タイ東部の地域病院における高齢者の医薬品適正使用のための実態調査

Potentially Inappropriate Medications of Elderly in Community Hospital in Eastern ofThailand
2018 Dissertation Doctor’s Degree

Applicant Vanida Prasert (ヴァニ－ダ，プラサート）
Advisor Manabu Akazawa

Background and rationale
Thailand is an upper-middle income country in South East Asia, whose population is quicklyaging. Almost older Thai citizens have been continuously prescribed multiple medicines thatassociated with the high risk of adverse drug reaction (ADRs). These problems are related topotentially inappropriate medication (PIM) use in the elderly. PIM has been defined as amedication that puts patients at risk rather than having benefits and includes prescription
medications with drug–drug and drug–disease interactions. Currently there are several
screening tools to identify PIM. The original tool was the Beers Criteria, which was publishedin 1991 in the United States and updated in 2015. Medicines should be avoided in the elderly
owing to drug-disease interactions, drug-drug interactions, the need for caution in elderly, andeffects on kidney function. The screening tool of older people’s prescriptions (STOPP) wasexplicit criteria published in 2008 in Europe and updated in 2014. The medication lists wereorganized by physiological organ systems and should be avoided drug-drug interactions, drugdisease interactions, drugs that increase the risk of falls, and duplicate drug class prescriptions.
Irrational prescribing is a problem in the Thai health care system, especially PIM prescribing
to elderly patients. A large-scale prevalence of PIM was found 30–60% in community hospitals
by identifying Beer and STOPP criteria. Over half of PIM and ADR problems are associatedwith the prescribing process by physicians. In 2011, the Ministry of Public Health (MOPH)
launched the Rational Drug Use (RDU) policy for improving drug safety in patients especially
PIM use. The Lists of Risk Drugs for Thai Elderly (LRDTE) as the Thai explicit for identifying

PIM was developed from the Beers and STOPP Criteria by Christine M et al. (J Am GeriatrSoc 2012) and Gallagher P et al. (Int J Clin Pharmacol Ther 2008). The medication lists
considered the age group in elderly aged over 60 years and the severity of medication risk. In
addition, a novel computerized decision support systems (CDSS) as the automated alert system
integrated PIM lists base on LRDTE criteria into the electronic prescribing of the hospital
software to make appropriate prescription changes by physician. LRDTE criteria and CDSS
for PIM associated with the RDU policy and were supported by MOPH to improve patient’s
safety. The prevalence of PIM using the LRDTE has not been determined and the effectivenessof this CDSS for PIMs has not been clearly established in Thailand. Therefore, this study aimed
to examine the prevalence of PIM use based on the LRDTE, to address the PIM problem byidentifying factors that influenced PIM use, and to evaluate the effect of a CDSS on PIM
prescriptions for elderly patients in Thai community hospitals.
METHODS
Phase IA retrospective cross-sectional descriptive study was conducted using the computerized
database at four community hospitals in Thailand between April 1, 2014 and March 31, 2015.
PIMs were defined using the LRDTE that is categorized by age and severity of medicine. Age
was separated into two categories: 60-74 years and 75 years and over. Medicine wascategorized into three severity levels: mild is used within the short term or with intensive
monitoring, moderate is avoid by using alternative choices, and severe is not recommended
and no benefit.
The population studied included elderly patients aged 60 years and older who had at least 2
pharmacy claims and visited as an outpatient over a 1-year period during fiscal year 2014. Four
hospitals participated in the study. Descriptive statistics and multivariate logistic regression
were used to identify common factors (patient and health service utilization) and Thai regionspecific predictors of PIM use including 1) health insurance schemes, 2) hospitals, and3) physicians. There are three health insurance schemes; the civil servants medical benefit
scheme (CSMBS) for government employees, the social security scheme (SSS) for private
employees, and the universal coverage scheme (UCS) for the remaining population including
elderly. CSMBS are still the best in Thailand because CSMBS get free choice of the contractor
providers and can access both essential drug (ED) and non-essential drug. Each hospital had
different characteristics in terms of the number of bed and physician. Hospital A was a firstlevel hospital (F1), which has 60 beds and more, general practitioners (GP), and specializedpractitioners (SP). The other three hospitals (B to D) were second-level hospitals (F2), whichhave 30 beds and more and were without SP.
Phase II
The CDSS for PIM detection in this study, the alert system was incorporated with LRDTE
criteria into electronic prescribing at four hospitals and was developed by Ploylearmsang et al.
(J Health Syst Res 2017). The retrospective cohort study design comprised two phases with aduration of 12 months each: pre-CDSS (October 2015 to March 2016) and post-CDSS (October2016 to March 2017). A descriptive analysis was used to analyse the common PIM used ineach PIM level pre- and post- CDSS. Chi-square tests were used to compare the rate of PIM
prevalence in each PIM level pre- and post-CDSS implementation.
RESULTS AND DISCUSSION
I. Applying the Lists of Risk Drugs for Thai Elderly (LRDTE) as a mechanism to account forpatient age and medicine severity in assessing potentially inappropriate medication use
Prevalence of PIM use identified using the LRDTE
Of a total of 13,274 elderly patients, 79% (10,536/13,274) were prescribed at least one PIM.
Amlodipine (32%), omeprazole (30%), and tramadol (18%) were the most commonlyprescribed PIMs in elderly patients. The high PIM prevalence was found in this study because
the medicine lists in the LRDTE criteria covered current standard treatment guidelines andhospital formularies. Therefore, the new LRDTE criteria should suggest to fulfill the RDU
policy to improve the medicine safety among Thai elderly.
Factors influencing PIM use in elderly patients for drug policy perspective
After adjustment for patient and utilization factors (Model 1), positive associations wereidentified between female gender, all comorbidities except COPD/asthma, 4 or more outpatientvisits, 5 or more diagnoses, and 6 or more medications (Figure 1-a). By adding Thai regionspecific factors (Model 2), most factors remained statistically significant predictors (excluding
female and outpatient visits). Moreover, Hospital D [OR 1.24; 95% CI 1.07-1.43] and generalpractitioner prescribers [OR 2.80; 95%CI 2.44-3.21] were independent predictors for PIM use
as Thai region-specific factors. Health insurance schemes were not independent predictors afteradjustment for common factors (Figure 1-b).
The factors positively associated with PIM use in this study were multi comorbidities,
increased number of diagnoses, frequency of outpatient visits, and polypharmacy. After
including the Thai region- specific factors in the model, the hospital and general practitioner
factors were an important predictor that associated with PIM use. The revision of formularies
and educational programs or the PIM alert system for physicians are needed to improveprescribing.

