Backgroundinformation
Hypertension is a significant global public health crisis, affecting approximately one-third of adults worldwide, according to the World Health Organization (2013) In Vietnam, the prevalence of hypertension has notably increased since 1960, rising from about 1% in Northern Provinces to 11.7% in 1992, and further to 16.3% in 2002 A 2012 community-based study reported a prevalence of 25.1%, with only 48.4% of hypertensive patients aware of their condition and a mere 36.3% achieving blood pressure control The incidence of hypertension is higher in urban areas (32.7%) compared to rural areas (17.3%), and awareness, treatment, and control rates remain alarmingly low A preliminary national survey in 2015 indicated that nearly 48% of adults are hypertensive, with increasing rates among younger populations, highlighting a growing public health concern, as emphasized by Professor Huynh Van Minh at a hypertension workshop in Hanoi in May 2016.
Pooradherencehasbeenidentifiedasthemaincauseoffailuretocontrolhyper tension.Astudyonblackpatientsfoundthattotalof75.3%ofcompliantp a t i e n t s h a d a d e q u a t e b l o o d p r e s s u r e c o n t r o l v e r s u s 1 0 2 % o f n o n - c o m p l i a n t p a t i e n t [Eugeniaetal,2005].In another study,patientswho didnotadheretob e t a - b l o c k e r t h e r a p y w e r e 4 5 t i m e s m o r e l i k e l y t o h a v e c o m p l i c a t i o n s fromcor on ary heartd i s e a s e t h a n t h o s e w h o d i d T h e b e s t a v a i l a b l e e s t i m a t e i s t h a t p o o r adherencetotherapycontributestolackofgoodbloodpre ssurecontrolinmoret h a n t w o - t h i r d s o f p e o p l e l i v i n g w i t h hypertension[ H e a l t h l i n e , 2 0 1 5 ]
U n c o n t r o l l e d bloodpressureisputtingpatientatincreasedriskofhypertensi on- associatedtargetorgandamageandcardiovasculardisease[A.C.Cameronet al,2 0 1 6] Highbloodpressureincreasestheriskofischemicheartdisease3- to4-f o l d andofoverallcardiovascularriskby2-to3- fold.Theincidenceofstrokeincreasesapproximately3 - f o l d i n p a t i e n t s with borderlineh y p e r t e n s i o n a n d a p p r o x i m at e ly 8- foldinthosewithdefinitehypertension.Ithasbeenestimatedt h a t 4 0 % o f c a s e s o f a c u t e myocardiali n f a r c t i o n o r s t r o k e a r e a t t r i b u t a b l e t o h y p e r t e n s i o n [Healthline,2015].
Ther a t e o f c o m p l i a n c e w i t h h y p e r t e n s i v e t r e a t m e n t i n o n e - y e a r studyconducted inruralcommunesofmountainousareasintheNorthofV ietnamon388h y p e r t e n s i v e p a t i e n t s a g e f r o m 3 5 t o 6 4 yearso l d s h o w e d thatr a t e o f compliancew a s 5 1 % [ N g u y e n T h i PhuongL a n ,
2 0 1 4 ] A n o t h e r s t u d y w a s c o n d u c t e d on121patientsinpublichospita l,NorthernEthiopiain2013showedthat26.4%isnon- adherent,20.7%ismoderatelyadherentand52.9%isadherent[ A l i etal,2014].
Thea d h e r e n c e o f hypertensivep a t i e n t s h a s b e e n a t t r a c t i n g m a n y r e s e a r c h e r s a n d manyf a c t o r s h a v e b e e n foundtoa f f e c t a d h e r e n c e F a c t o r s r el a t in g tosocio- demographywereidentifiedincludingage(22.3%versus3.8%o f thoseover60yea rsold);placeofliving(16.9%forlivingincityversus10% oft h o s e l i v i n g i n a v i l l a g e ) a n d a b e t t e r l e v e l o f e d u c a t i o n ( 1 7 6 % u n i v e r s i t y graduates versus9%inthosewithlowereducation).Factorsrelatingt onumbero fantihypertensivetabletperday
[ E u g e n i a e t a l , 2 0 0 5 ] o r n o n - c o m p l i a n c e r a t e w a s 3 4 2 % i n which 23.8%ofnon- compliantpatientsrelatedtofinancialreason,16.2%r epo rt ed assideeffects and60%factorscategorizedasmiscellaneousincludedbehavioralfactors( forgetfulness,travelingwithmedication).Perceptionrelatedf a ct o r s (feelin gwell),treatmentdecision(eg.Prescriptionoflocallyunavailabledrugs,multime dicationsanddosingregimen,prematurediscontinuationoftreatmentbyphysician
A study conducted on 225 Nigerian patients highlighted the lack of hypertension education among physicians and the insufficient knowledge of hypertension among patients (Amira et al., 2007) Various factors influence patients' adherence to hypertensive treatment, and these factors can differ across studies and countries Therefore, identifying the factors that affect adherence in hypertensive patients is crucial for implementing effective intervention strategies This research aims to determine the factors impacting compliance with antihypertensive treatment among essential hypertensive patients in hospitals in Ho Chi Minh City, Vietnam.
