollectedforpeoplepreviouslyiagnosedwithHIV/ IDS.Thepatients

recruited ere t east 1 years ldand were reatednout-patient linics.ncarceratedIVpatients erenot ncludedin the nalysis. lso, omepatients ere xcluded rom hefinal nalysisf he nformationathered as ncomplete.

A total f569

medical ecords romIV+

adultatientswere eviewed.ased on dataprovidedyCastilla ndde a

Fuente 11],weestimatedhat he ample izerepresented23% of allpeoplewithHIV/AIDSn theCanaryslands.Medicalrecords ereusedto obtain ata onage, agewhenHIV transmissionasconfirmed,ender, ost ikely auseoftransmissionndCD4 cell countor he urrent ndpre-viousyear CD4+countswithin ells mm 3). n addition,patients ere sked ofill ut he eneraluestionnaire,Q-5D [48].The EQ-5Didentifies ive health categories:mobility, elf-care, sualactivities, ain/discomfort,ndanxiety/depression,nd three egrees o describe tate fhealth: oproblems,mildproblems nd severe roblems.

Additionalnformationbout he seofhealth are esources(emergencies,ehabilitationsnd outpatient isits)wasobtained rom specificuestionnaire.

Costs

We estimated ealth are costs from NationalHealthSystem perspective, ollowing bottom-up pproach,assigningmonetaryalue o hehealth areresources sedby eachpatient n a case-by-case asis.All costs areexpressedn Euros n the base year 2003).Informationabout henumber f hospital dmissions,ests nd use ofprescriptionrugs or roblemselated oHIV/ IDSinthe

1 months rior o henterview ere btained rommedicalrecords. nit ostswere btained rom numberf ources.The costof npatientarewas based onDiagnosisRelatedGroupsDRGs)publicprices. he unit osts for estswereobtained irectly rom ospitalsn theCanaryslands. rugcostswere alculated asedon the fficial elling rices ohospitals n the Canary slands.Additionalnformationabout heuseofhealth are resources asobtained romspecific uestionnaire.nformation btained rom ues-tionnairesompleted yHIV+patients as usedto deter-mine henumberf mergencies,ehabilitationessionsndoutpatientisits elated oHIV/AIDS.Theaverageost fsingle mergency isit, ehabilitationession ndmedical

appointment ere obtained rom he SOIKOShealthcareunit ostdatabase44].This s themost omplete atabaseavailablenSpainfor ealth areunit osts.The sources fthe unit costs are published rticles, eports, ospitalaccountingystems,tc.Thefiguresreupdatedvery ear.

Analytical ramework

Ordinaryeast quares egression as usedto estimate hedeterminantsf annual osts.We usedthe Eicker-White

Springer



4/9

Determinantsf health are osts f HIV-positiveatients 407

covariancematrix stimator 19],so that nference s validinthegeneral ase where hevariance f the rror erm snot constant cross respondents.We used a range ofbetween 19and545validcases for he nalysis.

Models1,2 and3 used he amedependent

ariable:hedirect ealth are ost.Model1has a number f exogenousvariables:ge,age-squared, ender, ime incediagnosis,most ikelycause of transmissionnd CD4 cell count12 months eforenterviewlow CD4^1< 200);medium(200< CD4/[d 500)andhigh CD4/f 500)].Model2 incorporateshehospitalwhere hepatient eceived is/her reatments anexplanatoryariable. hisvariablewasincluded s a means ocontrol otential eterogeneitynclinical racticemong ifferententres.We addedhealth-related uality f ife HRQOL; EQ-5D)as an ndependentvariablen Model 3.In the face of potential ollinearityproblemsetween heobjective ealth ariablesCD4cell

count)nd the

self-perceivedRQOLlevels,a seriesof

Spearmanestswasperformedn the objective nd sub-jectivevariables elating o state f health. Although heresultswere n line withwhatwasexpectedtherewas astatisticallyignificantelationshipetween D4count ndquality f ife), he orrelationoefficient as ow. Forthisreason, oth re ncluded imultaneouslyn Model 3. Wealso testedModel 3 for roblemsf multi-collinearity.hevariance nflationactornd tolerance ere used to assesspotentialmulti-collinearityfor moredetails, eeGreene)[19].The values obtainedwere locatedbelow criticalvalues.

