Potentially Inappropriate Medication at a Private Hospital

Abstract

The use of certain medications in geriatrics when potential risks outweigh the potential benefit and an effective alternative is available is called as Potentially Inappropriate medication. Because geriatrics are more sensitive towards adverse effects of medications. Beers criteria which is updated and reviewed by American Geriatric society list out 53 medications/therapeutic classes of drugs to be avoided in geriatrics. Methodology: A prospective observational study was conducted for 9 months in a 650 bed private corporate hospital, South India. All geriatric patients admitted in the hospital during the study period was included. Beers Criteria 2013 were used to identify potentially inappropriate medications. Result: The prevalence of PIM use (52%) was significantly higher in study population. An avg of 10 drugs were taken by the study population. A total of 215 medications were identified as PIMs. Among them 195(90%) medications should be avoided by the geriatrics independent of their condition (category I). 66(60%) of the study population had used more than one PIMs. 91(83%) of the PIM users had atleast one DRPs and the mean DRPs value of the PIM users were 1.591.3. Conclusion: High prevalence of PIMs in the study population signifies the need of monitoring geriatric prescriptions.

Key words: PIMs, Beers Criteria, Geriatrics

Introduction

In recent years proportion of geriatric hospital admission with comorbidity and polypharmacy has been increasing continuously ^{(1, 2)}. Adverse drug events (ADRs) are the most common reason for hospital admission, but sometimes it’s not identified. Medication errors (MEs) or conventional adverse drug reactions (ADRs) are the common reason for adverse drug events which ends in clinical symptoms. Overall, elderly patients need greater attention to drug therapy and safety parameters ^{(1, 3-5)}.

Greater attention is needed for geriatric population due to age related pharmacodynamics and pharmacokinetic changes. But appropriate pharmaceutical care for elderly are determined on the basis of clinical trial conducted with adult population.⁽⁶⁾ The burden of harm resulting due to the use of multiple drugs in geriatric populations is a major health related problem in developed countries. A research study reveals that around one in four geriatrics admitted to hospitals are prescribed with at least one inappropriate medication and potentially preventable adverse drug reactions accounts for nearly 20% of all inpatient deaths ⁽⁷⁾.

The assessment of potentially inappropriate medication (PIM) in geriatric is a challenging work and there is a need for considering many factors which influences the prescribing as well as outcome. Eight well known tools are available to identify the PIMs and studies reports that Beers criteria is the best and easy one to assess the PIMs. Beers criteria also has the advantage over others because it is periodically updated ⁽⁸⁾.This study therefore aimed to investigate the prevalence of PIM use on geriatric population using Beers criteria 2012 and its association with Drug Related Problems (DRPs) .

Methodology

Study Site: The work entitled “A study on prevalence and impact of Potentially Inappropriate Medication use in geriatrics at a private corporate hospital” was carried out in a 640 bedded private corporate hospital, South India.

Study Design: Prospective –Observational study.

Study Period: Nine months.

Inclusion criteria: Patients above age of 65 yrs.

Exclusion criteria: The patients who are unwilling to participate in the study and out patients

METHOD: A regular ward rounds was carried out in all the wards of General medicine. Each patient’s medication profile was reviewed. Patients who met the inclusion criteria were briefed on the project with the help of patient information form and if they are willing to participate in the study their consent was obtained. The data from medical chart were recorded in customized data entry form.

The prescribed drugs were evaluated and PIMs use were identified with the help of Beer’s criteria. The drugs which are identified as PIM are categorized into following:

1. Potentially inappropriate medications /classes to avoid in geriatrics,
2. Potentially inappropriate medications /classes to avoid in geriatrics with certain pathological condition that the listed PIM use can exacerbate
3. Medications to be used with caution in geriatrics.

ADRs associated with PIMs use were assessed. Drug interaction and ADR was monitored and reported. DRPs and Drug Risk Ratio (DRR) were calculated for PIMs. DRPs were the sum of ADR, drug interaction and drug allergy.DRR was calculated as the number of DRPs in relation to how often the drug was used (DRPS/number of times used).

Results and Discussion

In the study period, 212 patients were included in the study as per inclusion criteria and exclusion criteria. 110 (52%) patients were found to be prescribed with PIMs listed in Beers criteria (fig no: 01). A similar study conducted by Birader K et al (2013) ⁽⁹⁾ reported that PIM prevalence were 38% in their study population. Increased anxiolytics use as a prophylaxis for hospital related anxiety might be the reason for high prevalence of PIM than the later study. The total number of patients in study population were 110. Among them 62(56%) were males and 48(44%) were females.The study result reveals that PIMs user are mostly males. A similar study conducted by Birader K et al (2012) ⁽⁹⁾ reported that prevalence of PIM use is more among males than females.

The age categorization of PIM users was done. The maximum age of PIM users was 93 years and mean age of PIM users was found to be 70.2±5.77. The median age for PIM users was 68.5 years.

The result indicated that age group of (65-69) were commonly prescribed by PIMs. This results compared with a previous study carried out by Birader K et al (2012) ⁽⁹⁾ which also reports that PIMs were frequently prescribed in the age group of 65-69 years. The social habit of the PIM users shows that 8(7%) patients were smokers and alcoholics, 14(13%) patients were alcoholics, 21(19%) patients were smokers and 67(61%) patients were teetotalers in PIM users.

The comorbidities of the PIM users was analyzed. There were 52 (47%) suffering from hypertension and 32(29%) were suffering from DM. The results shows that most of the study group had comorbidities of hypertension followed by DM and CVDs. A similar study conducted by Fouquet A ⁽¹¹⁾ also reported that most common diagnosis among their study population was hypertension and diabetes.

