1. Neel Gandhi, MD VACS Leadership Meeting November 5, 2003
Trends in Healthcare Utilization among HIV positive Veterans from : The VACS Virtual Cohort Data
Neel Gandhi, MD
VACS Leadership Meeting
November 5, 2003

2. Introduction
Throughout the 1990s, emphasis on shifting healthcare utilization from inpatient to outpatient setting
Utilization at VA hospitals:
Mean number of hospital days per patient-year declined by 40-60% from 1994 to 1998
Demonstrated among chronic medical and psychiatric illnesses (Ashton et al NEJM 2003)
Good Afternoon.
Throughout the 1990s, emphasis was placed on shifting healthcare utilization from the inpatient setting to the outpatient setting.
Recent evidence demonstrates that this was true in the VA system as well. The mean number of hospital days per patient-year declined by 40 to 60% from years 1994 to This decline was demonstrated nationwide among patients with chronic medical or psychiatric illnesses

3. Utilization by HIV patients
Decline in inpatient utilization well documented from 1996 to 1998
Attributed to introduction of Highly Active Antiretroviral Therapy (HAART)
Unclear if this decline influenced by shift away from inpatient utilization in 1990s
Few reports available regarding utilization among HIV patients after 1998
A decline in inpatient utilization has also been documented among HIV patients from 1996 to 1998.
This decline is usually attributed to the introduction of Highly Active Antiretroviral Therapy. It is unclear, however, if this decline was also influenced by the shift away from inpatient utilization seen in other medical illnesses in 1990s
Additionally, few reports are available in the literature describing utilization among HIV patients after 1998.

4. Objectives
Among HIV-positive and HIV-negative patients at VA Medical Centers from 1998 to 2002, to examine:
Trends in inpatient and outpatient healthcare utilization following initial presentation
The effect of calendar year of presentation on patterns of utilization
With this background, we proposed a study to examine, among HIV-positive and HIV-negative patients at VA medical Centers from 1998 to 2002, to examine:
The trends of inpatient and outpatient healthcare utilization following initial presentation.
And the effect of calendar year of presentation on patterns of utilization

5. Hypotheses
Inpatient utilization would be greatest in year of presentation and gradually decline thereafter
Outpatient utilization would increase to offset diminished inpatient utilization
Changes in utilization among HIV group would not be subject to variation seen in non-HIV patients
Our hypotheses when initiating this study, were that inpatient utilization would be greatest in the year of presentation and then gradually decline thereafter.
Outpatient utilization, we expected, would increase to offset the diminished inpatient utilization
Additionally, we believed that the changes in utilization seen among the HIV group, would not be subject to the variation seen historically in non-HIV patients

6. Methods Retrospective observational study
Examining patterns of inpatient and outpatient utilization among HIV-positive patients and HIV-negative controls from fiscal years (FY) 1998 to 2002
Data abstracted from VA Austin Automation Center, uploaded from all 176 VA Medical Centers in US
This is a retrospective observational study, examining the patterns of inpatient and outpatient utilization among HIV-positive patients and HIV-negative controls from fiscal years 1998 to 2002.
The data were abstracted from the VA Austin Automation Center, which contains information uploaded from all 176 VA Medical Centers in the US.

7. Study Sample HIV patients Control patients
Using ICD-9 and DRG codes, HIV patients identified in Austin database from FY 1991 to 2002 (N = 42,586)
Eligible for study if first HIV code in FY 1998 to 2001
(N = 15,094)
Control patients
Lack an HIV-related ICD-9 or DRG code
Matched 1:1 with HIV patients on age, sex, race and VISN
Required to have active utilization in year that HIV match first identified with HIV code
Using ICD-9 and DRG codes, 42-thousand-5-hundred-86 HIV patients have been identified in the Austin database from 1991 to 2002.
These patients were eligible for our study if their first HIV code occurred between fiscal years 1998 and 2001.
Control patients were drawn from the pool of patients who lacked an HIV-related ICD-9 or DRG code. Controls were matched on a one-to-one basis with HIV patients for age, sex, race and VISN. Control patients were required to have active utilization in the same fiscal year that their HIV match was first identified with an HIV diagnostic code

8. Definitions Utilization Year of presentation
Inpatient: mean number of hospital days and admissions per patient-year
Outpatient: mean number of outpatient visits to any VA clinic per patient-year
Year of presentation
HIV patients: Fiscal year in which patient is first identified as having HIV-related code
Control patients: assigned year of presentation of HIV match
Before I move on, I would like to mentioned a few definitions we used for this study:
We defined utilization in the inpatient setting to be the mean number of hospital days and mean number of hospital admissions per patient year. Outpatient utilization was defined as the mean number of outpatient visits to any VA clinic per patient year.
Another important definition to mention is Year of Presentation. We used the term “year of presentation” to refer to the fiscal year in which HIV patients were first identified with an HIV diagnostic code. Control patients were assigned the year of presentation of their HIV match.

