BACKGROUND/RATIONALE:
Ambulatory care sensitive conditions (ACSCs) are those for which related hospitalizations may be avoidable by providing appropriate ambulatory care services. However, the relationship between appropriate, timely ambulatory care and risk for specific hospitalizations has never been demonstrated at the individual level. Diabetes is an ideal disease state in which to study these associations since nationally accepted performance measures for ambulatory care are widely adopted. We will evaluate hospitalizations for uncontrolled diabetes, diabetic ketoacidosis, and lower extremity amputations. These are three of the fourteen adult Prevention Quality Indicators (PQIs) developed and proposed for national implementation by the Agency for Healthcare Research and Quality. However, no one has evaluated outcomes for specific indicators on an individual level basis uisng ambulatory and inpatient data sets.
OBJECTIVE(S):
Aim 1. To operationalize outcome measures: selected ACSC hospitalizations related to diabetes that may be affected by ambulatory processes of care. Aim 2. To investigate associations between patient level factors and ambulatory diabetes care and between patient level factors and the ACSC hospitalizations in Aim 1. Aim 3. To evaluate ambulatory processes of care as the primary exposure and determine the extent to which these processes are multivariately associated with the ACSC hospitalizations defined in Aim 1. Aim 4. To investigate the contribution of institutional and community level factors on the relationship between ambulatory processes of care and ACSC hospitalizations.
METHODS:
The project is a retrospective analysis of all veteran clinical users with diabetes, dually eligible for Medicare in FY97/FY98, who were alive on 9/30/98. Ambulatory care and hospitalizations will be followed for FY99-FY01. The database is derived from multiple sources: VA Healthcare Analysis and Information Group, Veterans Support Center (NCPD); CMS MEDPAR A and MEDPAR B claims data. It was supplemented by the Large Veterans Health Survey.
FINDINGS/RESULTS:
1. Cases of metabolic decompensation averaged more diabetes visits and A1c tests than controls (P<0.001) in the 12 month baseline period; among the high risk, 29.9% of cases made four quarterly visits compared to 26.4% of controls (p<0.001). The inconsistency with the theoretical association between frequency of appropriate ambulatory care and lower MD rates indicates that MD rates may not accurately reflect quality of diabetes care.
2. In 2000, 56.8% of subjects received care from both VHA and Medicare providers. The average proportion of visits to Medicare providers was 0.40 (median 0.38) and the mean HA1c value was 7.36% +/- 1.5. After controlling for endogeneity, a higher proportion of Medicare visits was significantly associated with higher HA1c value. Increasing the proportion of Medicare use to 40% was associated with a 0.23 increase in HA1c values.. Dual-system use was associated with higher HA1c values, suggesting that veterans who chose to receive care outside the integrated VHA system may lower quality care than those who received care exclusively within the system
3. There were 399,603 veterans with diabetes, alive in FY 1998, and without prior major amputations during FY1997-1998 who incurred 3780 incurred major amputations during FY 1999-2000; individuals in the more severe foot-risk group had higher major amputation rates (range: 4.3 to 30.3 per 1000). The percentages of having foot surveillance increased with increasing risk classification group severity: 12.9% (Group 0), 24.7% (Group 1), 44.5% (Group 2), and 60.8 % (Group 3). Our multivariate Cox regression models showed that having foot surveillance reduced the risk of major amputation, but only for patients in Groups 2 and 3. For example, patients in Group 3 who received foot surveillance consistently for 3 calendar quarters were 32% less likely to have major amputations than patients who did not have foot surveillance: (adjusted hazard ratio(AHR)= 0.68; 95% CI: 0.58-0.79); in the same Group 3, those who received 4 quarters of surveillance were 42% less likely to have major amputations (AHR=0.58, 95% CI=0.50-0.68) Our results suggest that foot surveillance may need to be improved and prioritized, and this may results in fewer major amputations.
IMPACT:
1. Cited by the VHA HERC HSRD Web seminar on merged VHA-CMS databases
2. Referenced by Organisation for Economic Co-operation and Development (OECD) in recommendation of the adoption of major amputations as a measure of diabetes quality of care rather than total amputations
(www.oecd.org/dataoecd/28/34/33865546.pdf).
3. Utilized in CDC Diabetes Translation Division Public Health Course
PUBLICATIONS:
Journal Articles
- Maney M, Tseng CL, Safford MM, Miller DR, Pogach LM. Impact of self-reported patient characteristics upon assessment of glycemic control in the Veterans Health Administration. Diabetes Care. 2007; 30(2): 245-51.
- Tseng CL, Rajan M, Miller DR, Hawley G, Crystal S, Xie M, Tiwari A, Safford M, Pogach L. Use of administrative data to risk adjust amputation rates in a national cohort of medicare-enrolled veterans with diabetes. Medical Care. 2005; 43(1): 88-92.
- Tseng CL, Greenberg JD, Helmer D, Rajan M, Tiwari A, Miller D, Crystal S, Hawley G, Pogach L. Dual-system utilization affects regional variation in prevention quality indicators: the case of amputations among veterans with diabetes. American Journal of Managed Care. 2004; 10(11 Pt 2): 886-92.
- Helmer DA, Tseng CL, Brimacombe M, Rajan M, Stiptzarov N, Pogach L. Applying diabetes-related Prevention Quality Indicators to a national cohort of veterans with diabetes. Diabetes Care. 2003; 26(11): 3017-23.
