過程面照護品質對服務量與照護成效間關係的中介影響效果之探討─以糖尿病醫療給付改善方案照護情形為例

Exploring the mediating effect of process of care on the volume-outcome relationship for diabetes care: An example in Pay-For-Performance

魏嘉琦(Chia-Chi Wei)

指導教授 ： 鍾國彪

共同指導教授 ： 賴美淑(Mei-Shu Lai)

國立臺灣大學/公共衛生學院/健康政策與管理研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.02256

摘要

研究背景：服務量與成效間的關係一直備受關注與討論，在外科手術治療領域上的相關研究不勝枚舉，且也經由諸多研究證實，在許多手術治療程序中，存在著服務量越高、治療成效越好的正向關係。然而卻鮮少有研究探討在照護過程複雜的慢性病領域，如糖尿病，服務量對照護成效是否有其重要意涵存在？且過去研究亦提出過程面照護品質可能會影響服務量與成效之間的關係，但仍未能對這三者之間的關係與意涵提出明確的解釋。
研究目的：本研究以糖尿病此慢性疾病為探討主題，並以糖尿病醫療給付改善方案的照護情形為例，除了探討醫師服務量對糖尿病照護成效是否為一項重要因子之外，並首重以「中介模式」的去探討服務量、過程面照護品質、照護成效─這三個分別帶有結構面、過程面、結果面品質之概念的變項間，是否存在著潛在的影響機制，了解過程面照護品質是否對服務量與照護成效之間關係帶來中介的影響效果，對過去所無法釐清之服務量與照護成效間的關係，提出進一步解釋。
研究方法：本研究為橫斷性研究，以臺灣糖尿病醫療給付改善方案照護情形為例，採用次級資料分析，利用2008年全民健康保險資料庫(NHID)以及健保資訊網服務系統(VPN)，計算這段期間，醫師所照護之糖尿病醫療給付改善方案病人數為醫師服務量；以其所照護的這群病人於當年度糖化血色素檢查平均值達到控制目標(HbA1C<7.0%)的比率，作為其照護成效的衡量；其所照護的這群病人於當年度執行兩次以上糖化血色素檢查的比率，作為其過程面照護品質的衡量。以複迴歸分析分別驗證服務量對過程面照護品質、照護成效之影響，再進一步以中介效果之驗證方式，探討過程面照護品質是否對服務量與照護成效間的關係帶來中介的影響效果。
研究結果：在控制醫師與病人特性後，醫師服務量與照護成效、過程面照護品質皆有顯著正向關係，服務量越高之醫師，其病人糖化血色素達控制目標的比率也越高；服務量越高之醫師，其病人糖化血色素檢查達執行目標的比率也越高。而過程面照護品質又為醫師服務量與照護成效之間的中介變項，且為完全中介之現象，表示在本研究中，醫師服務量對照護成效的影響效果，其實是間接地透過過程面照護品質所造成的，而此中介效果又會受到病人合併症情形的調節影響。
研究結論：本研究結果支持，在糖尿病醫療給付改善方案的照護情形中，醫師服務量對照護成效確實也有其影響，但此影響乃是透過過程面照護品質所造成的。基於此驗證，推論或許接受較高服務量的醫師之照護，可因為獲得較佳的過程面照護品質，而進而達到較好的照護成效。藉由中介效果的驗證，解釋了服務量是如何影響照護成效，凸顯過程面照護品質的重要性，雖然本研究結果支持服務量與照護成效存在正向關係，但認為光強調服務量仍是不足的，因服務量代表的意涵過於廣泛，因此，仍要確定過程面照護品質佳，乃是更重要的觀念，或許這樣的關係與現象，在強調且重視照護過程的疾病照護領域中，更具有討論意義。

關鍵字

服務量 ； 過程面照護品質 ； 照護成效 ； 糖尿病照護 ； 中介效果

並列摘要

Background: Over the past few years, the relationship of volume and outcome has been widely discussed in many medical conditions, especially in surgical procedures. A lot of studies support that higher volume is associated with better outcome in a number of medical conditions. However, researches has not clearly identified whether a similar association exists for chronic medical condition, such as diabetes care, whether volume also has an important implication is unclear. And past studies have also considered that the process of care may affect the relationship of volume and outcome. But it still cannot explain the meaning and relationship between volume, quality of process and outcome.

Objective: First, this study sought to identify the relationship of physician volume with quality of process and outcome in diabetes care, for Pay-for-Performance Payment Program’s patients cared for by physicians. Second, by using an mediation analysis, this study investigated the volume, process of care and outcome which respectively represent the three dimensions of quality of care─structure, process and outcome, to identify the mechanism underlying the association between volume, quality of process and outcome. Finding out whether quality of process may mediate the relationship of volume and outcome, attempting to clarify the reason why volume is associated with outcome.

Methods: In this cross-sectional study, select the diabetes care in Pay-for-Performance Payment Program as an example and used secondary database from Taiwan’s National Health Insurance Research Database and VPN in 2008. Physicians’ patient volume was calculated based on the number of diabetes patients in Pay-for-Performance Payment Program. Physicians’ outcome performance was the rate of patients whose HbA1C average value was under control among all of the patients. Physicians’ process of care performance was the rate of patients who achieve the performance goal (check HbA1C value twice per year) among all of the patients. Using multiple regression analysis to verify the relationship of physician volume with process of care and outcome. Furthermore, using mediation analysis to verify whether process of care is an mediating variable in the relationship of volume and outcome.

Results: In multiple regression analysis, after adjustment for physician characteristics and patient characteristics, physician volume was positively related to outcome and process of care, and process of care would mediates the relationship of volume and outcome, and it’s a complete mediation effect. In fact, the impact of volume on outcome was through quality of process care, that is, the impact of volume on outcome was indirectly, caused by the process of care. And this mediation effect was moderated by patients’ complications.

Conclusions: This study suggests that, for diabetes care in Pay-for-Performance Payment Program, physicians’ patient volume would affect outcome, but this association is because of process of care performance. Based on this verification, cared for by physicians or hospital with greater numbers of diabetes patients in Pay-for-Performance Payment Program may obtain better process of care, then obtain better outcome. By mediation analysis, explained how the impact of volume on outcome, and highlighted the important of process of care. However, emphasizing volume was insufficient, because the implication of volume is too wide. Thus, emphasizing process of care was a more important concept, and perhaps such a relationship and phenomenon for some medical conditions which more emphasized on the process of care, was the most important point.

並列關鍵字

volume ； process of care ； outcome ； diabetes care ； mediation analysis

參考文獻

Lin, C. C., Lai, M. S., Syu, C. Y., Chang, S. C., & Tseng, F. Y. (2005). Accuracy of diabetes diagnosis in health insurance claims data in Taiwan. Journal of the Formosan Medical Association, 104(3), 157-163.

王庭荃, & 楊長興. (2008). 醫師年資、醫療服務量與消化性潰瘍治療效果之相關研究. 臺灣公共衛生雜誌, 27(1), 57-66.

周碧瑟, 董道興, 李佳琳, 莊紹源, 林敬恆, & 楊南屏. (2002). 台灣地區糖尿病流行病學. 臺灣公共衛生雜誌, 21(2), 83-96.

許碧峰. (2009). 冠狀動脈繞道手術量與療效關係之實證研究. 臺灣公共衛生雜誌, 28(1), 69-77.

蔡明足, 翁林仲, 蔡維河, 蔡景耀, 周歆凱, 林敬恆, & 周碧瑟. (2008). 台灣地區糖尿病病患及其視網膜病變的醫療資源耗用. 臺灣公共衛生雜誌, 27(2), 101-109.