慢性病老年病人門診潛在性不適當用藥與不良結果之關係

Abstract

研究背景： 病人安全及醫療品質議題日益受到重視，其中用藥安全更是重點目標。對於許多需要靠長期藥物治療之慢性病老人而言，除藥物之取得不虞匱乏外，所用藥物之安全性和適當性需要嚴格把關，以免未蒙其利而反受其害。用於老人用藥適當性之評估工具和研究之方向，大多數著重在盛行率和相關危險因素之探討，而對於不適當用藥是否真的會導致不良結果則文獻仍不多見。 研究目的： 分析門診老年病人之慢性病連續處方箋含有「潛在性不適當藥物」之型態、盛行率和危險因素，並更進一步探討長期使用「潛在性不適當藥物」之不良結果。 研究方法： 本研究為觀察性的世代研究，以2005年3月間於樣本醫院，領取慢性病連續處方箋之門診老年病人為對象。以Beers-2002年評估準則來判斷是否有不適當用藥（一種明確列舉式評估準則），並追蹤病人於同一機構、在2005年3月至9月間之急診、住院和死亡記錄。 結果： 在5,741位老年病人（7,538處方人次）的慢性病連續處方箋中，含有「潛在性不適當藥物」之盛行率為20.97%，其中含有一種「潛在性不適當藥物」的處方佔88.11%，而含有兩種（含）以上「潛在性不適當藥物」之處方也高達11.89%。最常見之「潛在性不適當藥物」屬嚴重度高的藥物中，以抗心律不整藥amiodarone、刺激性瀉劑bisocodyl 、降血壓劑nifedipine 、抗憂鬱劑amitriptyline 和肌肉鬆弛劑chlorzoxazone 及其複方劑為最多。 屬於嚴重度低的藥品則以dipyridamole最頻繁，其次是 doxazosin和 digoxin。 羅吉斯複迴歸分析顯示「潛在性不適當」用藥之相關危險因素包括性別(OR 1.18, 95% CI 1.01 to 1.35)、年齡(OR 1.02, 95% CI 1.01 to 1.03)、慢性病種類數(OR 1.13, 95% CI 1.03 to 1.24)、每張處方之藥物品項數(OR 1.37, 95% CI 1.32 to 1.42)、和同月份內領取之慢性病連續處方箋張數(OR 1.43, 95% CI 1.28 to 1.59)。此外，若與家醫科比較，腎臟內科(OR 4.15, 95% CI 2.81to 6.13)、精神科(OR 2.34, 95% CI 1.41 to 3.87)、外科(OR 2.31, 95% CI 1.64 to 3.24)、風濕免疫科(OR 1.89, 95% CI 1.25 to 2.88)和心臟內科(OR 1.35, 95% CI 1.01 to 1.80)之病人使用不適當藥物的風險比家醫科高。 不良結果之發生率為19.29%，其中急診發生率為10.86%；住院發生率為8.12%而死亡發生率為0.31%。有使用「潛在性不適當藥物」者，其發生急診和住院之機率皆比無使用者高，但與死亡機率則無相關性。有使用者發生急診和死亡時之醫療費用比無使用者高，但住院費用則兩者無差異。 羅吉斯複迴歸分析顯示，病人急診與死亡，與有無使用「潛在性不適當藥物」沒有相關性。但在住院風險方面，除性別、年齡、用藥品項數外，與有無使用「潛在性不適當藥物」有正相關性，有使用者發生住院之風險與無使用者比較，其勝算比是1.62（OR 1.62, 95% CI 1.04 to 2.53）。 結論： 慢性病連續處方箋之老年病人，其處方箋含有「潛在性不適當藥物」高達21%，幾乎每5位門診慢性病連續處方箋之老年病人就有一人會拿到「潛在性不適當藥物」。許多因素皆會增加老年病人使用「潛在性不適當藥物」之機率，而「潛在性不適當藥物」的使用還會增加老年病人住院之風險。

BACKGROUND: The issue of patient safety and the quality of healthcare is of great concern, and the important target is the safety of medication use. For elderly patients with chronic illnesses, due to a number of medications needed for long-term use, the safety and the appropriateness of medication use should be of upmost concern. Previous studies using different measures to evaluate medication appropriateness among elderly had indicated the prevalence and the risk factors of inappropriate use, but little information is known about the relationship between inappropriate medication use and their adverse outcomes. OBJECTIVE: To identify the prevalence and the risk factors of potentially inappropriate medication use among elderly ambulatory patients with chronic diseases, and to explore the possible associations between potentially inappropriate medication use and the risk of developing adverse outcomes. METHODS: Ambulatory elderly patients who had 3-month refill prescription in a medical center were recruited consecutively during the enrollment period （March 1-31, 2005）. Data of the adverse outcomes including emergency visits, hospitalizations and mortality for the coming 6 months after inclusion were collected. Beer criteria-2002 （an explicit criteria）was used to judge the appropriateness in this observational cohort study. RESULTS: The prevalence was 20.97%（incidents in a total of 5,741 patients or in 7,538 visits）, where 88.11% elderly received one inappropriate medication and other 11.89% had two or more inappropriate medications. The most frequent inappropriate medication of high severity were amiodarone, bisacodyl, nifedipine, amitriptyline and chlorzoxazone；those of low severity were dipyridamole, doxazosin and digoxin. Logistic regression revealed that gender (OR 1.18, 95% CI 1.01 to 1.35), age (OR 1.02, 95% CI 1.01 to 1.03), the number of chronic diseases (OR 1.13, 95% CI 1.03 to 1.24), the number of medications taken (OR 1.37, 95% CI 1.32 to 1.42), and the number of refill prescriptions received within the same month (OR 1.43, 95% CI 1.28 to 1.59), all significantly increased the likelihood of receiving inappropriate medications. Otherwise, when family physicians were used as the reference, the patients receiving prescriptions from nephrologist (OR 4.15, 95% CI 2.81to 6.13), psychiatrist (OR 2.34, 95% CI 1.41 to 3.87), surgeon (OR 2.31, 95% CI 1.64 to 3.24), rheumatologist (OR 1.89, 95% CI 1.25 to 2.88), and cardiologist (OR 1.35, 95% CI 1.01 to 1.80) were significantly in higher risk to have inappropriate medications. The incidence of adverse outcomes within the study period was 19.29%, where 10.86% patients visited the emergency department, 8.12% patients hospitalized and 0.31% patients died. Inappropriate medication use increased the likelihood of emergency visit and hospitalization, but with no correlation in mortality. Inappropriate medication use also increased the expenditures of emergency visit and mortality, but no difference was seen in hospitalization. Logistic regression revealed that inappropriate medication use did not increase the risk of emergency visit or mortality, but had significant association with hospitalization（OR 1.62, 95% CI 1.04 to 2.53）. CONCLUSIONS: Potentially inappropriate medication use was common among elderly ambulatory patients of chronic diseases. Many factors were found to increase the risk of receiving inappropriate medications among elderly of chronic diseases. Inappropriate medication use is associated with a higher risk of hospitalization.