Researchobjectives
Theg e n e r a l o b j e c t i v e o f t h i s s t u d y i s t o a s s e s s f a c t o r s a s s o c i a t e w i t h adh eren ce toanti- hypertensivetreatmentamongessentialhypertensivepatients.T h e specificobje ctivesare:
Researchmethodsanddata
Thisresearchusesanadjustedquestionnaire(seeAppendix1)desi gnedb a se d o n f a c t o r s i n f l u e n c e treatmenta d h e r e n c e [WHO,2 0 0 3 ] a n d t h e 8 - i t e m s M o r i s k y M e d i c a l S c a l e ( M M A S -
[Oliveiraetal,2012]fordatacollectionviaaninterviewofpatients w h o h a v e t h e i r v i s i t a t O u t p a t i e n t D e p a r t m e n t o r w h o s t a y s I n p a t i e n t Departmento f f o u r hospitals:T a m Duc H o s p i t a l , H C MH e a r t H o s p i t a l , HM C MedicalUniv ersityHospital,a n d D i s t r i c t 6 H o s p i t a l T o measuremedicationtreatmentad h e r e n ce o f pa t i e n t s, t w o methodsa re usedincludes MMAS-
8isdefinedbythescore≥6cutoff[Saartietal,2016]andadherenceinPillcounti ngisdefinedbytherate>80%cutoff[ O s t e r b e r g e t B l a s c h k e , 2 0 0 5 ] L o g i s t i c r e g r e s s i o n i s a p p l i e d t o e s t i m a t e associationb e t w e e n t h e f a c t o r s a n d a d h e r e n c e o f p a t i e n t s V I F t e s t f o r m u l t i c o l l i n e a r i t y a n d auxilia ryr e g r e s s i o n todealwiththeproblemofm u l t i c o l l i n e a r i t y wereap pl ie d , B r e u sc h – P a ga n / Cook-
Weisbergtestwas use dfort e s t ofh e t e r o s k e d a s t i c i t y o f t w o r e g r e s s i o n models.R o b u s t w a s u s e d t o adjustheteroskedasticity.
Structureofthethesis
Thethesisconsistsoffivechapters.Chapter2isliteraturereviewabo utt hef a c t o r s impactmedicationa d h e r e n c e t r e a t m e n t o n e s s e n t i a l h y p e r t e n s i o n C h a p t e r 3 i s r e s e a r c h m e t h o d o l o g y a n d d a t a C h a p t e r 4 m e n t i o n s r e s u l t s o f analysesa n d t h e l a s t c h a p t e r i s d i s c u s s i o n o n t h e r e s u l t a n d l i m i t a t i o n o f t h e research.
Somet h e o r i e s h a v e b e e n p r e s e n t e d i n t h i s s e c t i o n r e l a t i v e t o e s s e n t i a l h y p e r t e n s i v e disease,adherencetomedicationtreatmentandfacto rsassociatetomedicationadherence.Inaddition,evidenceoffactorsfrompreviousstudi esandf r o m WHOr e p o r t 2 0 0 3 h a v e b e e n a l s o r e v i e w e d F r o m t h e t h e o r e t i c a l frameworkandempiricalevidence,theresearchhypothesesande mpiricals t r a t e g y isdeveloped.
