INTRODUCTION
Aged patients have multiple diseases and so take many medications. There are many side effects of medication itself and drug-drug interactions, so physicians should consider these when they prescribe for elderly patients. Improved prescribing in the elderly tool (IPET) and Beers' criteria have been widely used as screening tools of inappropriate prescription to elderly patients,1) but IPET does not contain many drugs frequently used for elderly patients, and Beers' criteria contains drugs not used in Korea. Some researchers found these tools were limited in discovering inappropriate prescription.2,3)
O'Mahony and Gallagher4) suggested the need for new criteria. A panel composed of 18 Irish and British experts of geriatrics, clinical pharmacology, geriatric psychology, and primary medicine made a list of 65 medications that should not be prescribed for specific diseases and 22 medications that should be prescribed for specific conditions. These are the Screening Tool of Older Persons' potentially inappropriate Prescriptions (STOPP)/Screening Tool to Alert doctors to the Right Treatment (START) criteria, developed to overcome the limitations of previous IPET and Beers' criteria (Appendix 1).3) In this study, we reviewed the diseases and medications of the elderly patients admitted to Inha University Hospital, and analyzed the prescriptions by applying the STOPP/START criteria.
METHODS
1. Study Population
Enrolled in this study were 117 patients 65 years or older admitted to any department in Inha University Hospital in Incheon due to pneumonia from the 1st of January 2012 to 31 March 2012. Patients with cancer stage 4, severely ill, cardiopulmonary resuscitation (CPR) prohibition request patients, and patients who had received CPR were excluded. We excluded patients who had received or refused CPR and terminal stage cancer patients because in those cases physicians may have knowingly used inappropriate medication necessarily or may not use needed long-term medication due to short life expectancy.
2. Research Methods
We reviewed patients' sex, age, height, weight, past medical history, recent diagnosis, and medications they took before and after administration based on medical records. Regardless of formula, we reviewed all oral, intravenous and inhaled medications, and checked dosage and mode of use. We checked serum creatinine levels and calculated glomerular filtration rate.
Based on the information collected, we checked potentially inappropriate medications (PIMs) and potential prescribing omissions (PPOs) by applying each item of the STOPP/START criteria to the patients. This report is a retrospective study based on medical records, and was approved by institutional review board of Inha University Hospital, and informed consent was waived.
RESULTS
1. Characteristics of Study Population
Of the 117 research subjects, 65 people were male (55%) and 52 were female (45%), with a mean age of 77.4 years. The most common age group was from 75 to 84, 58 persons (56%), followed by age group from 65 to 74, 42 persons (34%). There were 17 people over age 85 (10%). The oldest age was 95 years old; there were two such people. Hypertension was the most common disease, and 71 patients suffered from it (60.7% of the patients). Diabetes (29.0%) and ischemic heart disease (20.5%) followed hypertension. The average number of drugs per patient was 14, with a range from 6 to 25 (Table 1).
2. Application of Screening Tool of Older Persons' Potentially Inappropriate Prescriptions Criteria
Twenty-four patients who had 29 PIMs were identified by using the STOPP criteria. Males had PIMs (21.5%) slightly more often than females (19.2%). Twenty people had one inappropriate prescription (23.0%), and four people had two or more inappropriate prescriptions (3.3%) (Table 2). Inappropriate prescriptions were found in 12 lists by 65 criteria.
The most frequent inappropriate prescription was for cardiovascular system medications (11 PIMs, 37.9%), followed by drugs whose primary effect is on the urogenital (10 PIMs, 34.5%) and gastrointestinal system (5 PIMs, 17.2%). Among the cardiovascular drugs, calcium channel blockers given to patients with chronic constipation was the most common PIMs (5 PIMs, 17.2%), and among genitourinary system drugs, antimuscarinic agents given to chronic constipation patients was the most common (5 PIMs, 17.2%). One inappropriate prescription was found each for central nervous system drugs, musculoskeletal system drugs, and medications that can be harmful to patients hurt from a fall (Table 3).
3. Application of Screening Tool to Alert Doctors to the Right Treatment Criteria
PPOs, which are absolutely necessary but not given to the patients, included 46 cases in 31 patients found by the START criteria. PPOs were more common in men (29.2%) than in women (23.0%). Twenty patients had one drug prescription omission, and one patient had four drug omissions (Table 4). PPOs were found in 12 lists between 22 criteria.
