Thompson Wes, Wang Hongwei, Xie Minge, Kolassa John, Rajan Mangala, Tseng Chin-Lin, Crystal Stephen, Zhang Quanwu, Vardi Yehuda, Pogach Leonard, Safford Monika M
Deep South Center on Effectiveness at the Birmingham VA Medical Center and the University of Alabama, 35294, USA.
Health Serv Res. 2005 Dec;40(6 Pt 1):1818-35. doi: 10.1111/j.1475-6773.2005.00439.x.
A1c levels are widely used to assess quality of diabetes care provided by health care systems. Currently, cross-sectional measures are commonly used for such assessments.
To study within-patient longitudinal changes in A1c levels at Veterans Health Administration (VHA) facilities as an alternative to cross-sectional measures of quality of diabetes care.
Longitudinal study using institutional data on individual patient A1c level over time (October 1, 1998-September 30, 2000) with time variant and invariant covariates.
One hundred and twenty-five VHA facilities nationwide, October 1, 1998-September 30, 2000.
Diabetic veteran users with A1c measurement performed using National Glycosylated Hemoglobin Standardization Project certified A1c lab assay methods.
Characteristics unlikely to reflect quality of care, but known to influence A1c levels, demographics, and baseline illness severity.
Monthly change in A1c for average patient cared for at each facility.
The preponderance of facilities showed monthly declines in within-patient A1c over the study period (mean change of -0.0148 A1c units per month, range -0.074 to 0.042). Individual facilities varied in their monthly change, with 105 facilities showing monthly declines (70 significant at .05 level) and 20 showing monthly increases (5 significant at .05 level). Case-mix adjustment resulted in modest changes (mean change of -0.0131 case-mix adjusted A1c units per month, range -0.079 to 0.043). Facilities were ranked from worst to best, with attached 90 percent confidence intervals. Among the bottom 10 ranked facilities, four remained within the bottom decile with 90 percent confidence.
There is substantial variation in facility-level longitudinal changes in A1c levels. We propose that evaluation of change in A1c levels over time can be used as a new measure to reflect quality of care provided to populations of individuals with chronic disease.
糖化血红蛋白（A1c）水平被广泛用于评估医疗保健系统提供的糖尿病护理质量。目前，横断面测量常用于此类评估。
研究退伍军人健康管理局（VHA）设施中患者个体A1c水平的纵向变化，以此作为糖尿病护理质量横断面测量的替代方法。
使用关于个体患者随时间（1998年10月1日至2000年9月30日）的A1c水平的机构数据进行纵向研究，数据包含时变和非时变协变量。
1998年10月1日至2000年9月30日期间，全国125个VHA设施。
使用国家糖化血红蛋白标准化项目认证的A1c实验室检测方法进行A1c测量的糖尿病退伍军人使用者。
不太可能反映护理质量，但已知会影响A1c水平的特征、人口统计学因素和基线疾病严重程度。
每个设施所护理的平均患者的A1c每月变化情况。
在研究期间，大多数设施的患者个体A1c水平每月呈下降趋势（平均每月变化-0.0148个A1c单位，范围为-0.074至0.042）。各设施的每月变化有所不同，105个设施呈每月下降趋势（70个在0.05水平上具有显著性），20个设施呈每月上升趋势（5个在0.05水平上具有显著性）。病例组合调整导致变化不大（病例组合调整后的A1c平均每月变化-0.0131个单位，范围为-0.079至0.043）。设施按从最差到最好的顺序排名，并附有90%的置信区间。在排名最靠后的10个设施中，有4个在90%的置信度下仍处于最低十分位数。
设施层面A1c水平的纵向变化存在很大差异。我们建议，随时间对A1c水平变化的评估可作为一种新的指标，用于反映为慢性病患者群体提供的护理质量。