The number of drugs prescribed for the PIM users were calculated (fig no: 2). The mean number of drugs per prescription was 9.9±2 with the maximum of 16 drugs and minimum of 5 drugs prescribed. The above results signifies that all prescriptions were in polypharmacy category. A similar study conducted by Blozik E ⁽¹²⁾ concluded that one of the main factor for PIM use is “polypharmacy”.

The number of PIM drugs per prescription in the study population was calculated (Fig no: 3). The result reveals that 44(40%) were using one PIM drug, 50(45%) were using two PIMs, 14(13) were using three PIMs, 1(1%) were using 4 PIMs and the maximum of 5 PIMs use were found in 1(1%) of the study population. 66(60%) of the study population consumed more than one PIM. The mean was found to be 1.8±0.78 and an avg of 2 PIM was used by the study population. A similar study conducted by Dormann H (2013) ⁽¹³⁾ were reported that 87% of the study population consumed at least one PIM.

Among the PIM users the total number of PIM drugs was calculated and it was found to be 215 drugs. PIM users were categorized into three groups according to Beers criteria. (Table no: 2) There were 195(90%) belongs to category I, 12(6%) were in category II and 8(4%) were in category III.

The individual categories of PIM was analyzed. It was found that alprazolam 57(52%), clonazepam 17(15%), hyocyamine 10(9%), Lorazepam 10(9%), hydroxyzine 10(9%), zolpidem 10(9%), ketorolac 10(8%) were prescribed in category I (table no: 3). A similar study conducted by Birader K et al (2013) ⁽¹⁶⁾ reported that alprazolam and cimetidine were frequently used PIM among their study population.

Use of hyocyamine in constipation 3(25%) accounts for the most frequent inappropriate drug use in category II (table no: 4). Hydroxyzine in constipation 2(17%), cyproheptidine in constipation 2(17%), ketorolac in PUD 2(17%), clonazepam in frequent fall 1(8%), ketorolac in CHF 1(8%) and theophylline in insomnia 1(8%) were other category II inappropriate medication use.

Use of escitalapram 3(40%), mirtazapine 2(30%), fluoxetine 1(10%), sertraline 1(10%) and Duloxetine 1(10%) were the category III PIMs (table no:5).

The DRP among the PIM users were analyzed (fig no: . It was found that 19(17%) of the PIM users were free from DRPs. Majority of the study population had at least one drug related problems. The mean value of DRP in the study population was found to be 1.59±1.3. The minimum observed number of DRP per patient was one and maximum observed number of DRP per patient was six.

The ADR use was monitored in the study population. A total number of 40 ADR associated with PIM use (Fig no:5) and 14 ADR associated with nonPIM use were identified. The study result reveals that one among three PIM users were found to have at least one ADR. A similar study conducted by N. Nixdorff et al (2008) were also reported that PIM users were found to experience ADR most frequently than nonPIM users.

As a part of our study, screening of drug interactions were done. A total number of 131 major drug interactions were identified, in that 111 were unique. Among the drug interactions found 16(12%) were PIM-PIM drug interactions, 39(30%) were PIM-other drugs drug interactions and 76(58%) were caused by non PIM drugs (table no: 6).

Drug risk ratio were calculated for the study population (table no:7). It was observed that prochlorperazine had the highest DRR (4) followed by phenobarbitone (2), digoxine (2), pentazocine (2) and duloxetine (2).

The statistical analysis of obtained results has been done using statistical tools. The association of different variables are analyzed using 2 test.

On assessment of association between “number of comorbidities” with “number of drugs” and “number of PIMs” (table no:8), the result proved that “number of comorbidies” are statistically associated with “the number of drugs” at 0.001 level of significance and “number of PIMs” at 0.05 level of significance. It means that as number of comorbidity increases polypharmac and PIM use also increases.

On assessment of association between “number of drugs” and “number of PIMs” (table no: 9), the result proved that “number of drugs” are statistically associated with “number of PIMs” at 0.05 level of significance. This result proves that polypharmacy is one of the reason for PIMs.

On assessment of association between “number of DRPs” with “number of drugs” and “number of PIMs” (table no:10), the result proved that “DRPs” are statistically associated with “number of PIMs” at 0.01 level of significance but not associated with “number of drugs” at 0.05 level of significance.

This result proves that DRPs is more associated with PIMs than polypharmacy which means it not the number of drugs contributing to DRPs but the use of PIMs.

Conclusion

Our study identified a high prevalence of PIMs use and associated DRPs in the study population. DRPs due to PIMs is preventable. Development and implementation of new criteria or modification of already existing criteria such as Beers criteria, START STOPP criteria which will helps in safe prescribing practice can reduce the PIMs use.

References

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Tables and figures

Table no:1 Number of PIM per Prescription

Table no:2 Categories of PIM

Table no: 3 Category 1(PIM drugs/classes to be avoid in geriatrics)

Table no: 4 Category II (PIM to be avoided in certain pathological condition)

Table no: 5 Cateegory III (PIMs to be used with caution)

Table no:6 Categories of Drug Interactions

Table no.7 Drug Risk Ratio

Table no:8 Association of no. of comorbidities with no. of drugs and PIMs

.

Table no: 9 Association of no. drugs and no. PIMs

Table no:10 Association of DRPs with no. of drugs and PIMs

Fig no:1 Prevalence of PIMs

Fig no:2 Number of Drugs Prescribed per Patient

Fig no:3 Number of PIM per Prescription

Fig no: 4 Adverse Drug Events and Its frequency

Fig no:5 Adverse Drug Events and Its Frequency