Cardiovascular drugs accounted for most of the PPOs (17 PPOs, 37.0%), and of those, aspirin (5 PPOs, 10.9%) and statins (5 PPOs, 10.9%) are the most commonly omitted drugs. In the field of the musculoskeletal system, bisphosphonates are the most commonly omitted drugs (6 PPOs, 13.0%). Statins were one of the most commonly omitted drugs in the cardiovascular and endocrinology system (10 PPOs, 22.2%). There were no omitted central nervous system medications (Table 5).
DISCUSSION
According to the National Health and Nutrition Examination Survey III, over half of patients between 65 to 74 years old take more than two medications, and 12% take over five. Over 75 years of age, more than 60% take two or more medications, and 16% take more than five medications.5) A study conducted on 20,575 outpatients and 4,519 inpatients at one university hospital in Korea reported that outpatients were prescribed an average of six medications, and inpatients received 18.6)
Generally, elderly patients have multiple chronic diseases requiring a number of medications, and hospital admission will often more than double their usual amount. Therefore, physicians should pay close attention to medical history and current medication when adding a new medication for elderly patients.
In our study PIMs were found in 20.5% of patients according to the STOPP criteria. This is similar to the 21.4% in 1,329 elderly people who visited three general practices in Ireland.2) The fact that about one fifth of patients admitted to a university hospital where they are cared for by so many doctors and nurses have more than one inappropriate prescription is an important message to physicians.
Prescription for patients who had chronic constipation was the most common inappropriately prescribed medication, with 15 instances found in the current study. Possible explanations include that the physician ignored conditions such as constipation that could disturb the patient's quality of life, or the physician did not know that calcium channel blocker (CCB) could aggravate constipation, or that the patient has constipation. Another possible explanation is that though the physician knew it is possible that CCBs worsen constipation, important heart drugs could not be withheld.
One study that analyzed inappropriate drug prescriptions in elderly patients, using Beers' criteria intended for outpatients, found that of 20,575 people and the elderly of the 4,519 people admitted to a university hospital in 2004, 27.8% of patients received inappropriate medications.6) That is higher than the percentage of 20.5 of this study, but lower than other studies2) using the STOPP criteria. Perhaps because only hospitalized pneumonia patients are considered in this study, the percentage of inappropriate prescription may be lower than in other studies.
PPOs reviewed using the START criteria was 26.5%, slightly higher than the 22.7% in the Ireland study.2) Statins were the most commonly omitted drugs. In the START criteria, statins are recommended for patients who have coronary artery, cerebrovascular, and peripheral vascular disease if they can do normal activities of daily life and their life expectancy is more than five years. Diabetes patients are also recommended to use statins if they have major risk factors for cardiovascular disease. However, the insurance guidelines of Korea allow the prescription only if the total blood cholesterol is more than 220 mg/dL, or triglycerides are 200 mg/dL or more, even with a cardiovascular risk factor, so it seems that there are many prescription omissions of statins. There is a need to develop new guidelines about inappropriate prescription for elderly patients in Korea.
This study has some limitations. First, it is impossible to generalize to the entire elderly population since this study was restricted to pneumonia patients admitted to a university hospital. Second, it is possible that there are omissions of patients' past medical history and medications, because we checked the patients' history and drugs only through the medical records created by the doctors or nurses.
However, this study is significant in that it is the first to describe the prescription of inappropriate drugs in elderly patients by using the STOPP/START criteria in Korea. In addition, while the role of previous tools was just to find inappropriate prescriptions, this study attempted to find potential prescription omissions using a new tool called START.
Analytic tools such as STOPP/START criteria are not the best way to find inappropriate prescription and potential omission for elderly patients. There might be many cases when a physician needs to use medication that nevertheless will be flagged as inappropriate. Prescription that meets each clinical situation is important, but if the physician understands these criteria and uses them properly, it should help minimize inappropriate prescriptions and reduce the side effects.
Hereafter, conducting a long term study using STOPP/START criteria including not only the patients of a university hospital but also of a convalescent hospital and primary clinic is needed. We think there is a need to develop appropriate criteria to match the actual conditions in Korea.
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