9. Analysis Patients were grouped by HIV status and year of presentation
Utilization data were aggregated based on the fiscal year in which they occurred
Mean utilization per patient-year in year of presentation was compared to subsequent follow-up years
For our analyses, patients were grouped based on HIV status and year of presentation.
The utilization data were aggregated based on the fiscal year in which it occurred.
Mean utilization per patient-year in the year of presentation was compared to utilization in subsequent follow-up years.

10. Outcomes
Change in inpatient and outpatient utilization per patient-year as compared to baseline year of presentation
Variation in mean utilization between groups with differing years of presentation
The outcomes we were interested in, were the change in inpatient and outpatient utilization per patient-year, as compared to the baseline year of presentation.
We were also interested the variation in mean utilization values seen between cohorts of differing calendar years of presentation.

11. Results: Demographics
Demographics (Matched)
HIV Group
Control Group
Age: Mean years (SD)
49.2 (12.6)
Range
18 – 99
Sex: Male (%)
14,642 (97)
14,641 (97)
Race: n (%)
White
5436 (36.0)
Black
5841 (38.7)
Hispanic
1011 (6.7)
Native American
31 (0.21)
Asian
60 (0.40)
Unknown
2716 (18.0)
The results presented here are for baseline demographics of the study patients. Please remember that we matched patients in a 1-to-1 manner for these demographics. As expected the values in the two groups are nearly identical.
The mean age of each group was 49.2 years with a standard deviation of 12.6 years. The groups were 97% male. The racial breakdown was 36% white, 39% black and 7% Hispanic. Less than 1% of each group was Native American or Asian. [Racial demographics were not known for 18% of the patients.]

12. Results: Year of Presentation
Year of Presentation (Matched)
HIV Group
n (%)
Control Group
1998
4781 (31.7)
1999
3996 (26.5)
2000
3394 (22.5)
2001
2924 (19.4)
Total
15,094 (100)
In this slide, we present a breakdown of the study groups based on the year in which patients presented with an HIV-related diagnostic code. Again, please recall that controls were matched to have utilization in that same year.
32% of patients presented in 1998, 27% 1999, 23% in 2000 and 19 % in 2001.

13. Prior Utilization Utilization prior to Year of Presentation HIV Group
Control Group
Year prior: n (%)
8,511 (54.6)
11,313 (74.9)
Ever: n (%)
11,194 (74.2)
13,087 (86.8)
# Years: Mean (SD)
4.3 (3.5)
5.1 (3.2)
Before I present the outcomes of this study, I wanted to share a finding that surprised us.
In this slide, I present data regarding utilization within the VA system prior to first appearance of an HIV diagnostic code.
We found that roughly 55% of patients in the HIV group had utilization in the VA, the year prior to presenting with an HIV diagnostic code. In fact, 74% of HIV patients were seen in the VA at one time or another, prior to presenting with an HIV diagnostic code. The mean number of years between HIV patients’ first utilization in the VA system and their first HIV code was 4.3 years.
These prior utilization numbers are comparable, although somewhat smaller than those seen with the control group.

14. Inpatient Utilization: Hospital Days
With this slide, I begin my presentation of utilization data from this study. I will be presenting a series of graphs which will be similar in their make up. The data plotted will be for 4 groups based on the patients year of presentation. The y-axis will represent the mean utilization which we are analyzing; and the x-axis represents years of follow-up after presentation. The first graph of each pair will be for the HIV group and the second will present data from the control group.
This slide shows Inpatient utilization as measured by mean # of hospital days per patient year. With these data we see that utilization is greatest in the year of presentation. It declines sharply in the second year and then more gradually in the remaining years of follow-up.
Although utilization varies as patients progress in their course of follow-up, we note that the year in which they presented has little effect on their levels of utilization. [The lines for the individual cohorts overlap completely.]

15. Inpatient Utilization: Hospital Days
This slide presents the same analysis, but for the Control Group.
Here we note that inpatient utilization has a stable to slightly declining trend over the course of follow-up.
In contrast to the HIV group, however, significant differences in utilization are present, based on year of presentation. It appears that the latter years of presentation have significantly lower rates of hospital days than the earlier years of presentation.
Analyses were also performed for number of hospital admissions and ER visits per patient year. The utilization patterns mirrored those seen in these two graphs, and thus will not be shown.