Models4 and 5 are identical o Model2 and 3,

respectively,nsofar s the independent ariablesused.However,here ere ifferences or hedependentariabledrugs osts Model 4).Weanalysedhis tem ecause t

representshegreatest ortion f health are costs.

Results

The average age of the samplegroupof patientswas40.6years, ndthe verage geat whichHIVtransmissionwas confirmedas 32.7. Oursample roupwascomprisedmostly f males 84.2%).The most ikely ause oftrans-missionwashomo/bisexualontact 46.4%),following yheterosexualontact 20.0%)and intravenous rug use(19.9%).Themost ikely ause of transmission as notprovidedunknown)y 12.8% of thepatients uestioned.Informationbout CD4 cell countwas obtainedfor aperiodbeforedata collectionhad begun.Patientsweredivided nto three groupsbased on their CD4 count:lowCD4 cellcount CD4/'d< 200),mediumCD4 cellcount 200< 4/1 500),and high CD4cell count(4/1 500).Twelvemonths efore he nterviewyear2002),theCD4 countor 0.5% ofthepatients uestioned

waslow,35.6% had a medium D4count, nd53.9%hada high ount. he average isual nalog cale VAS)scoreforHRQOLwas 0.7581 out of 1. Theaverage ime rade-off (TTO)score for HRQOLwas, 0.8104out of 1(Table 1).

Averagehealth are costs were8,231perpatient SD4,291).The most mportanttem n health are costs wasdrugs osts,with n averagevalue of6,752SD 3,031).The secondhighest osts weretests,with n average f740 SD 359).Differencesncostbystage f disease relisted n Table 2 and llustratedn Fig.1.

The results f the tatistical odels how hat ime incediagnosisyear 003 minus heyearwhenHIV transmissionwasdiagnosed), D4 cell count 12 months efore nter-view,HRQOL,and the hospital re significant ariablesthat elp xplain ealth areexpenditureModels 1-3).Onthe other hand, age, gender nd most likelycause oftransmissiono not

ppearobe

significantariables.When

explaininghe xpenditureor rescriptionrugsModelsand 5), time sincediagnosis, D4 cell count12monthsbefore nterview, RQOLand hospitalare significantvariables. n all the regressions erformedTable 3),the

Table1 Descriptionf ndependentariables AverageSD)/%

Age nDecember 003 569 40.68.2)Time inceHIVdiagnosisyears) 569 7.9 4.7)Gender 569

Males 84.2%Females 15.8%

Hospital 569Hospital 21.1%Hospital 20.2%Hospital 34.3%Hospital 24.4%

Mostikelymode f transmission/riskroup569Intravenousrug se 19.9%Homo/bisexualransmission 46.4%Heterosexualransmission 20.0%Otherspatients ith aemophiliand 13.7%unknown)

CD4 count n t-' 545500(high) 53.9%

Health-relatedOLamong urviving 538patientsEQ-5D)TTO score 0.81040.2465)VAS score 0.77650.2132)

HIV Humanmmunodeficiencyirus, OLQualityf ife, ASisualanalogcale,TTO timerade-off

Springer



5/9

408 J. Oliva-Morenot al.

Table2 Health are osts y tage f diseaseAllpatientsN= 569) AverageSD MinimumMaximumType f expenditureMedicalisits 296 230 0 1,634Emergencyare 59 173 0 1,960Rehabilitation 1.43 16.4 0 258Tests 740 359 0 2,701Drugs 6,752 3,031 0 18,238Hospitaldmissions 382 2,330 0 32,136Totalhealthxpenditure8,231 4,291 280 41,637Asymptomaticatients

(N= 268)Medicalisits 241 143 0 1,158Emergencyare 45 179 0 1,960Rehabilitation 0.5 5.9 0 86Tests 645 253 0 2,318Drugs 6,184 3,054 0 14,792Hospitaldmissions 26 422 0 6,909Totalhealthxpenditure7,140 3,218 310 16,579Symptomaticatients

