PATTERN OF MEDICATION USE AMONG ELDERLY INPATIENTS IN A TERTIARY CARE HOSPITAL OF NORTHEAST INDIA

Objectives: The objective of the present study was to assess the pattern of medication use among elderly inpatients of internal Medicine Wards and to evaluate inappropriate prescribing with the help of Beers criteria 2019. Methods: It was a retrospective hospital data-based study. Data were obtained from treatment charts of elderly inpatients stored in the Medical Records Department. Total 236 treatment record charts of patients ≥60 years of either sex was obtained from the period of July 2015 to December 2015 and the information were noted in predesigned pro forma. Results: The mean±SD age of the patients was 69.07±7.72 years with male preponderance (58.5%). Maximum number of patients were having respiratory disorders (57.6%), followed by kidney diseases (20.8%), cardiovascular diseases (18.6%), and so on. A total of 2683 drugs were prescribed with average number of 10.68±4.74 drugs per prescription. Only 363 formulations were prescribed by their generic names and 29.1% drugs were prescribed as fixed dose combinations. Polypharmacy was seen in 91.5% and 39%, respectively, in hospital stay and during discharge. About 60.5% drugs were prescribed from the National list of essential medicine. Total 57 drugs were found to be potentially inappropriate. About 22% patients received at least one drug which was potentially inappropriate according to Beers criteria and around 14% drugs were prescribed inappropriately. Conclusion: This study suggests that use of potentially inappropriate medications is common in elderly patients, some of them associated with high degree of risk in terms of worsening of the co-morbidity or drug-drug interactions. There is a need for nationwide assessment and strategies that may reduce or overcome such high prevalence.


INTRODUCTION
The number of elderly people is increasing worldwide. There were 962 million people 60 years or over globally in 2017, which were more than twice as large as in 1980, when there were 382 million older people worldwide. The number of older people is expected to reach nearly 2.1 billion in 2050. In 2017, people 60 years or over in India were 9.4% of the total population, which accounted to 125.69 million [1]. This profound shift in the population of elderly people brings with it a variety of social, economic, and health-care policy challenges [2]. Moreover, a large number of elderly people suffer from chronic and degenerative pathology, leading in turn to a demand for more medication.
Medications play crucial role in geriatric healthcare as they treat chronic diseases, alleviate pain, and improve quality of life. About 55% of community prescriptions dispensed in 2001 in UK were meant for people ≥60 years of age [3]. Interindividual differences in age-related pharmacokinetic and pharmacodynamic changes as well as presence of comorbid conditions have to be considered while prescribing medicines in elderly population. Polypharmacy, for number of comorbid conditions, leads to higher incidence of side-effects and harmful drugdrug interactions and drug-disease interactions, with often atypical presentation. Polypharmacy is the concomitant administration and use of five or more medications and it is usually common among older adults [4,5]. Likewise, underuse of medication seems to have a negative effect on health outcomes for older people, which include functional disability, health services use, and death [6]. About 20-25% of hospital admissions in elderly population are attributed to adverse drug reactions and about half of these reactions are preventable. Moreover, there is limited evidence available to guide prescribing for elderly; the prescribers tend to depend on data available for younger subjects. Furthermore, these patients are often excluded from drug trials making it difficult for the clinician to weigh up the benefits versus risks [4,7].
To achieve the maximum therapeutic outcome with minimum adverse reactions, it is important to identify the pattern of inappropriate use of medicines in this population. Today, several tools are used to evaluate the prescription of potentially inappropriate medication (PIM) in older people. PIM is a drug, use of which outweighs the risk of an adverse event than its clinical benefit, particularly when there is a safer or more effective alternate therapy for the same condition [6]. Explicit criteria to identify certain drugs as PIMs are developed for elderly patients. The most common among them are the American Geriatrics Society (AGS) Beers criteria, Screening Tool of Older Person's Prescriptions/Screening Tool to Alert doctors to the Right Treatment tools, Improved prescribing in the elderly tool, and PRISCUS (Latin for "old and venerable") list [8,9]. The Beers criteria were initially developed by an expert consensus panel in 1991, which are comprehensive set of explicit criteria for potentially inappropriate drug use in elderly aged 65 years and above. Medications are grouped into five categories: (i) Those potentially inappropriate in most older adults, (ii) those that should typically be avoided in older adults with certain conditions, (iii) drugs to use with caution, (iv) drug-drug interactions, and (v) drug dose adjustment based on kidney function. The criteria have been repeatedly updated, most recently in 2019, and are available on the AGS website [10].
The literature related to the prescription pattern analysis in geriatric population and the use of PIMs from India is meager. Hence, this study was undertaken at a tertiary care teaching hospital of Northeast India with the objectives of assessing the pattern of medication use among elderly inpatients of internal Medicine Wards and to evaluate the level of inappropriate prescribing with the help of Beers criteria 2019.

METHODS
It was a retrospective hospital data-based study carried out after obtaining due approval from the Institutional Ethics Committee. Data were obtained from treatment charts of elderly inpatients stored in the Medical Records Department (MRD). Total 236 treatment record charts of patients ≥60 years of either sex were obtained from the period of July 2015 to December 2015 and the information were noted in pre designed pro forma which included patient's demographic details, CR number, diagnosis, duration of hospitalization, and prescription characteristics such as name of the drug, strength and dosage form, whether prescribed in generic name or not. All drugs were coded as per the WHO Anatomical Therapeutic and Chemical Classification coding system. Prescriptions were also analyzed using the WHO prescribing indicators: NLEMs 2015 of India were used for assessing the number of drugs prescribed from the essential list [11]. The drugs which were prescribed by their brand names were identified by their generic names and were evaluated. In this study we included elderly patients 60 years and above, but for evaluation of the PIMs with the help of Beers criteria 2019, we evaluated only those treatment charts of patients >65 years, which accounted for 164 prescriptions.

