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 Carecmah@fas.harvard.edu

AcknowledgementsCo-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

BackgroundDisparities 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 PolicyObjective

To reduce cost as a barrierTo 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 QuestionsDoes 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 self-monitoring for black and white diabetes patients?

PurposeTo 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 & SettingResearch Design

Longitudinal, retrospective cohort analysis

Study Setting Harvard Vanguard Medical Associates (HVMA)Harvard Pilgrim Health Care (HPHC)

HPHC Coverage PolicyStart 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)

Ambulatory Medical Records

Membership/ Enrollment

Pharmacy Claims

Clinical Encounters

HbA1c Lab Results

Race Identification

Drug Therapy

Dispensed Test Strips

Demographic Info Home Address (linked by census

block group)

Days Enrolled

PATIENT STUDY ID

Census File

Key MeasuresMain independent measure

RaceRace (black v. white)Outcome measures

Incidence of SMBGIncidence of SMBG (≥1 strip) Discontinuation of SMBGDiscontinuation of SMBG (>180 days w/out strips)

Covariates FixedFixed (age, sex, census-derived median HH income &

educational level, drug type, BMI, HbA1c test, primary health site)

Time-VaryingTime-Varying (mean HbA1c values in prior month, # MD visits per month)

Main Analytical MethodsKaplan-Meier & Log-Rank Tests

Cumulative rates of initiation of SMBGCumulative rates of discontinuation of SMBG

Extended Segmented Cox ModelsAdjusting for patient-level fixed & time-varying

covariatesRelative (hazard) rates of initiation of SMBG

(blacks relative to whites)

Pre-Policy Patient DifferencesAny

InsulinOral Sulfonylurea

Only

Black

(n=264)

White

(n=613)

Black

(n=250)

White

(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 Insulin Treatment (N=567)

0

0.2

0.4

0.6

0.8

1

Ap

r-92

Au

g-9

2

De

c-9

2

Ap

r-93

Au

g-9

3

De

c-9

3

Ap

r-94

Au

g-9

4

De

c-9

4

Ap

r-95

Any Pre-Policy Oral Treatment (N=904)

0

0.2

0.4

0.6

0.8

1

Ap

r-92

Au

g-9

2

De

c-9

2

Ap

r-93

Au

g-9

3

De

c-9

3

Ap

r-94

Au

g-9

4

De

c-9

4

Ap

r-95

Black White

% w

ith

SM

BG phase-inphase-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

Censoring at first insulin use or never initiated SMBG

* p <0.05

Controlling for age, glycemic control, time-dependent drug use, and time-dependent number of physician visits

Discontinuation of SMBG

0102030405060708090

100

6 Months 12 Months 18 Months

Months since SMBG Initiation

% S

MB

G D

isco

nti

nu

atio

n

Black (n=59)

White (n=134)

p<0.05

Post-Policy SMBG Initiators

Discontinuation = >180 days without test strip use

SummaryTrials 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

LimitationsMissing race data

Important unmeasured factorsSocio-cultural factors (attitudes, perceptions,

cultural beliefs/values)Duration of illnessIntensity of medication use

Single HMO

Take Home PointsCoverage 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