(N= 141)Medicalisits 329 250 78 1,404Emergencyare 50 113 0 686Rehabilitation 0 0 0 0Tests 792 348 120 2,031Drugs 7,040 3,126 0 18,238Hospitaldmissions 264 1,217 0 6,909Totalhealthxpenditure8,475 3,751 280 20,600AIDSpatientsN= 160)

Medicalisits 359 299 44 1,634Emergencyare 90 201 0 1,176Rehabilitation 4,3 29,8 0 258Tests 854 464 56 2,701Drugs 7,451 2,727 0 16,101Hospitaldmissions 1,084 4,131 0 32,136Totalhealthxpenditure9,842 5,599 783 41,637Valuesn 2003Euros

Snedecor is higher han hecritical alueand,conse-quently,xplanatoryariablesre ointly ignificant.

The results f Models1 and2 can becompared ith he

results f Model 3, and the results f Model4 can becomparedwith he results f Model 5. In Model3, webeganwith basecasehaving nannual ealth are ostof5,757.Age,gender nd mode of transmission erenotstatistically ignificant ariables.On the contrary, hehealth are osts or personwith low CD4count uringyear - 1are4,365 igherhe ollowing eart)comparedto a personwith highCD4count uring ear -l. WithmediumCD4count 200< CDAI'< 500),health areexpensewill ncrease y 1,046 n yeart comparedoa

patient ith highCD4count uringheprevious ear.Asfor time variables, ach additional earsincediagnosismeans n additional 106 pent n health are.HRQOLisinversely elatedo health arecosts thebetter he ualityof

ife,he essthehealth-care

osts).or nstance,

personwith lowHRQOL(TTOscores ower han .75)costs1,376more han personwith highHRQOL(TTOscorehigher han0.75).Finally, hereweresignificant iffer-encesin the cost of treatment mong hefourhospitalsincludednthis tudy. ospital had a significantlyighercostperpatient1,670)hanHospital (when herest ffactorswere controlled). ospital2 had a significantlylower ostperpatient 1,086)hanHospital . Hospitaldid notpresent ignificantifferencesn costswhen om-pared oHospital .

InModel5,webeganwith basecasein which nnualspendingn pharmaceuticalseached5,205.Age, gender

andmodeoftransmission erenot ignificantxplanatoryvariablesor rugs osts.Onthe ontrary,or personwitha low CD4count uring ear - 1,thedrugs ostswill be1,592nthe ollowing eriod omparedo apersonwithhigh CD4 count n t-l. With a mediumCD4 count(200< 4/1 500),health areexpensewillincreaseby571during he period s comparedo apatient ithhighCD4countduring heprevious eriod.As regardstime ariables,achadditional ear rom ime f diagnosismeans n additional 132expense n drugs. heHRQOLis inversely roportionalothe osts onprescriptionrugs(thebetter hequality f ife, he essthe drugs osts).Apersonwith low HRQOL(TTOscoresower han .75)

incurs costwhichs 488higherhan personwith highHRQOL(TTOscorehigher han .75).Finally, hereweresignificantifferencesndrugs ostsperpatient t the ourhospitals nderconsideration. ospital3 had a signifi-cantly igher ostof drugs er patient f 749 thanHos-pital (when herest f factors ere ontrolled). ospital2 had a significantlyowerpharmaceuticalostperpatient(1,001)hanHospital4. Hospital1 hadpharmaceuticalcosts hatwere omparableothose t Hospital .

Discussionnd conclusions

Internationalourcesdocumenting IV/ IDSshowthathealth arecostsvarygreatly rom ountry ocountry. tthepresent ime, owever,t s not lear f the nnual ostof reatmenterpatient as ncreasedince he ntroductionofHAART.Theresagreementn the iterature hat nnualantiretroviralrug ostshave ncreased, ut somestudieshavefound hat his act s balanced ya reductionn theannual ostsof inpatient, utpatient nd evenhomecarecosts.There s less doubt hat, n a lifetime ontext, heoverall ostoftreating HIVpatient asclearlyncreased

Springer



6/9

Determinantsf health are osts f HIV-positiveatients 409

Fig.1 Distributionf healthcare osts y tage f disease

incomparison ith he arly 990s.Thismaybeexplainedby the fact hat HIVpatients ive with nd require reat-ment or he virus or pproximately0 years 3-5,10, 12,16, 18, 20, 21, 23, 25-30, 32-34, 37, 39, 41, 45, 47,50].

