Racial Differences in the
Impact of HMO Coverage of
Diabetes Blood Glucose
Monitors on Self-Monitoring
Connie A. Mah, M.S.
Department of Ambulatory Care & Prevention
Harvard Medical School & Harvard Pilgrim Health Care
cmah@fas.harvard.edu
Acknowledgements
 Co-Authors:
 Stephen B. Soumerai, ScD
 Alyce S. Adams, PhD
 Dennis Ross-Degnan, ScD
 Funders:
 AHRQ
 Harvard Pilgrim Health Care Foundation
 Consultants:
 Fang Zhang, PhD
 John D. Piette, PhD
 James Meigs, MD, MPH
Background
 Disparities in diabetes health & health
care use


Blacks have worse glycemic control
Blacks at greater risk of adverse outcomes
 Differences in diabetes quality of care
& self-management


Blacks receive lower quality of care
Blacks face greater barriers to self-management
Coverage Policy
 Objective
 To reduce cost as a barrier
 To increase access to high quality care
 Mandated in over 38 states
 Provision of glucose monitoring devices &
supplies
 Findings from parent evaluation study*
 Increased rates of SMBG
*Soumerai, Mah, Zhang, et al., Archives of Internal Medicine 2004 (164(6):645-52)
Key Research Questions
 Does this policy have the potential to
narrow some of the racial disparity in
diabetes self-management?
 Does providing free home glucose
monitors have differential impacts on selfmonitoring for black and white diabetes
patients?
Purpose
 To determine whether policy increased
initial trials of self-monitoring among black
versus white patients
 To investigate whether patients who
initiated self-monitoring after the policy
continued to self-monitor thereafter
Research Design & Setting
 Research Design

Longitudinal, retrospective cohort analysis
 Study Setting
Harvard Vanguard Medical Associates (HVMA)
 Harvard Pilgrim Health Care (HPHC)

HPHC Coverage Policy
 Start of Implementation: Oct 1,1993
 Objective
 To motivate diabetes patients to start monitoring their
blood glucose
 Policy Benefits
 Provision of glucose monitoring devices
 Self-management training & education
 Lower copay for up to 3 months’ supply of test strips
(≤$5/script)
Study Cohort
 Definition of Diabetes:
≥ 1 hospital discharge Dx; or
 ≥ 2 outpatient Dx; or
 ≥ 1 insulin or oral sulfonylurea Rx

 Black or White race only
 Continuous enrollment (1992-1996)
 N=2,275 adult patients
HVMA Data Sources (1992-1996)
Race
Identification
Clinical
Encounters
HbA1c Lab
Results
Ambulatory
Medical Records
PATIENT
STUDY ID
Pharmacy
Claims
Membership/
Enrollment
Demographic
Info
Days Enrolled
Dispensed
Test Strips
Drug
Therapy
Census File
Home Address
(linked by census
block group)
Key Measures
 Main independent measure
 Race (black v. white)
 Outcome measures
 Incidence of SMBG (≥1 strip)
 Discontinuation of SMBG (>180 days w/out strips)
 Covariates
 Fixed (age, sex, census-derived median HH income &
educational level, drug type, BMI, HbA1c test, primary
health site)
 Time-Varying (mean HbA1c values in prior month, #
MD visits per month)
Main Analytical Methods
 Kaplan-Meier & Log-Rank Tests
Cumulative rates of initiation of SMBG
 Cumulative rates of discontinuation of SMBG

 Extended Segmented Cox Models
Adjusting for patient-level fixed & time-varying
covariates
 Relative (hazard) rates of initiation of SMBG
(blacks relative to whites)

Pre-Policy Patient Differences
Any
Insulin
Black
White
(n=264) (n=613)
Oral Sulfonylurea
Only
Black
White
(n=250) (n=739)
Female
63.3%
50.4%
57.6%
44.0%
Mean Age
52±12
52±14
53±11
60±11
Mean BMI
32.7±7.1 30.5±7.5 32.0±6.3 32.1±7.2
Mean HbA1c
9.5±1.7
9.0±1.4
9.1±1.9
8.1±1.4
% Any SMBG
64.8%
77.8%
34.0%
30.8%
Bold denote p<0.05
Initiation of SMBG
Any Pre-Policy Oral
Treatment (N=904)
Any Pre-Policy Insulin
Treatment (N=567)
% with SMBG
1
0.8
1
phase-in
0.8
0.6
0.6
0.4
0.4
0.2
0.2
0
0
Apr-95
Dec-94
Aug-94
Apr-94
Dec-93
White
Aug-93
Apr-93
Dec-92
Aug-92
Apr-92
Apr-95
Dec-94
Aug-94
Apr-94
Dec-93
Aug-93
Apr-93
Dec-92
Aug-92
Apr-92
Black
phase-in
Est. Haz Ratio
95% CI
Pre-Policy Difference
(Black vs. White)
1.09
0.84,1.40
Post-Policy Difference
(Black vs. White)
1.35*
1.05,1.72
Controlling for age, glycemic control, time-dependent drug use, and timedependent number of physician visits
Censoring at first insulin use or never initiated SMBG
* p <0.05
Discontinuation of
SMBG
% SMBG Discontinuation
Post-Policy SMBG Initiators
100
90
80
70
60
50
40
30
20
10
0
Black (n=59)
White (n=134)
6 Months
12 Months
18 Months
Months since SMBG Initiation
p<0.05
Discontinuation = >180 days without test strip use
Summary
 Trials of self-monitoring in post-policy
 increase in SMBG
 greater for blacks on oral therapy
 Persistence after initiation of SMBG in
post-policy
 short-lived
Limitations
 Missing race data
 Important unmeasured factors
Socio-cultural factors (attitudes, perceptions,
cultural beliefs/values)
 Duration of illness
 Intensity of medication use

 Single HMO
Take Home Points
 Coverage is effective in engaging patients
in SMBG particularly blacks
 Sustainability must be addressed
 Additional interventions may be necessary
to improve long-term adherence and
clinical outcomes