Theoreticalliterature
Hypertension andessentialhypertension
Hypertension(highbloodpressure)isdefined asasystolicbloodpressureeq u a l toorabove140mmHgand/ordiastolicbloodpre ssureequaltoorabove90mmHg,
[ W H O , 2 0 1 3 ] C a u s e o f h y p e r t e n s i o n isc l a s s i f i e d intotwotypes.E s s e n t i a l hypertensionis highbloodpressurethatdoesn’thaveaknownsecon darycause.Itisalsoreferredt o a s p r i m a r y h y p e r t e n s i o n
Geneticfactorsarethoughttoplayaroleinessentialhypertension.Diet,str ess,a n d beingoverweightmayincreaseyourrisksofd e v e l o p i n g e s s e n t i a l h y p e r t e n s i o n [Healthline,2015]
Mosthypertensive peo pl e have no symptoms at all.T h e r eis acom m on miscon cep tion thatpeoplewithhypertensionalwaysexperiencesymp toms,butt h e reality isthatmosthypertensivepeoplehavenosymptomsatall.Sometimesh y p e r t e n s i o n causessymptomssuchasheadache,shortnessofbreath,dizziness,chestpain,pal pitationsoftheheartandnosebleeds.[WHO,2013]
Itisdangeroustoignorehighbloodpressure,becausethisincreasesth ec h a n c e s o f l i f e - t h r e a t e n i n g c o m p l i c a t i o n s T h e h i g h e r t h e b l o o d p r e s s u r e , t h e h ig herthelikelihoodofharmfulconsequencestotheheartandbloodvesselsinm ajororganssuchas thebrainand kidneys,thisis knownascardiovascularrisk,a n d canalsobe highinpeople withmildhypertension incombinationwithotherriskfactorse.g., tobacco use, physicalinactivity, unhealthydiet,obesity,d i a b e t e s , highcholesterol,lowsocioeconomicstat usandfamilyhistoryofh y p e r t e n s i o n Lowsocioeconomicstatusandpoorac cesstohealthservicesandmedicationsalsoincreasethevulnerability ofde velopingmajorcardiovascular e v e n t s duetouncontrolledhypertension.
Principleo f h y p e r t e n s i o n t r e a t m e n t : h y p e r t e n s i o n i s a c h r o n i c d i s e a s e , p at i en t s s h o u l d b e r e g u l a r l y f o l l o w e d u p , s h o u l d bep r o p e r l y a n d l o n g - t e r m treatmenttoachieve thehighesteffect.Thegoalofthetreatmentistoac hieve“ t a r g e t bloodpressure”- lessthan140/90mmHgwhichcanminimizetheriskofc a r d i o v a s c u l a r compl ications.Itshouldbetreatedaggressivelyforpatientswithtargetorgandamage,buts houldnotberapidlyloweredbloodpressuretopreventa c u t e anemiaexceptinemergentsi tuation[MOH,2010].
Lifestylec h a n g e t o l o w e r b l o o d p r e s s u r e i s r e c o m m e n d e d f o r a l l h y p e rt en s iv e patients[MOH,2010].Lifestylechangesinclude:exercise atleast3 0 minutesaday,eatalow-sodium,low-fatdietthat’srichinpotassiumandfiber
(don’tincreaseyourpotassium intakewithout yourdoctor’s permission if youh a v e kidneyproblems),loseweightif youareoverweight, quitsmoki ng,limita l c o h o l intaketonomorethanonedrinkadayifyou’reawomanandtwodrink sa dayifyou’reaman,reduceyourstresslevels[Healthline,2015]
Iflifestylechangesarenot sufficientforcontrollingbloodpressurean dp r e s c r i p t i o n medicationisneeded[Healthline,2015].Bloodpressuredrugswor ki n severalways,suchasremovingexcesssaltandfluidfromthebody,slowingt h e h e a r t b e a t o r r e l a x i n g a n d w i d e n i n g t h e b l o o d v e s s e l s [ W H O , 2 0 1
3 ] Themostc o m m o n b l o o d p r e s s u r e m e d i c a t i o n s i n c l u d e b e t a b l o c k e r s , c a l c i u m channelb l o c k e r s , d i u r e t i c s , a n g i o t e n s i n - c o n v e r t i n g e n z y m e ( A C E ) , i n h i b i t o r s , angiotensinIIreceptorblockersan dRenininhibitors.[Healthline,2015]
Adherence
Adherencei sd e f i n e d a s “thee x t e n t t o w h i c h a p e r s o n ’ s b e h a v i o r – takingm e d i c a t i o n , f o l l o w i n g a d i e t , a n d / o r e x e c u t i n g l i f e s t y l e c h a n g e s , correspondswithagreedrecom mendationsfromahealthcareprovider”.T h i s d ef i n it io n i s a mergedv e r s i o n o f t h e d e f i n i t i o n s o f Haynesa n d R a n d [ W H O , 2 0 0 3 ]
Medicationadherenceisgenerallydefinedastheextenttowhichp at i en ts t a k e d r u g s a s p r e s c r i b e d b y t h e i r h e a l t h c a r e providers.