In Spain,our data for nnual reatmentosts re owerthan he osts previouslyeported y Antonanzas t al. [3]andMompoet al. [34].A possible explanationor thisdifference ight e the ncrease n thenumber f patientswith he dvanced isease AIDS)since earlier tudies nSpain,which adfarfewerAIDSpatientsn their amplegroups.We have ried o ncrease he eliabilityf ourdataby recruiting larger ample f HIV-positive atients ith

a samplegroupdistributionimilar o that f the AIDSpatients n the population.The international rendofreducingheuse of npatientervices rom 995 to 2003 ssimilarlybservednour tudy. ntonanzast al. [3]foundthat 5% of total ealth are costsfor eropositiveatientswere for he use of inpatient ervices, nd antiretroviraltherapy epresentednly .7%. Ourmore ecent ata howa dramaticncrease ndrugs osts more han 0%oftotalhealth are costs)and a reductionn other tems. y con-trast, ospital dmissions re the third mostcostly tem,with n average ost of 382. n fact, nly the 4.2% ofpatientsncludedn our amplewere dmitted ohospitalnthe 12months rior othe nterview.

Our datasuggest hat, fter year, patient ith lowCD4 cell countwill incur4,300^,600more n healthcare-relatedxpenses hanpatientswithhigher D4 cellcounts, ue to the needformore xpensivemedicationseeModel5) and intensive se of additionalhealth careresources.n sum,we found hat low CD4 cell counts agoodpredictor f intensive ealth are utilisationmoreexpensive rugs nd npatientervices)hefollowing ear.These esults re n inewith revious indingsrom rentzet al. [30]for late presenters . atients' ge, gender nd

mode of transmission re not significant ariablesforexplainingosts. nthe ase of ge,this s no surprise.essthan % of the tudy amples older han 0 years f age,andthemajority f he atients recloser o40.Contraryoother tudies 12],we have notdiscoverednydifferencesincostbysex dueto ntolerancend adverse ffects). hesimilarity etween hefigures ormen and womenwouldalsosuggest hat here re no gender nequalitiesnaccessto treatment. his finding lso hints hat there re noinequalitiesn access to treatment ased on the differentrisk actors nvolved n the ransmissionf thedisease.

The Canary Islands Health Service consider that

informationn HRQOL,together ith ther nformationsources such as epidemiologicaland socioeconomicinformation, lays a key role in priority etting ndresource llocation etween ifferent ealthproblemsnthehealth are planning10].Inrecent ecades, uality flife has increased n importance s a key health tatusindicator. s Sullivan47]notes, Medicine'sepidemio-logicaltransition rom cute to chronic disease is thusprompting n epistemologicalransition rom primarilyobjective oprimarily ubjective videnceof health ndhealth are effectiveness.ow someof the most mportantpatient utcomes,ike patient hoicesbefore hem, revalid becausethey are subjective .Additionally,ome

studies eveal thatbad HRQOLis associatedwithhighmortality22,25, 28, 39,40]and a greater se ofhealth-careservices13,40,43].Arelevant esult f this tudy sthat, fter djusting or significantlinicalvariable uchas CD4 cellcount,HRQOLis inversely nd significantlyassociatedwith health care expenditure. lthough hisresult eems to associateHRQOLwithhealth are costs,onemust e careful hen ttributingoincidentalffects othis variable. Morespecifically, he nature f the data(a cross-section)equires aution o be exercised efore

Springer



7/9

410 JOliva-Morenot al.

Table 3 Determinantsf health are ostsHealth are Health are Healthare Costs f Costs fcosts costs costs drugs drugsModel1 Model2 Model3 Model Model5

Time ince iagnosisyears) 112.51** 100.82** 105.86** 130.63** 132.23**(39.59) (40.33) (42.23) (27.88) (29.32)

Low CD4countCD4< 200)inpreviousear 4,327.08** 4,623.96** 4,364.57** 1,773.79** 1,591.67**(1093.36) (1072.91) (1144.21) (449.15) (474.83)