Statistical analysis
Collected data were entered and analyzed in Microsoft Office Excel 2007. Data were expressed as mean±SD, numbers, and percentages.

RESULTS
A total of 236 treatment charts were reviewed during the study period. The mean±SD age of the patients was 69.07±7.72 years (range: 60-92 years). About 55.9% patients were in the age group of 60-69 years, followed by 31.4% and 11.4% in the age groups 70-79 years and 80-89 years, respectively. Lowest number of patients (1.3%) was in the age group >90 years. There was total 138 (58.5%) males and 98 (41.5%) females. Maximum number of patients was having respiratory disorders (57.6%), followed by kidney diseases (20.8%), cardiovascular diseases (18.6%), diabetes mellitus (16%), and so on (Fig. 1). The average duration of hospital stay was 6.4 days (range 1-27 days).
A total of 2683 drug formulations were prescribed. The mean±SD of the number of drugs prescribed per prescription was 10.68±4.74. (range: 2-30). Drugs acting on gastrointestinal (GIT) system followed by antimicrobial agents, respiratory system drugs and cardiovascular drugs were the most common class of drugs prescribed to the patients (Table 1). The percentage of prescriptions with ≥5 drugs during hospital stay and during discharge was 91.5% and 39%, respectively. Total 781 (20%) FDC were prescribed. 1624 (60.5%) drugs were prescribed from the NLEM. 2320 (86.5%) drugs were prescribed by their brand names. The drug prescriptions were analyzed for the WHO prescribing indicators ( Table 2).
Out of 57 drugs which were found to be PIM according to Beers Criteria 2019, 52.6% (n=30) medications were potentially inappropriate in most elder adults, 43.9% (n=25) medications were typically to be avoided in older adults with certain conditions such as heart failure and syncope, 28.1% (n=16) drugs were to be used with caution in older adults, 28.1% (n=16) drugs were to be avoided due to their potential for clinically significant drug-drug interactions, and 15.8% (n=9) drugs were to be avoided or use with reduced dose in older adults with renal impairment.

DISCUSSION
Drug therapy is most common and important treatment in elderly people. Most geriatric patients take medications for chronic conditions such as diabetes, hypertension, and heart failure which accounted for long durations of therapy apart from drugs used for shorter periods for symptomatic relief. Moreover, geriatric patients have many comorbidities which lead to prescription of many drugs making them susceptible to drug-disease and drug-drug interactions.
The age group of 60-69 years had the highest number of patients (55.9%); whereas only 1.3% patients were above 90 years. The average number of drugs per patient was 10.68±4.74 which was higher than 7.37±2.22 and 7.24±2.28 as per a study by Bhaveshaikh et al. and Lalwani et al., respectively [12,13]. The difference could be because our study was done only in medicine ward where comparatively higher number of drugs is used where as these studies included all other departments as well. In spite of the encouragement from policy-makers and various benefits like low cost of drug therapy, increase patient's adherence and equivalent therapeutic benefits as brand name alternatives generic prescribing is not a common practice in India [14]. In our study, more than 86.5% prescriptions were by brand names which was comparable to other studies, where percentage of drugs by generic names were much lower [12,15]. About 20% of the formulations used in our study were FDCs which was more as compared to 4.9% and 10.82% [12,13]. In elderly with renal and hepatic dysfunction, FDCs may lead to unnecessary and prolonged exposure to drugs and increase risk of drug toxicity [12]. Drugs acting on alimentary tract (22.1%), followed by anti-microbial agents (18.4%), respiratory system (14.7%), and cardiovascular system (9.8%) were the most were commonly prescribed class of drugs, which was comparable to a study done by Nataraj and Bharathi in South India [16]. Overall, 60.5% of the total drugs prescribed were from the NLEMs 2015. Adherence to the list was most commonly seen with hormones (94.4%) and least with respiratory system drugs (31.1%). The understanding of concept of essential medicines and their availability to different sections of society needs to be tested. Around 76.3% of prescriptions had a drug prescribed as an injection. The high percentage of injectables was quite explainable since this was an inpatient study with patients mostly having serious and acute illnesses.
Based on AGS Beers criteria 2019, 369 out of 2683 (13.8%) drugs prescribed in our study were classified as PIM, which was lower than that reported (37.76%) in studies by Bhaveshaikh et al., which used Beers criteria 2012 for assessment [12]. Another study carried out in North Cyprus reported a prevalence of 16.9% PIM as determined by Beers Criteria 2015 [6]. Total 22%, elderly patients received potentially inappropriate prescription of at least one drug which was comparable (23.59%) to a study done by Zaveri et al. [7]. Our value was much lower as compared (76.6%) to a study done by Khamis et al. using Beers Criteria 2015 [6].
Studies to identify the factors for high prevalence of PIM have reported many factors which include multiple diseases, polypharmacy, easy access to medications, both over-the counter drug (OTC) and non-OTC drugs, multiple different hospitalizations with lack of geriatric specialty clinics and possibly the lack of medication review services by pharmacists, or other qualified health-care providers [6].

CONCLUSION
This study suggests that use of PIMs is common in elderly patients, some of them associated with high degree of risk in terms of worsening of the co-morbidity or drug-drug interactions. High prevalence of inappropriate prescribing of medicines in elderly people is associated with various health outcomes such as increased morbidity and mortality, increased cost of treatment, and decreased quality of life. The limitation of our study is that we have considered patients admitted to only Internal medicine ward. More studies in other specialties are necessary to know the prevalence of inappropriate prescribing of medicines in elderly people so as to sensitize the practitioners to this important public health issue and to develop rational prescribing in elderly.