探討健保降血糖藥品之價量變動與市場競爭

Abstract

目的：檢視不同ATC層級之降血糖藥物與類別(單源藥品、多源藥品、BA/BE學名藥及一般學名藥)，藥品之總支出費用及總DDD量變動之趨勢；利用物價指數及價量公式，藉以了解健保給付用藥中降血糖用藥變動幅度；並深入探討口服降血糖市場競爭與藥價調整前後之變化。 方法：本研究為橫斷式研究設計，以2004-2006年全民健康保險門診、住院及特約藥局申報總檔進行分析；研究對象為所有健保給付且有使用之降血糖藥品。利用不同物價指數計算方式 (拉氏、斐氏及費氏物價指數) 與價量公式，計算ATC分類及藥品類別之市場變化。針對口服降血糖藥品市場中之競爭度則以廠商家數、HHI及CR4為指標，探討特定藥品類別之情形。而藥價調整前後對於市場之變化則以價量變動公式來計算。 結果： 2004-2006年間，降血糖用藥總藥品支出為55-65億，費用平均年增率為7.28%；DDD用量平均年增率則以8.10%向上攀升。近年來對於血糖控制標準提高且在Metformin的評價有升高的趨勢，因此也反映在DDD總用量方面。而Sulfonamides第三代的Glimepiride成長快速且有逐漸取代第二代的Glibenclamide及Gliclazide的趨勢。高單價之Thiazolidinediones類中，Avandia®在為降血糖單一藥物費用最高之藥品，但由於有加重心血管疾病及價格之考量而造成2004-2006年間總費用降低7%；而Actos®，雖然研究期間開始有學名藥廠進入市場，但總費用上仍然大幅度攀升46%不受影響。選取各類別前90%費用、DU90%及所有單源原廠之品項之聯集作為建立藥品物價指數為最佳選擇。以2004年為基期年，2005年拉氏指數總體降血糖藥物的平均單價上漲率為1.07%與2004年相比2006年上漲率為3.66%。而藥費成長因素主要來自於用量的增加，並非藥品價格的成長。經過多次的藥價調整及市場競爭，多源原廠及BA/BE學名藥平均價格相當，但似乎BA/BE學名藥有漸漸替代多源原廠的趨勢。深入評估藥價調整前後市場之變化，由於市場的不透明性因此無法定論藥價調整幅度與單一藥品項之市場趨勢，但可以明顯看出醫院層級愈高，藥品轉換愈低。 結論：建立藥品物價指數及價量變動模型為瞭解藥物利用趨勢與幅度良好的指標。藥價調整對於市場影響變動值得後續研究以釐清之。

Objectives：To describe the trend and to decompose antidiabetes drug spending in Taiwan between 2004 and 2006. Also, to examine how the market react associated with pharmaceutical price adjustment on September 1st, 2005. Method：By analysis data obtained from Taiwan National Health Insurance Research Database (NHRID), this study shows changes in antidiabetes drug utilization for 4 drug categories: single-source brand-name drugs, multiple-source brand-name drugs, BA/BE generic drugs and generic drugs. According to anatomical therapeutic chemical (ATC) classification system group, the study further applied to Consumer Price Index (CPI) to explain pharmaceutical price index (PPI) and total spending growth was disaggrated into price, volume (expressed in Defined Daily Dose), and mix effect factors. Result：Antidiabetes drug expenditure in Taiwan grew from $NT 0.55 billion in 2004 to $NT 0.65 billion in 2006, equivalent to 7.28 % annual growth rate in amount base and 8.10% in DDD base. Set year 2004 as a baseline and choosing top 90% sales and DU90% drug item for calculating PPI, and the result is antidiabetes drug’s PPI in year 2005 is 1.07% and 2006 is 3.66%. The primary divers of this expenditure growth were treatment expansion, and substitution. Since the generic-to-brand price ratio is relatively high in Taiwan, which create an incentive for healthcare institutes to prescribe more generics in order to receive a higher profit margin, BA/BE generic drugs are gradually taken over the market. The pharmaceutical price adjustment action by the Bureau has great influence to the market; in particular, the generic substation became more active in regional and area hospitals. Conclusion：Findings suggest the main driving force behind the increase in drug spending was increased volume of drugs prescribed.