Clinical Epidemiology and Health Economy Unit, Department of Orthopedic Surgery, University Hospital Carl Gustav Carus, Medical Faculty of the Technical University of Dresden, Germany.
Eur J Med Res. 2009;14(2):76-84. doi: 10.1186/2047-783x-14-2-76.
Total knee arthroplasty (TKA) is an effective, but also cost-intensive health care procedure for the elderly. Furthermore, bearing demographic changes in Western Europe in mind, TKA-associated financial investment for health care insurers will increase notably and thereby catalyze discussions on ressource allocation to Orthopedic surgery. To derive a quantitative rationale for such discussions within Western Europe's health care systems, a prospective assessment of both the benefit of TKA from a patient's perspective as well as its cost effectiveness from a health care insurer's perspective was implemented.
A prospective cost effectiveness trial recruited a total of 65 patients (60% females), who underwent TKA in 2006; median age of patients was 66 years (interquartile range 61-74 years). Before and three months after surgery patients were interviewed by means of the EuroQol-5D and the WOMAC questionnaires to assess their individual benefit due to TKA and the subsequent inpatient rehabilitation. Both questionnaires' benefit estimates were transformed into the number of gained quality adjusted life years (QALYs). Total direct cost estimates for the overall care were based on German DRG and rehabilitation cost rates (Euro). The primary clinical endpoint of the investigation was the individual number of QALYs gained by TKA based on the WOMAC interview; the primary health economic endpoint was the marginal cost effectiveness ratio (MCER) relating the costs to the associated gain in quality of life (Euro/QALY).
Total direct costs for the overall procedure were estimed 9549 Euro in median. The WOMAC based interview revealed an overall gain of 4.59 QALYs (interquartile range 2.39-6.21 QALYs), resulting in marginal costs of 1795 Euro/QALY (1488-3288 Euro/QALY). The corresponding EuroQol based estimates were 2.93 QALYs (1.75-5.59 QALYs) and 3063 Euro/QALY (1613-5291 Euro/QALY). Logistic regression modelling identified the patients' age as the primary determinant of cost effectiveness (Likelihood Ratio p = 0.006): patients younger than 60 years showed a median gain of 6.45 QALYs and median marginal costs of 1463 Euro/QALY, patients between 60-70 years 5.47 QALYs and 1744 Euro/QALY, patients older than 70 years 2.76 QALYs and 3186 Euro/QALY.
TKA was proven to be cost effective from a health care insurer's perspective, although its marginal costs notably increased with increasing age. Note, however, that this age-related gradient in marginal cost effectiveness is of comparable order as the changes in cost effectiveness due to variation of the underlying assessment instrument.
全膝关节置换术（TKA）是一种针对老年人的有效但成本较高的医疗程序。此外，考虑到西欧人口结构的变化，医疗保险公司对 TKA 的相关财务投资将显著增加，从而引发了关于骨科手术资源分配的讨论。为了在西欧医疗体系内为这些讨论提供量化依据，我们前瞻性地评估了 TKA 从患者角度的获益和从医疗保险公司角度的成本效益。
前瞻性成本效益试验共招募了 65 名（60%为女性）接受 2006 年 TKA 的患者；患者的中位年龄为 66 岁（四分位距 61-74 岁）。在手术前和术后 3 个月，通过 EuroQol-5D 和 WOMAC 问卷对患者进行访谈，以评估他们因 TKA 而获得的个人获益以及随后的住院康复情况。两个问卷的获益估计都转化为获得的质量调整生命年（QALY）数。总体护理的直接总成本基于德国 DRG 和康复费用率（欧元）。研究的主要临床终点是基于 WOMAC 访谈的 TKA 获得的个人 QALY 数；主要的健康经济学终点是与生活质量相关的边际成本效益比（MCER）（欧元/QALY）。
总体治疗过程的直接总成本中位数为 9549 欧元。基于 WOMAC 的访谈显示，总体获益为 4.59 QALY（四分位距 2.39-6.21 QALY），边际成本为 1795 欧元/QALY（1488-3288 欧元/QALY）。相应的 EuroQol 估计值为 2.93 QALY（1.75-5.59 QALY）和 3063 欧元/QALY（1613-5291 欧元/QALY）。逻辑回归模型确定患者的年龄是成本效益的主要决定因素（似然比 p = 0.006）：年龄小于 60 岁的患者中位获益为 6.45 QALY，边际成本为 1463 欧元/QALY；年龄在 60-70 岁之间的患者中位获益为 5.47 QALY，边际成本为 1744 欧元/QALY；年龄大于 70 岁的患者中位获益为 2.76 QALY，边际成本为 3186 欧元/QALY。
从医疗保险公司的角度来看，TKA 具有成本效益，但随着年龄的增长，其边际成本显著增加。然而，需要注意的是，这种与年龄相关的边际成本效益梯度与由于基本评估工具的变化而导致的成本效益变化处于相同的数量级。