a) Patient and utilization factors (Model 1)b) Thai region-specific factors (Model 2)

Figure 1 Factors that influenced potentially inappropriate medication use in Thai elderly.

II. Effect of a computerized decision support system on potentially inappropriate medicationprescriptions for elderly patients in Thailand
A total of 11,258 patients were included in the period in pre-CDSS and 11,915 patients wereincluded in post-CDSS. The overall prevalence of PIM prescriptions post-CDSS significantly
decreased from 88% to 74% (Figure 2-a). The tendency of PIM prevalence post-CDSS between
overall and each hospital were similarly reduced. Mild and moderate PIM levels weresignificantly reduced from 72% to 49% (Figure 2-b) and from 65% to 49%, respectively(Figure 2-c). All hospitals had only one severe PIM, which was hyoscine, and its prevalence
was reduced from 5.0% to 2.0% (Figure 2-d), but the change was not significant (p = 0.74).
CDSS of PIM change physician’s prescription behaviour to avoid PIM because PIM prevalenceof overall and each hospital reduced. The CDSS for PIM showed specific medication warnings,
was easy to use, and provided real-time alerts for physicians. Even though, the tendency ofPIM prevalence was similarly reduced in overall and each hospital, PIM prescription was stillhigh. The main cause might be the restriction of hospital formulary. Physician have noalternative medicine to avoid PIM prescription. Therefore, the hospital formulary should berevised for preventing PIM prescription. The prescriptions of mild and moderate PIMs werereduced but still had a high proportion of PIM prescriptions. Those PIM levels may have thebenefits more than risk in elderly patients. Therefore, the continuous monitor for preventing
long-term prescription, should be realized. For the CDSS on severe PIM, PIM level was not
significantly reduced. The prevalence of severe PIM in pre-CDSS was very small because onlylimited elderly patients received it. When considering the relative reduction, a big change wasobserved between pre-and post-CDSS accounting for 60% reduction. Even though, severe PIM
in each hospital should be zero, this PIM was still prescribed. All hospital has only Hyoscine(Antispasmodic medicine) as severe PIM so physicians have no alternative medicine to avoid
PIM prescription. Therefore, formulary should be revised to avoid PIM.

a) Overall PIMb) Mild PIM (medicine use within short term use
or with intensive monitoring)c) Moderate PIM (medicines are notrecommend, avoid by usingd) Severe PIM (medicines are not recommendand no benefit)

alternative choices)

Figure 2 PIM prevalence of overall and each PIM level pre- and post-CDSS
CONCLUSION
The prevalence of PIM was 79% by using LRDTE. The hospital and general practitioners as
the Thai region- specific factors associated with PIM use. Using CDSS for PIM can reduce
PIM prescription can change physician’s prescription behaviour but the effort to revise hospital
formulary is still important to avoid PIM.
REFFERENCES
1. Prasert V., Akazawa M., Shono A., Chanjaruporn F., Ploylearmsang C., Muangyim K.,
Wattanapongsatit T., Sutin U., Res Social Adm Pharm., 14(5):451-458 (2018).
2. Prasert V., Shono A., Chanjaruporn F., Ploylermsang C., Boonnan K., Khampetdee A.,Akazawa M., J Eval Clin Pract., in press.