Do Physicians in Managed Care Networks
Respond to a Regulatory-Based Increase in
Clinical Autonomy?
The California Primary Treating Provider Experience
AcademyHealth Annual Research Meeting
June 26, 2005
Tricia Johnson
Rush University
Thanks to Alex Swedlow and the California Workers’ Compensation Institute for providing the
data and helpful comments and discussion throughout the project.
Background
Changes to the autonomy of the primary treating provider in California
have come almost full circle between 1993 and 2005
1993
Primary treating provider (PTP) presumed to be correct on
medical issues necessary to determine eligibility for
compensation
1996
Applied PTP presumption to all aspects of medical care and
rebuttable by preponderance of medical opinion (Minniear vs
Mt San Antonio Community College District)
20032004
Presumption granted to American Academy of Occupational
and Environmental Medicine (ACOEM) guidelines and only
contested with preponderance of “scientific medical” evidence
Workers’ Compensation Health Care in the
1990s
• Providers were required to
• Offer first dollar coverage with no copayments or
deductibles
• Cover all costs of care to treat the injury
• Allow workers to select their own providers after 1st 30
days
• California workers’ compensation managed care
networks
– Included both HMO and PPO-type products
Research Goals
• Examine whether managed care network and nonnetwork providers responded differently to the
regulatory-based increase in clinical autonomy
– Explore whether the managed care-based constraints on
utilization were binding
– Characterize the types of services most likely to be
affected by an increase in clinical autonomy
Methods
• Random sample of claims from the California
Workers’ Compensation Institute
• Dates of injury between January 1993 and
December 2000
• Closed claims with durations of medical treatment
through December 2001
• Permanent disability claims
• Back injuries only
Methods
• Independent variables:
– Legislative period (baseline, IRP, SRP)
– Network care (75% or more network care)
– Demographics, claim characteristics and job characteristics
• Three time periods, based on 1st date of medical
treatment
Baseline
1993 –1994
Initial Reform
1995 –1996
Full realization of 1993
reforms
Secondary Reform
1997 –2000
Full realization of appeals board
decision
Estimation Methods
• Service intensity
– Non-linear system of equations to test for structural
change in the quantities of services, using generalized
methods of moments
• Methods of treatment
– Multinomial regression model to test for structural change
Service Intensity Models
• Predict service utilization for ten key service groups:
–
–
–
–
Office visits
Surgery (with anesthesia)
Diagnostic radiology
Diagnostic testing – MRI,
CT scan
– Medical-legal
consultations
Physical medicine
– Physical medicine –
passive
– Physical medicine – active
– Chiropractic
– Other physical medicine
treatments
– Physical medicine
assessments
Methods of Treatment
SERVICE GROUPS
METHODS
O.V.
Diag Rad
None
Office visits only
Diag Test
PMR
Chiro
Surgery
All other combinations
YES
PMR w/o diag
MAYBE
Diag rad/US
MAYBE
Diag test (MRI, CT)
MAYBE
Manipulations
MAYBE
MAYBE
MAYBE
MAYBE
PMR w/diag
MAYBE
MAYBE
MAYBE
YES
Surgery
MAYBE
MAYBE
MAYBE
MAYBE
YES
YES
YES
YES
MAYBE
YES
Methods of Treatment Results
PM w/diag
Non-Network Claims
Base
SRP
%
%
%
Chg
0.30
0.16 -46%
Network Claims
Base
SRP
%
%
%
Chg
0.25
0.19 -26%
Manipulations
0.28
0.54
90%
0.23
0.47
105%
Diag rad
0.17
0.08
-53%
0.22
0.14
-38%
Surgery
0.03
0.05
72%
0.01
0.04
213%
All Other
0.25
0.18
-28%
0.29
0.16
-45%
Total
1.0
1.0
1.0
1.0
Method
NOTES: Changes significant at 0.05 or better
Service Intensity Results
Non-Network Claims
Network Claims
Base
Chg to
SRP
Pct
Chg
Base
Chg to
SRP
Pct
Chg
Office visits
6.7
-0.4
-6%
6.4
0.3
NS
Surgery
0.06
0.08
138%
0.02
0.07
318%
Diag rad
2.4
0.18
8%
2.0
0.12
NS
Diag testing
0.5
0.3
57%
0.3
0.2
47%
Service
NOTES: changes reported if significant at 0.05 or better; NS = insignificant
Service Intensity
Non-Network versus Network, PD Claims
Non-Network Claims
Network Claims
Pct
Chg
Base
Chg to
SRP
Pct
Chg
Service
Base
Chg to
SRP
PMR Assess
0.6
0.2
36%
0.4
0.3
71%
Passive PMR
17.7
13.6
77%
14.2
5.7
40%
Active PMR
6.5
4.2
65%
4.1
2.8
68%
Chiro
7.6
11.9
157%
6.7
5.6
83%
NOTES: changes reported if significant at 0.01 or better; NS = insignificant
Conclusions
• Utilization increased for both network and non-network
providers after the relaxation of regulatory constraints
– But managed care networks appeared to mitigate the
increases observed in non-network physicians – with no
demand-side cost sharing
– Treating non-network claims with SRP levels of network
care in the SRP would have saved $7.5M ($1374/PD
claim)
– Treating non-network claims with Baseline levels of
network care would have saved $11.5M ($2122/PD claim)
Conclusions
• Increase in the use of chiropractic care was
largest change in treating occupational back
injuries
– Non-network and network claims were approximately 25
percentage points more likely to receive chiropractic
treatment method
• Changes in the quantities of services were
pervasive
– Physical medicine procedures increased consistently
– Changes large in absolute and percentage terms
Limitations
• No information on changes in the managed care
networks’ utilization management procedures
during the time period
• No controls for different types of managed care
plans
• All back injuries – no controls for the types of back
injuries and crude measures of severity