MediumD4 count200< CD4< 500)npreviousear 837.13** 1,133.92** 1,045.55** 639.78** 570.87**(322.15) (323.40) (330.25) (261.86) (271.30)

EQ-5DTTO) -2,650.13** -877.56*(760.02) (477.84)

Hospital -1,006.30** -1,085.88** -1,012.17** -1,001.32**(466.99) (482.96) (360.04) (380.55)

Hospital 1,698.71** 1,669.93** 697.31** 749.28**(454.97) (453.10) (325.39) (331.14)

Intercept 2,999.38 3,651.25* 5,757.34** 4,273.46** 5,205.36**(2,283.20) (2,168.41) (2,201.47) (1,704.32) (1,786.76)

TV 545 545 519 545 519R2 0.1134 0.1721 0.1906 0.1185 0.1207F 4.99 5.83 5.90 5.36 4.77

Values n urosstandardeviationnbrackets).asepatients a malewith high D4 cellount he ear eforehe tudyCD4^1> 500),whowas nfectedhrougheterosexualontactndwasreceivingreatmentt Hospital. Some xplanatoryariables.g.age,gender, ostikelymode f ransmissionnd he ummyariableHospital were ot tatisticallyignificant.heir oefficientsave een xcludedromhe able*Significantariable:I = 90%;**Significantariable: I= 95

attributingcausalrelationship.uture esearchhat elvesfurther nto the relationship etweenHRQOLand costscouldprovide s with urtherupport.

Themulti-centreature four tudy ncreasedeliabilityandenabled s to observe ignificantifferencesn overallcosts mong heparticipatingospitals. hisfactneeds obe considered hen nalysing atacoming rom singlehealth are institution.n fact, n important oint f theanalysis s the inclusion f hospitals s an explanatoryvariable. ospital shows costperpatient 1,670 igherthan hebasehospital Hospital4) after ontrolling orother actors. ospital hasa higher ospitalisationatethan herest, which nfluenceshetotal amount f thecorrespondingosts, nd alsopresents highermedicationexpense erpatient han hehospital sedas areference.tispossiblehat atients reatedn this ospitalre t greater

risk han hosen the other ospitals, ut this s reflectedneither n the socio-demographicariablesage,gender,time since nfection nd causeof infection), or n theclinical istoryCD4count), or n the elf-perceivedtateofhealth, hen he ffects f hese ariablesrecontrolledfor tatistically.

Alsoworth otings thefact hat he ostperpatient tHospital is lower han hebasehospital.n this nstance,comparisonf Models3 and 5 reveals hat he ower ostper patient s due almost ntirely othe owermedication

expense erpatient. number f ausesmight efound orthis ackofhomogeneity.n thefirst lace, heprofilesndrisksof the patients nder reatmentn the four entres

mightdiffer, hichwas not reflected n the variablesanalysed.econdly, ariabilityouldresult rom heuseofdifferent linical racticesn the differententres, ot nlyin the preventionf opportunistnfections,ut lsoin thetypes f ntiretroviralreatmenthosen.t s notpossibleodeterminehese lementswith heavailablenformation,but t would,without oubt, eof nterest oCanaryslanddecision-makersoknowthe cause of thesedifferences.Finally, t should ementionedhat his tudy slimited oanalysinghe osts ssociatedwith he reatmentf HIV+patients.t does not ncludenformationn thequality fthe treatment ach patient eceives.Thiswill remainpending uestion or future esearch n whether igher

costsstemfrom mprovementsn the quality f careorfrom heuseofmore nnovative edicineshat ostmore.Someimitationsf he tudy hould epointed ut. irst

atall,ourresults re imited ythe ype f dataused.Moreprecisely, cross-sectionalurvey s notthe most ppro-priatedesignfor studying ausalrelationships etweenvariables. prospective,ongitudinaltudy ould eamoreappropriateesign or his urpose. his s especiallyele-vant n the tudy f thecause-effectelationshipetweenHRQOLand costs.Secondly,n spiteof lowR2values