Several factors significantly impact adherence to hypertension treatment, with the asymptomatic nature of the disease and its lifelong duration being primary contributors to poor adherence Additional determinants include demographic factors, patients' understanding and perception of hypertension, the healthcare provider's treatment delivery approach, the patient-provider relationship, influences from health systems, and the complexity of antihypertensive drug regimens.
Poors o c i o e c o n o m i c s t a t u s , i l l i t e r a c y a n d u n e m p l o y m e n t a r e i m p o r t a n t r i s k f a c t o r s f o r p o o r a d h e r e n c e O t h e r i m p o r t a n t p a t i e n t - r e l a t e d f a c t o r s m a y includeunderstandingandacceptanceoft h e disease,per ceptionofthehealthr i s k r e l a t e d t o t h e d i s e a s e , a w a r e n e s s o f t h e c o s t s a n d b e n e f i t s oftreatment,a c t i v e par ti ci pa ti on i n mo ni to ri ng a n d d e c i s i o n - m a k i n g i nr e l a t i o n t omanagement ofthedisease.[WHO,2003]
Theinfluenceoffactorsrelatedtothehealthcareprovideronadherence tot h e r a p y f o r hypertensionh a s n o t b e e n s y s t e m a t i c a l l y s t u d i e d S o m e o f t h e morei m p o r t a n t f a c t o r s p r o b a b l y i n c l u d e l a c k o f k n o w l e d g e , i n a d e q u a t e time,l a c k o f i n c e n t i v e s a n d f e e d b a c k o n p e r f o r m a n c e T h e r e s p o n s i b i l i t y f o r ad he r e n c e mustbesharedbetweenthehealt hcareprovider,thepatientandthehealth care system Goodrelationships between thepatients and theirhealth careprovidersa r e t h e r e f o r e imperativef o r g o o d a d h e r e n c e H e a l t h s y s t e m s - r e l a t e d issuesalsoplayanimportantroleinthepromotionofadherence.
Improving access to essential medications, particularly through sustainable financing, affordable pricing, and reliable supply systems, significantly impacts patient adherence, especially among lower-income populations Key factors influencing adherence to antihypertensive therapy include drug tolerability, regimen complexity, treatment costs, and duration Regimen complexity, characterized by dosing frequency, the number of concurrent medications, and changes in antihypertensive prescriptions, has been linked to poor adherence Studies show that fewer daily doses, the use of mono-therapy, and less frequent changes in medication contribute to improved adherence rates.
Experimentalresearchreviews
Adherentmeasurement
Therea r e m a n y t y p e o f q u e s t i o n n a i r e s wereu s e d f o r a s k i n g p a t i e n t ’ s adher ence rating.Patients’self- reportsisusedtomeasureadherence,patientsisa s k e d thetotalnumberoftablets prescribedperweekandhowmanypillstheytookandmissedinthelast3,5and 7days,respectively.Adherencerateswerecalculatedas‘pillstakenoveraspe cificperiodoftime,dividedbypillsp re sc ri b ed forthatspecificperiodoftime’[Has hmietal,2007].
4)isusedtomeasurethecomplianceoftreatmentinchronicconditionssuchashype rtension,itmeasuresb o t h i n t e n t i o n a l a n d un- intentionaladherencebasedonforgetfulness,c a r e l e s s n e s s , stoppingmedication whenfeelingbetter,andstoppingmedicationw h e n feelingworse.MMASincludi ng4- itemquestionnaire,thescaleisscored1p o i n t foreachanswerof‘NO’and0pointsfor eachanswerof‘YES’.Thetotalscorerangesfrom0(non-adherent)to4
The Morisky Medication Adherence Scale (MMAS-8) is a self-report questionnaire designed to assess medication adherence through eight specific questions To minimize bias, the questions are structured to discourage respondents from simply answering "yes." Items 1 through 7 offer binary response options of "yes" or "no," while item 8 utilizes a 5-point Likert scale Each "no" response is scored as "1," allowing for a comprehensive evaluation of adherence levels.
In the MMAS-8 adherence assessment, responses are scored with "yes" rated as 0, except for item 5 where it receives a score of 1, and "no" rated as 0 For item 8, selecting response "0" results in a score of 1, while response "4" scores 0 Responses "1," "2," and "3" are rated as 0.25, 0.75, and 0.75, respectively Total scores range from 0 to 8 and are classified into three adherence levels: high adherence (score of 8), medium adherence (scores of 6 to
