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

Chuan-Fen Liu, MPH PhD

HERC Cyber Seminar

September 17, 2008 

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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

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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

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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

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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

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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

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

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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

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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

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Cohort Selection
| Exclusions                                | Count  |
|-------------------------------------------|--------|
| Initial Sample                            | 66,366 |
| Death prior or during FY 2000-2001        | 2,337  |
| Not Medicare eligible or Part A or B only | 36,050 |
| Enrolled in an HMO                        | 5,825  |
| Developed ESRD                            | 390    |
| No VA primary care in FY00                | 8,290  |
| Distance to VA facility unknown           | 250    |
| Working cohort                            | 14,753 |
| Age eligible                              | 12,295 |
| Disabled                                  | 2,458  |

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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

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Context of Reconciling Patient Data in Two Systems

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

Incentives & organizational structures differ in two systems

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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

Classification of VA and Medicare Outpatient Databy Care Type 

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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

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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

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Classification of CPT Codes
| General Category                              | CPT code range   |
|-----------------------------------------------|------------------|
| Anesthesia                                    | 00001 to 09999   |
| 99100 to 99150 *                              |
| Evaluation / Management (E&M)             | 99201 to 99499   |
| Medicine                                      | 90281 to 99602 * |
| Pathology/Laboratory                          | 80000 to 89999   |
| Psychiatry                                    | 90800 to 90900 * |
| Radiology                                     | 70000 to 79999   |
| Surgery                                       | 10000 to 69999   |
| * Some codes classified into other categories |

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

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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

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

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Hierarchical Algorithm

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Primary Care Type Classification between      		    Medicare and VA
| Classification Algorithm                  | Medicare(N = 739 K) | VA(N = 724 K)        |
|-------------------------------------------|---------------------|----------------------|
| Number of encounters                      | %                   | Number of encounters | % |
| VA-specific stop code                     | N/A                 | N/A                  | 199,438 | 27.5 |
| Primary care E/M codes                    | 249,280             | 33.7                 | 338,947 | 46.8 |
| Primary care provider type                | 197,274             | 20.8                 | 326,324 | 45.1 |
| Primary care type (E/M and provider type) | 103,032             | 13.9                 | 123,504 | 17.1 |

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Comparisons of Primary Care Use among VAMC and CBOC Patients

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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

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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

Preliminary Results

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Patient Characteristics

*p<0.05; ***p<0.001
| Baseline Characteristic (2000)                           | CBOC (n=8301) | VAMC (n=6452) |
|----------------------------------------------------------|---------------|---------------|
| Age (mean/SD)***                                         | 69.9 (9.1)    | 68.9 (9.9)    |
| Age < 45 (%)                                          | 2.4           | 2.2           |
| Age 45-54 (%)***                                         | 6.7           | 10.5          |
| Age 55-64 (%)                                            | 8.8           | 9.4           |
| Age 65+ (%)***                                           | 82.2          | 77.9          |
| Female (%)                                               | 2.7           | 2.8           |
| Race - White (%)***                                      | 90.6          | 86.5          |
| Married (%)*                                             | 67.8          | 64.7          |
| Percent Service Connected Disability (mean/SD)***        | 17.2 (27.1)   | 20.3 (30.5)   |
| Medicaid Enrollee (%)                                    | 5.2           | 5.8           |
| Free care - disability (%)                               | 38.3          | 40.5          |
| - low income (%)                                         | 42.7          | 44.3          |
| Distance to the closest VA (mi) (mean/SD)*               | 16.9 (18.2)   | 18.1 (17.2)   |
| DCG FY00 (including VA and Medicare Diagnoses) (mean/SD) | 0.96 (0.67)   | 0.99 (0.67)   |
| Per Capita Income in Zip Code (mean/SD)                  | 19570 (6117)  | 19463 (8877)  |
| % High School Graduates in Zip Code                      | 79.6 (10.1)   | 79.5 (11.3)   |
| Population per SQ. Mile in County (mean/SD)              | 861 (3320)    | 1018 (5517)   |

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VA and Medicare Primary Care Use
| 2001                          | 2002 | 2003 | 2004 |
|-------------------------------|------|------|------|
| CBOC                          | %    | %    | %    | % |
| Primary care in VA only       | 47.7 | 41.9 | 37.2 | 36.5 |
| Primary care in Medicare only | 10.9 | 14.5 | 18.6 | 18.2 |
| Dual use                      | 29.1 | 28.9 | 27.2 | 28.7 |
| No primary care use           | 12.3 | 14.3 | 17.0 | 16.6 |
| VAMC                          |
| Primary care in VA only       | 59.3 | 56.2 | 51.9 | 52.9 |
| Primary care in Medicare only | 5.8  | 7.9  | 10.3 | 9.5 |
| Dual use                      | 25.4 | 24.0 | 24.3 | 24.2 |
| No primary care use           | 9.6  | 12.0 | 13.6 | 13.4 |

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Unadjusted Primary Care Visits

***p<0.001
| YEAR | VA             | Medicare    | Total          |
|------|----------------|-------------|----------------|
| CBOC | VAMC           | CBOC        | VAMC           | CBOC | VAMC |
| 2001 | 2.38 (2.36)*** | 3.21 (3.59) | 1.47 (2.76)*** | 1.08 (2.60) | 3.84 (3.44)*** | 4.29 (4.25) |
| 2002 | 2.06 (2.21)*** | 3.05 (3.04) | 1.62(2.85)***  | 1.20(2.58) | 3.68 (3.41)*** | 4.26 (3.74) |
| 2003 | 1.80 (2.10)*** | 2.96 (2.87) | 1.84 (3.12)*** | 1.45 (2.79) | 3.63 (3.58)*** | 4.41 (3.80) |
| 2004 | 1.91 (2.28)*** | 3.11 (3.00) | 1.98 (3.32)*** | 1.30 (2.87) | 3.89 (3.80)*** | 3.42 (3.93) |

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Multivariate Results of Primary Care Use

Adjusted for patient characteristics

***p<0.001
| Coefficient                   |
|-------------------------------|
| VA                            | Medicare | Total |
| CBOC (reference group = VAMC) | -0.24*** | 0.13*** | -0.09*** |

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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

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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

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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.

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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