Springer



8/9

Determinantsf healthare osts f HIV-positiveatients 411

commonlyoundnempiricalmodelswith ata on ndivid-uals,most f the variance s not xplained ythemodels.Consequently,he esultshould e nterpreted ith aution.Thirdly,moreresearch s neededto explainthe ack of

homogeneityncosts

monghospitalsfter

ontrollingor

other xplanatoryariables.We havenot onsidered ata nintolerancendthe dverse ffects f medications uch stransaminites,epatoxicity,yperglycaemia,ipodystrophy,insulin esistance,ccelerated oneloss,dyslipidaemias,nausea andvomiting, eadache,naemia,depressionndsleepdisturbances20].The clinicalrecords sed did nottreat hese roblemsn a similarmanner,nd t s not lear ffailure o mention hemmeansthose nterviewed id notsuffer dverse ffects r if they houldbe interpretedsmissingalues. inally, e considernly ealth are osts nthe nalysis. owever, hevastmajority f HIV+patientsare f workingge.As severaltudies ave hown 9,14,18,

31, 35, 36,38]CD4 cellcount s a significantariable orexplainingabour articipation.hus,CD4cell countnthet-' periodmight e a significant ariable orpredictinglabour articipationf HIV+patients.

Acknowledgmentshe study enefitedrom he support f theCanaryoundationorHealth ndResearch,FUNCIS)andfrom heSEJ2005-8793-CO4-01-04roject SpanishMinistryf EducationandSciences)nd ECO2008-06395-C05-03/ECONrojectSpanishMinistryfSciences ndTechnology).hisworkwas alsosupportedbyan unrestrictedducationalrant wardedointly o theUniver-sities arlos II of Madrid nd Pompeuabra f BarceloneyTheMerck oundation,hephilanthropicrm f Merck o. Inc.,WhiteHousetation, ewJersey, SA. We want oexpress pecialhankstothe ealth are rovidersnd ther ndividuals ho ollaboratednthis

tudy:r. Gomez irvent .,Dr. Alonso oasM.,Dr. Alemn

VailsM.,Dr. Armas ortelaM.,Dr.Zarzalejos,r. Crdenes,r.FrancesUrmeneta ., Dr. Moreno.,Dr. Linares eriaM.,Dr.MiguelesM.,Dr.HayekM.,Gonzalez arneiro, VelasquezlmosF.,Negrn avarro.,Hernandezethencourt.,Bacallado iazM.,WoodWoodM.,andDubrito aliesA.

References

1.Ancelle-Park,.A.:Expanded uropeanIDS case definition.Lancet41,441 1993)

2. Anis,A.H.,Guh, ., Hogg,R.S., t l.: Thecost-effectivenessfantiretroiral egimensor he reatmentf HIV/ IDS. Pharma-coeconomics8,393^04(2000)

3. Antonanzas-Villar,.,Anton-Botella,.,Juarez-Castello,: Thecalculation f AIDS costs nSpain bysimulationechniques.Med.Clin.Bare)104,568-5721995)

4. Basuyau,., Josset, ., Merle, .,et l.: Casefatalityndhealthcare osts nHIV-infectedatients:volutionrom 992 o2000atRouenUniversityospital,rance.nt.J. TD AIDS15,679-684 2004)

5. Beck,E.J.,Mandalia, .,Gaudreault, ., et al.: Thecost-effec-tiveness f highly ctive ntiretroviralherapy. anada1991-2001.AIDS18,2411-24182004)

6. Beck,E.J.,Mandalia,., Griffith, ., et al.: Use and cost ofhospitalnd ommunityervicerovisionor hildren ith IV

infectiont an English IV referralentre. harmacoeconomics17,53-69 2000)

7. Beck, .J.,Mandalia, ., Williams,, et l.: Decreasedmorbidityanduse ofhospitalervicesnEnglish IV-infectedndividualswithncreasedptakef nti-retroiral herapy996-1997.IDS13,2157-21641999)

8. Beck,E.J.,Miners, .H.,Tolley, .: The cost f HIV treatmentand are.Aglobaleview. harmacoeconomics9,13-392001)9. Bernell, .L.,Shinogle,.A.: herelationshipetween AART

useandemploymentorHIV-positivendividuals:n empiricalanalysisndpolicy utlook. ealth olicy 1,255-2642005)

