Use of Primary Care in VA and Medicare among VAMC and CBOC Patients

1. Use of Primary Care in VA and Medicare among VAMC and CBOC Patients Chuan-Fen Liu, MPH PhD HERC Cyber Seminar September 17, 2008

2. Dual Use, Continuity of Care, and Duplication of Services in VA and Medicare • Funded by VA HSR&D, IIR 04-292 • Project team • Seattle: Chuan-Fen Liu, PhD; Michael Chapko, PhD; Chris Bryson, MD; Nancy Sharp, PhD; Mark Perkins, PharmD • Durham: Matt Maciejewski, PhD • Little Rock: John Fortney, PhD • Boston: Jim Burgess, PhD • University of Chicago: Will Manning, PhD

3. Outline • Background • Classification of primary care across VA and Medicare records • Goal: consistent classification of primary care • Preliminary results of comparisons of VAMC and CBOC patients in 2001 - 2004

4. Background • VA organizational reform • Veterans Eligibility Reform Act of 1996 • Moving from inpatient to primary care-oriented outpatient care • Establishment of Community Based Outpatient Clinics (CBOCs) in 1995 • Improve access to primary care • Contain cost of VA care

5. CBOCs • Congressional approval process • Services: primary care and mental health care (2001) • Two types: VA-staffed and contract • VA-staffed: VA providers or mixed; VA space • Contract: non-VA providers; non-VA space; capitated or fee basis • 718 CBOCs as of March 2008 • 162 contract and 556 VA-staffed CBOCs

6. Previous CBOC Evaluations • CBOC and VAMC comparisons • Comparable satisfaction and quality of care • CBOC patients – • More likely to be older, healthier, and new VA users • More primary care visits, but similar primary care costs • Lower odds of using specialty, mental health, ancillary and hospital services • Among users, fewer visits and lower costs in specialty, mental health, ancillary, and inpatient care • Lower total outpatient and total costs Chapko et al., Borowsky et al., Hedeen et al., Maciejewski et al., and Fortney et al., Medical Care 2002; Maciejewski et al., BMC HSR 2007

7. Issues with Previous Evaluations • Only examined VA experience • Were lower use and expenditure offset by higher non-VA use and expenditure?

8. Objective • Assess whether Medicare eligible veterans who get primary care at CBOCs have different primary care use than those who get primary care at VAMCs • Primary care use = VA or Medicare

9. Study Design • Retrospective cohort study • Study period: FY2000 – 2004 • Patient identification in FY2000 • Follow-up period: FY 2001 – FY 2004 • Study sample: • Medicare eligible VA primary care patients from the previous CBOC cost evaluation study • Random sample of primary care patients from 108 CBOCs and 72 VAMCs • Data sources: • Medicare claims • VA administrative datasets

10. Cohort Selection

11. Matching VA and Medicare Outpatient Services • Central challenge of identifying primary care in VA and Medicare • Data generating process • Clinical data vs. billing records • Financial incentives • Medicare doesn’t have stop codes • Goal: Classify VA and Medicare encounters as primary care or “other” in consistent way

12. VA providers Closed system Employed by VA Focus on treatment ICD-9 coding higher priority than CPT coding Providers code CPTs Clinic stops used to define outpatient care types Medicare providers Fee-for-service Individual practices Focus on billing payors CPT coding is priority Coders are instrumental UB-92 bill used to organize care Primary care not explicit Context of Reconciling Patient Data in Two Systems Incentives & organizational structures differ in two systems

13. Philosophies of Matching • Try to make VA look like Medicare • Use CPTs and match as though VA data are billing data (severely undercounts VA work) • Try to make Medicare look like VA • Classify Medicare claims into “Clinic Stops” • Create a hybrid and transform both • Pick and choose from data advantages and disadvantages in each sector

14. Classification of VA and Medicare Outpatient Databy Care Type

15. General Approach • Classify VA and Medicare outpatient encounters into “Care Type” using variables common to both systems • Primary Care • Specialty • Mental Health • Diagnostic • Combination of provider specialty and procedure (CPT-4) codes • Goal: Identify primary care with face validity and consistency

16. Provider Specialty Types • Primary care: • Physicians: family practice; internal medicine • Nurse practitioners: family practice; primary care; women’s health • Specialty care • Mental health • Diagnostic care

17. Classification of CPT Codes

18. E&M Codes • Specialty care E&M codes • Performed by specialists • Performed in acute care and hospital settings • Primary Care E&M codes

19. Data Management • Outpatient encounter definition • Same patient, same date and same provider specialty • Omitted records for selected provider specialties • Podiatrists, dentists, etc. • Medicare claims • Need to convert Medicare claims into encounters • VA records: face-to-face encounters • Exclude phone stops or stops without provider contacts • Provider specialty • Medicare – one per record • VA – up to 3 per record • Use the first physician or nurse practitioner specialty code • Eliminate nurse, PA, intern, resident, nutritionist, or pharmacist as a provider

20. General Principles • If specialty provider, encounter cannot be primary care • If specialty E/M procedure or “Medicine procedure” encounter cannot be primary care

21. Hierarchical Algorithm

22. Primary Care Type Classification between Medicare and VA

23. Comparisons of Primary Care Use among VAMC and CBOC Patients

24. Variable Definitions • VAMC/CBOC primary care user defined based on the majority of primary care visits in each year • Primary care user status in each year: • Dual users: at least one primary care visit in VA and one in Medicare • VA-only • Medicare only • Non-user • Number of VA, Medicare and total primary care visits in 2001 – 2004

25. Data Analysis • Generalized estimating equation (GEE) model with negative binomial distribution and log link with exchangeble correlation • Adjusted for sampling weights from the original CBOC study

26. Preliminary Results

27. Patient Characteristics *p<0.05; ***p<0.001

28. VA and Medicare Primary Care Use

29. Unadjusted Primary Care Visits ***p<0.001

30. Multivariate Results of Primary Care Use Adjusted for patient characteristics ***p<0.001

31. Summary • CBOC patients were more likely than VAMC patients to use primary care services in Medicare • Similar time trends between CBOC and VAMC patients • The proportion of VA only primary care users decreased • Dual use stayed stable • Medicare only increased over time • Compared to VAMC patients, CBOC patients had • Fewer VA primary care visits • More Medicare primary care visits • Fewer total primary care visits, including both VA and Medicare

32. Limitations • Not a random sample of VA primary care users: original sample is primary care users in large CBOCs & VAMCs in 2000 • Imperfect classification of primary care visits across VA and Medicare systems with hybrid algorithm • No Medicaid data on non-elderly Medicare-eligible vets

33. Conclusions • Among Medicare eligible veterans: • CBOC patients use less VA primary care than VAMC patients • CBOC patients use more Medicare primary care • Difference between CBOC and VAMC patients in total primary care use decreases when Medicare use is included • Continuity of care, chronic disease management and performance assessment may be impacted by dual use of VA and Medicare primary care services, particularly for CBOC users.

34. Highlights of the Project • Determinants of primary care reliance in VA • Comparisons of continuity of primary care among VA-only primary care users, Medicare only primary care users and dual users • Duplication of services among dual users