Department of Pharmacology and Therapeutics, State University of Maringá, Avenue Colombo 5790, 87020-290, Maringá, PR, Brazil.
Eur J Clin Pharmacol. 2012 Dec;68(12):1667-76. doi: 10.1007/s00228-012-1309-3. Epub 2012 May 30.
Although the prevalence of drug-drug interactions (DDIs) in elderly outpatients is high, many potential DDIs do not have any actual clinical effect, and data on the occurrence of DDI-related adverse drug reactions (ADRs) in elderly outpatients are scarce. This study aimed to determine the incidence and characteristics of DDI-related ADRs among elderly outpatients as well as the factors associated with these reactions.
A prospective cohort study was conducted between 1 November 2010 and 31 November 2011 in the primary public health system of the Ourinhos micro-region, Brazil. Patients aged ≥60 years with at least one potential DDI were eligible for inclusion. Causality, severity, and preventability of the DDI-related ADRs were assessed independently by four clinicians using validated methods; data were analysed using descriptive analysis and multiple logistic regression.
A total of 433 patients completed the study. The incidence of DDI-related ADRs was 6 % (n = 30). Warfarin was the most commonly involved drug (37 % cases), followed by acetylsalicylic acid (17 %), digoxin (17 %), and spironolactone (17 %). Gastrointestinal bleeding occurred in 37 % of the DDI-related ADR cases, followed by hyperkalemia (17 %) and myopathy (13 %). The multiple logistic regression showed that age ≥80 years [odds ratio (OR) 4.4; 95 % confidence interval (CI) 3.0-6.1, p < 0.01], a Charlson comorbidity index ≥4 (OR 1.3; 95 % CI 1.1-1.8, p < 0.01), consumption of five or more drugs (OR 2.7; 95 % CI 1.9-3.1, p < 0.01), and the use of warfarin (OR 1.7; 95 % CI1.1-1.9, p < 0.01) were associated with the occurrence of DDI-related ADRs. With regard to severity, approximately 37 % of the DDI-related ADRs detected in our cohort necessitated hospital admission. All DDI-related ADRs could have been avoided (87 % were ameliorable and 13 % were preventable). The incidence of ADRs not related to DDIs was 10 % (n = 44).
The incidence of DDI-related ADRs in elderly outpatients is high; most events presented important clinical consequences and were preventable or ameliorable.
尽管老年门诊患者药物-药物相互作用（DDI）的发生率很高，但许多潜在的 DDI 实际上并没有任何临床影响，关于老年门诊患者 DDI 相关不良反应（ADR）发生的数据也很有限。本研究旨在确定老年门诊患者 DDI 相关 ADR 的发生率和特征，以及与这些反应相关的因素。
这是一项于 2010 年 11 月 1 日至 2011 年 11 月 31 日在巴西 Ourinhos 微观地区初级公共卫生系统中进行的前瞻性队列研究。年龄≥60 岁且至少有一种潜在 DDI 的患者符合纳入标准。四名临床医生使用经过验证的方法独立评估 DDI 相关 ADR 的因果关系、严重程度和可预防程度；使用描述性分析和多因素逻辑回归对数据进行分析。
共有 433 名患者完成了研究。DDI 相关 ADR 的发生率为 6%（n=30）。华法林是最常涉及的药物（37%的病例），其次是乙酰水杨酸（17%）、地高辛（17%）和螺内酯（17%）。37%的 DDI 相关 ADR 病例出现胃肠道出血，其次是高钾血症（17%）和肌病（13%）。多因素逻辑回归显示，年龄≥80 岁（比值比[OR]4.4；95%置信区间[CI]3.0-6.1，p<0.01）、Charlson 合并症指数≥4（OR 1.3；95%CI 1.1-1.8，p<0.01）、使用五种或更多药物（OR 2.7；95%CI 1.9-3.1，p<0.01）和使用华法林（OR 1.7；95%CI 1.1-1.9，p<0.01）与 DDI 相关 ADR 的发生有关。关于严重程度，我们队列中检测到的约 37%的 DDI 相关 ADR 需要住院治疗。所有 DDI 相关 ADR 都可以避免（87%是可改善的，13%是可预防的）。与 DDI 无关的 ADR 发生率为 10%（n=44）。
老年门诊患者 DDI 相关 ADR 的发生率较高；大多数事件具有重要的临床后果，且可预防或可改善。