16. Stratified Analysis for Prior Utilization
In an effort to better understand the pattern of inpatient utilization just seen, we performed a stratified analysis for utilization in the year prior to presentation. Our goal was to determine whether differences in prior utilization were responsible for the large number of hospital days seen in the first year of the HIV group as compared to subsequent years.
Here we find that regardless of whether the patients had utilization in the year prior to presentation, the utilization in the first year remains twice as great as that in subsequent years. Also noteworthy is that contrary to our initial belief, the patients who newly presented to the VA, had lesser utilization in the first year and for every year thereafter.

17. Stratified Analysis for Prior Utilization
In the same stratified analysis of the Control group, the trend of utilization is similar to the non-stratified analysis. Again, patients with no prior utilization had fewer hospital days initially and throughout follow-up.

18. Outpatient Utilization: All Visits
We now move onto Outpatient utilization. We analyzed all outpatient visits to VA clinics. In the HIV group, we find that the mean number of outpt visits declines gradually over the follow-up course, rather than increasing to compensate for the diminished inpatient utilization.
Again, please note here that there is minimal variation based on year of presentation.

19. Outpatient Utilization: All Visits
The outpatient utilization among the controls does increase, although gradually and only slightly.
Here the variation based on year of presentation also appears to be minimal.

20. Limitations of Virtual Cohort
These analyses are limited by absence of:
CD4 counts and Viral Loads
Date of HIV diagnosis
Data regarding HAART use
Addition of these data would allow further specificity of patterns of utilization among different clinical subgroups
Our analyses are limited by the absence of CD4 counts and viral loads, the actual date of HIV diagnosis and data regarding HAART use
The addition of these data would allow further specificity of patterns of utilization among different clinical subgroups

21. Conclusions
Healthcare utilization among HIV veterans greatest in year of presentation
Inpatient utilization two-fold greater in year of presentation compared to subsequent years
Outpatient utilization diminishes modestly, rather than increasing to offset declines in inpatient utilization
HIV utilization does not change significantly based on the year of presentation from 1998 to 2001
Differs from trend seen in non-HIV controls where inpatient utilization declined with each subsequent year of calendar time
From this study, we conclude:
First, Healthcare utilization among HIV veterans is greatest in year of presentation
Inpatient utilization is two-fold greater in the year of presentation as compared to subsequent years
Outpatient utilization diminishes modestly, rather than rising to offset declines in inpatient utilization
HIV utilization does not change significantly based on the year of presentation
This differs from trend seen in non-HIV controls where inpatient utilization declined with each subsequent year of calendar time

22. Conclusions cont’d
Stratified Analyses based on utilization in the year prior to presentation reveal:
Greater inpatient utilization in first year not influenced by prior utilization
Patients new to VA have less inpatient utilization in first year, which persists throughout the course of follow-up
Additionally, Stratified Analyses based on utilization in the year prior to presentation reveal:
The pattern of greater inpatient utilization in the first year is not influenced by whether the patient had utilization prior to presentation.
Patients new to the VA, however, have less utilization in the first year, which persists throughout the follow-up course.

23. Implications
Year of presentation it may provide an opportunity for optimization of care
Examination of practices in first year of HIV care (ie. coordination of care, patient education, screening and prophylaxis etc.) may reveal opportunities for improvement
Characterization of patients with prior utilization to identify “at risk” population who may benefit from earlier diagnosis and intervention
Further work necessary to determine why inpatient utilization lower among patients new to VA
There are several implications of our study:
First, since utilization is greatest in year of presentation, it may provide a good opportunity for optimization of care. Examination of practices in first year of HIV care (ie. coordination of care, patient education, screening and prophylaxis etc.) may reveal opportunities for improvement of care
Second, considering that the majority of HIV patients had prior utilization, characterization of these patients may identify an at risk population of veterans who may benefit from earlier diagnosis and intervention.
Third, further work is necessary to determine why inpatient utilization is lower for patients new to VA throughout their follow-up course.

25. Additional Slides

26. Number of Admissions

27. Number of Admissions cont’d

28. Urgent & Emergency Visits
Here we present Urgent and emergency visits. The utilization pattern here is similar to the inpatient utilization.

29. Urgent & Emergency Visits cont’d
It is true for the control group as well.

30. Medicine Clinic Visits

31. Medicine Clinic Visits cont’d

32. Baseline Marital Status
HIV Group
n (%)
Control Group
Married
3520 (23.3)
6638 (44.0)
Never Married
5935 (39.3)
3731 (24.7)
Divorced
4027 (26.7)
3458 (22.9)
Separated
342 (2.27)
70 (0.46)
Widowed
563 (3.73)
376 (2.49)
Unknown
701 (4.65)
818 (5.42)