10.Canary Island Health Programme online].http://www.gobiernodecanarias.org/sanidad/scs/l/plansalud/plansalud2004_2008/ppal.htm.ccessed May2008

11.Castilla, ., e la Fuente,.: Evolucin el nmeroepersonasinfectadasor l virus e la inmunodeficienciaumana de oscasosdesida nEspana:1980-1998.Med.Clin.Bare)115, 5-89(2000)

12.Clark,R.: Sexdifferencesn antiretroviralherapy-associatedintolerancend dverse ffects. rug af.28,1075-10832005)

13.Conelli, .E.,hilbrick,.T., mith, .R., t al.: Health ercep-tions f primaryarepatientsnd the nfluencen health areutilization. ed. Care27,S99-S1091989)14.Dray-Spira,., Lert, ., Marimoutou,, et al.: Socio-economicconditions,ealthtatus nd employmentmong ersonsivingwithHIV/AIDSn France n 2001. AIDS Care15,739-748(2003)

15.Fauci,A.S.:TheAIDSepidemic.onsiderationsor he 21stcentury. .Engl.J.Med.341,1046-10501999)

16.Flori,..,le Vaillant,M.: Use and cost of antiretroirais nFrance 995-2000:n analysisasedon themedical ossier nhuman mmunodeficiencyrelease2) database. harmacoeco-nomics2,1061-10702004)

17.Garattim,., Tediosi, . ,DiCintio, ., et l.: Resourcetilizationandhospitalost f HIV/ IDS care n taly n the ra ofhighlyactive ntiretroviralherapy. IDS Care13,733-7412001)

18.Goldman, .P., Bao, Y.: Effective IV treatment nd theemploymentf HIV(+)adults.Health erv.Res.39(6Pt 1),1691-17122004)19.Greene,W.H.: Econometricnalysis,rd dn.MacMillan,ewYork 2000)

20.Hellinger, .J.: Economicmodels of antiretroviralherapy:searchingor he ptimaltrategy.harmacoeconomics4,631-642 2006)

21.Hellinger,.J.: he ifetime ost f treating person ith IV.JAMA70,474-4781993)

22.Idler, .L., Benyamini,.: Self-ratedealth nd mortality:review f wenty-sevenommunitytudies. .Healthoc.Behav.38,21-37 1997)

23. ILO(Internationalabour rganization):IV/AIDS: threatodecent ork, roductivitynddevelopment2000).Documentordiscussiont the pecial igh levelmeetingn HIV/ IDSandtheworld f work. eneva, June 000.SafeWork ProgrammeonHIV/ IDS.httpV/www.ilo.org/public/english/protection/trav/aids/publ/threathdecentworkeng.pdf24.Kahn,J.G.,Marseille,.: Fighting lobalAIDS: thevalue ofcost-effectivenessnalysis. IDS14,2609-26102000)

25.Kaplan,G., Barell, .,Lusky, .:Subjectivetate f healthndsurvivalnelderlydults. Gerontol.3,S114-S1201988)

26.Keiser, ., Nassar, ., Kvanli,M.B.,et al.:Long-termmpactfhighlyctive ntiretroviralherapyn HIV-relatedealth are.JAcquir.mmune efic. yndr. 7, 14-192001)

27.King, .T. r., ustice, .C.,Roberts, .S., t l.: Long-termIV/AIDS survival stimationn the highly ctive antiretroviraltherapyra.Med.Decis.Making3,9-20(2003)

^ Springer



9/9

412 J.Oliva-Morenot al.

28.Konstam, ., Salem, ., Pouleur, ., et al.: Studies f eft en-tricular ysfunctionnvestigators.aseline uality f ife s apredictorf mortalityndhospitalizationn5,025patients ithcongestiveeart ailure: OLVDinvestigations.m.J. Cardiol.78,890-8951996)

29.Krentz, .B., Auld,M.C.,Gill,M.J., t al.: Thechangingirectcosts f medical are for atients ithHIV/AIDS,995-2001.CMAJ169,06-110(2003)

30.Krentz, .B., Auld,M.C., Gill,M.J.:Thehigh ostof medicalcarefor atients hopsentate CD4

determinants of health care costs of hiv-positive patients in the canary islands, spain

Documents