Backgroundinformation
Hypertension is a significant global public health crisis, affecting approximately one-third of adults worldwide, as noted by the WHO in 2013 In Vietnam, the prevalence of hypertension has dramatically increased since 1960, when it was estimated at just 1% in Northern Provinces, rising to 1.9% by 1976 A national survey in 1992 revealed a prevalence of 11.7% among adults, which surged to 16.3% in 2002 and reached 18.8% in adults aged 25-64 in rural areas by 2005 A community-based study in 2012 reported a prevalence of 25.1%, with only 48.4% of hypertensive patients aware of their condition and just 36.3% achieving blood pressure control The incidence of hypertension increased with age and was notably higher in urban areas (32.7%) compared to rural areas (17.3%) Alarmingly, a preliminary national survey in 2015 indicated that nearly 48% of adults were hypertensive, with rising rates among younger individuals, highlighting a critical 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 revealed a lack of hypertension education among physicians and limited knowledge of hypertension among patients (Amira et al., 2007) Numerous factors influence patients' adherence and non-adherence to hypertensive treatment, which can vary across different studies and countries Therefore, identifying these factors is crucial for implementing effective intervention strategies This research aims to pinpoint the factors affecting 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.
Numerous factors have been identified as contributors to medication adherence, with extensive reviews highlighting their significance Among these, the asymptomatic nature of hypertension and its chronic duration are critical reasons for poor adherence Additional determinants include demographic factors, patients' understanding and perception of hypertension, the healthcare provider's communication style, the relationships between patients and healthcare professionals, 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 medications through sustainable financing, affordable prices, 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, drug costs, and treatment duration The complexity of a treatment regimen, characterized by dosing frequency, the number of concurrent medications, and changes in antihypertensive prescriptions, has been linked to poor adherence Studies indicate that fewer daily doses, the use of mono-therapy, and reduced 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 The wording of these items is strategically crafted to minimize "yes" responses, ensuring a more accurate reflection of adherence behavior Items 1 to 7 offer binary response options of "yes" or "no," while item 8 utilizes a 5-point Likert scale for responses Each "no" answer is assigned a score of "1," contributing to the overall assessment of a patient's adherence to their medication regimen.
In a study evaluating medication adherence using the MMAS-8 scale, responses were scored on a scale from 0 to 8 Each "yes" response was rated as 0, except for item 5, where it was rated as 1, while "no" responses were rated as 0 For item 8, a response of "0" scored 1 point, and a response of "4" scored 0 points, with responses "1," "2," and "3" scored as 0.25, 0.75, and 0.75, respectively The total scores categorize adherence levels into high (score = 8), medium (score between 6 and
