The variety of methods for counting medications may lead to confusion when attempting to compare the extent of polypharmacy across different populations. To compare the prevalence estimates of polypharmacy derived from medico-administrative databases, using different methods for counting medications. Data were drawn from the Québec Integrated Chronic Disease Surveillance System. A random sample of 110,000 individuals aged >65 was selected, including only those who were alive and covered by the public drug plan during the one-year follow-up. We used six methods to count medications: #1-cumulative one-year count, #2-average of four quarters' cumulative counts, #3-count on a single day, #4-count of medications used in first and fourth quarters, #5-count weighted by duration of exposure, and #6-count of uninterrupted medication use. Polypharmacy was defined as ≥5 medications. Cohen's Kappa was calculated to assess the level of agreement between the methods. A total of 93,516 (85 %) individuals were included. The prevalence of polypharmacy varied across methods. The highest prevalence was observed with cumulative methods (#1:74.1 %; #2:61.4 %). Single day count (#3:47.6 %), first and fourth quarters count (#4:49.5 %), and weighted count (#5:46.6 %) yielded similar results. The uninterrupted use count yielded the lowest estimate (#6:35.4 %). The weighted method (#5) showed strong agreement with the first and fourth quarters count (#4). Cumulative methods identified higher proportions of younger, less multimorbid individuals compared to other methods. Counting methods significantly affect polypharmacy prevalence estimates, necessitating their consideration when comparing and interpretating results.

中文翻译：

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评估医疗行政数据库中复方用药的药物计数方法的比较分析


当试图比较不同人群的多重用药程度时，多种药物计数方法可能会导致混乱。使用不同的药物计数方法，比较来自医疗管理数据库的多重用药流行率估计。数据来自魁北克综合慢性病监测系统。随机抽取了 110,000 名年龄 > 65 岁的人作为样本，其中仅包括那些在一年的随访期间仍然活着并受到公共药物计划覆盖的人。我们使用六种方法来统计药物：#1-一年累计计数，#2-四个季度累计计数的平均值，#3-单日计数，#4-第一和第四季度使用的药物计数， #5-按暴露时间加权的计数，以及#6-不间断用药的计数。多重用药被定义为≥5种药物。计算 Cohen 的 Kappa 来评估方法之间的一致性程度。总共包括 93,516 名 (85%) 人。多种用药方法的流行率各不相同。采用累积方法观察到的患病率最高（#1：74.1 %；#2：61.4 %）。单日计数 (#3:47.6 %)、第一和第四季度计数 (#4:49.5 %) 和加权计数 (#5:46.6 %) 产生了类似的结果。不间断使用计数得出最低估计值 (#6:35.4 %)。加权方法 (#5) 与第一季度和第四季度的计数 (#4) 非常一致。与其他方法相比，累积方法识别出了更高比例的年轻且多病较少的个体。计数方法显着影响复药流行率估计，因此在比较和解释结果时需要考虑这些方法。