Department of Pharmacy and Therapeutics, School of Pharmacy, University of Pittsburgh, 3501 Terrace St, 637 Salk Hall, Pittsburgh, PA 15261. Email:
Am J Manag Care. 2019 Jul;25(7):348-352.
To evaluate how changes in generic drug prices and the incidence of abrupt price increases varied with the number of manufacturers supplying each drug.
Analysis of 2005 to 2016 monthly wholesale acquisition costs (WACs) and University of Pittsburgh Medical Center Health Plan counts of pharmacy claims for National Drug Codes (NDCs) for generic drugs.
Each year, NDCs were categorized according to the number of manufacturers offering each combination of active ingredient and dosage form: 1 to 3, 4 to 7, and more than 7. For every month from January 2006 to January 2017, we estimated the 12-month change in WAC (eg, 12-month change in January 2006 was calculated as the difference in WAC between January 2006 and January 2005, divided by the WAC in January 2005), before and after weighting each NDC by counts of pharmacy claims. We evaluated the proportion of NDCs that had large price increases, greater than 20%, 50%, 100%, and 500% within a year.
Before 2010, price changes were higher for drugs supplied by a lower number of manufacturers; however, after 2010, prices increased sharply, and drugs supplied by 4 to 7 manufacturers showed increases similar to or higher than those supplied by 1 to 3. In 2013, prices increased by an average of 29% for drugs supplied by 1 to 3 and 4 to 7 manufacturers, and 10% for more than 7. Price changes increased after weighting by counts of pharmacy claims, demonstrating that price increases disproportionately affected widely used drugs. The proportion of NDCs from drugs supplied by 1 to 3 manufacturers that doubled in price within a year was 3.6 times higher in 2012 to 2015 than in 2005 to 2009 (4.6% vs 1.3%, respectively).
Increases in generic drug prices are concerning because they affected widely used drugs and suggest that generic drug prices may be increasingly insensitive to competition.
评估药品通用名价格变化和大幅涨价发生率随供应每种药物的制造商数量变化的情况。
对 2005 年至 2016 年每月药品批发采购成本（WAC）和匹兹堡大学医学中心健康计划的药品通用名（NDC）药房配药数量进行分析。
每年根据每种活性成分和剂型组合的制造商数量对 NDC 进行分类：1 至 3 个、4 至 7 个和 7 个以上。对于 2006 年 1 月至 2017 年 1 月的每个月，我们根据药房配药数量对 WAC 的 12 个月变化进行估计（例如，2006 年 1 月的 12 个月变化是通过 2006 年 1 月与 2005 年 1 月的 WAC 之间的差异除以 2005 年 1 月的 WAC 得出的），然后对每个 NDC 进行加权。我们评估了一年内价格涨幅超过 20%、50%、100%和 500%的 NDC 比例。
2010 年前，供应药物的制造商数量越少，价格变化幅度越大；然而，2010 年后，价格急剧上涨，供应 4 至 7 个制造商的药物的涨幅与供应 1 至 3 个制造商的药物涨幅相似或更高。2013 年，供应 1 至 3 个和 4 至 7 个制造商的药物价格平均上涨 29%，供应 7 个以上制造商的药物价格上涨 10%。经过药房配药数量加权后，价格变化更大，表明价格上涨不成比例地影响了广泛使用的药物。2012 年至 2015 年，供应 1 至 3 个制造商的 NDC 价格翻倍的比例是 2005 年至 2009 年的 3.6 倍（分别为 4.6%和 1.3%）。
通用名药品价格上涨令人担忧，因为它们影响了广泛使用的药品，这表明通用名药品价格可能对竞争的敏感度越来越低。
