Hirth R A, Held P J, Orzol S M, Dor A
Department of Health Management and Policy, University of Michigan School of Public Health, Ann Arbor 48109-2029, USA.
Health Serv Res. 1999 Feb;33(6):1567-92.
To evaluate the effects of case mix, practice patterns, features of the payment system, and facility characteristics on the cost of dialysis.
DATA SOURCES/STUDY SETTING: The nationally representative sample of dialysis units in the 1991 U.S. Renal Data System's Case Mix Adequacy (CMA) Study. The CMA data were merged with data from Medicare Cost Reports, HCFA facility surveys, and HCFA's end-stage renal disease patient registry.
We estimated a statistical cost function to examine the determinants of costs at the dialysis unit level.
The relationship between case mix and costs was generally weak. However, dialysis practices (type of dialysis membrane, membrane reuse policy, and treatment duration) did have a significant effect on costs. Further, facilities whose payment was constrained by HCFA's ceiling on the adjustment for area wage rates incurred higher costs than unconstrained facilities. The costs of hospital-based units were considerably higher than those of freestanding units. Among chain units, only members of one of the largest national chains exhibited significant cost savings relative to independent facilities.
Little evidence showed that adjusting dialysis payment to account for differences in case mix across facilities would be necessary to ensure access to care for high-cost patients or to reimburse facilities equitably for their costs. However, current efforts to increase dose of dialysis may require higher payments. Longer treatments appear to be the most economical method of increasing the dose of dialysis. Switching to more expensive types of dialysis membranes was a more costly means of increasing dose and hence must be justified by benefits beyond those of higher dose. Reusing membranes saved money, but the savings were insufficient to offset the costs associated with using more expensive membranes. Most, but not all, of the higher costs observed in hospital-based units appear to reflect overhead cost allocation rather than a difference in real resources devoted to treatment. The economies experienced by the largest chains may provide an explanation for their recent growth in market share. The heterogeneity of results by chain size implies that characterizing units using a simple chain status indicator variable is inadequate. Cost differences by facility type and the effects of the ongoing growth of large chains are worthy of continued monitoring to inform both payment policy and antitrust enforcement.
评估病例组合、医疗实践模式、支付系统特征以及机构特征对透析成本的影响。
数据来源/研究背景：1991年美国肾脏数据系统病例组合适当性（CMA）研究中具有全国代表性的透析单位样本。CMA数据与医疗保险成本报告、医疗保健财务管理局（HCFA）机构调查以及HCFA的终末期肾病患者登记数据合并。
我们估计了一个统计成本函数，以研究透析单位层面成本的决定因素。
病例组合与成本之间的关系通常较弱。然而，透析实践（透析膜类型、膜复用政策和治疗时长）确实对成本有显著影响。此外，支付受HCFA地区工资率调整上限限制的机构，其成本高于未受限制的机构。医院附属单位的成本显著高于独立单位。在连锁单位中，只有最大的全国性连锁之一的成员相对于独立机构表现出显著的成本节约。
几乎没有证据表明，为确保高成本患者获得医疗服务或公平补偿机构成本，有必要根据各机构病例组合的差异调整透析支付。然而，目前增加透析剂量的努力可能需要更高的支付。更长的治疗似乎是增加透析剂量最经济的方法。改用更昂贵的透析膜类型是增加剂量成本更高的方式，因此必须以高于更高剂量所带来的益处来证明其合理性。复用膜节省了资金，但节省的资金不足以抵消使用更昂贵膜所产生的成本。在医院附属单位观察到的大部分（但并非全部）较高成本似乎反映了间接成本分摊，而非用于治疗的实际资源差异。最大连锁机构所实现的规模经济可能解释了它们近期市场份额的增长。不同连锁规模结果的异质性意味着，使用简单的连锁状态指标变量来描述单位是不够的。机构类型导致的成本差异以及大型连锁机构持续增长的影响值得持续监测，以为支付政策和反垄断执法提供参考。
