Abstract P98: Change in Racial and Ethnic Disparities in Use of Inpatient Cardiovascular Surgeries in Postreform Massachusetts
Authors: Hanchate Amresh D , Lasser Karen , McCormick Danny , DAmore Meredith , Kressin Nancy 
Published: July 2021

BACKGROUND
The 2006 Massachusetts (MA) health reform increased insurance coverage to near-universal levels, but its impact on access to care is not known. We examined post-reform change in racial/ethnic differences in use of two cardiovascular procedures - percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass graft (CABG) - and two non-cardiovascular procedures (knee and hip replacements) documented to be underutilized by minorities.

METHODS
Using discharge data on all MA hospitalizations for 21 months preceding and following implementation of the reform, we identified all PTCA, CABG and joint (knee, hip) replacement procedures performed for patients aged >=40. Stratifying census population by race/ethnicity, we estimated pre- and post-reform population-based procedure rates, and their changes, for those aged 40-64, adjusting for secular changes unrelated to reform by capturing corresponding changes for those aged >= 65, whose coverage (Medicare) was unaffected by reform.

RESULTS
There was a secular decrease in use of PTCA and CABG for all groups (of 18% or more); use of joint replacement increased (>=20%). Post-reform, Black/White ratio of combined PTCA & CABG procedure rate improved from 0.77 to 0.82, with a smaller decrease for Blacks (18%) than Whites (24%). Difference in Hispanic/White PTCA & CABG procedure rate was not significant pre- and post-reform. Post-reform change associated with reform was not significant. Use of joint replacement increased for both minorities vs. Whites; change associated with reform was sizable for all groups (>=7%; significant for Whites only).

CONCLUSIONS
Use of inpatient PTCA and CABG shows a largely secular decrease, with little change associated with reform. While Black-White difference in PTCA and CABG rate decreased marginally, the rate among Blacks remained significantly lower than for Whites and Hispanics. Limitation: clinical appropriateness of the procedures could not be confirmed.

Table 1. Differences in Procedure Rates and Post-Reform Change in Massachusetts: Age 40-64

PTCA & CABG
Knee & Hip Replacement

Whites
Blacks
Hispanics
Whites
Blacks
Hispanics

Pre-reform Procedure Rate/10,000 pop.
c

38
29
38
30
31
13

Procedure Rate Ratio, Non-White/White (p-value for test of ratio=1)

0.77***
0.99

1.03
0.42***

Post-reform Procedure Rate/10,000 pop.
c

29
24
31
35
41
18

Procedure Rate Ratio, Non-White/White (p-value for test of ratio=1)

0.82***
1.04

1.18**
0.52***

Total Post-reform Change, %
d

-24%***
-18%***
-19%***
20%***
36%***
40%***

Difference, Non-White -White (p-value for test of difference=0)

5.2%
5.1%

16%*
20%**

Net Post-reform Change, %
e
(p-value for test of change=0)

-0.9%
-2.2%
2.9%
7%***
12%
18%

a) ***, ** and * denote p-value <=0.001, <=0.01 and <=0.05 respectively

b) Pre-reform period=(Oct 2004 to Jun 2006) and post-reform period=(Jan 2008 to Sept 2009) are 21 months each

c) Procedure rates, adjusted for sex and age differences, are estimated by direct standardization method

d) Total post-reform change in procedure rate is the simple % change in the pre-and post-reform procedure rates.

e) Net post-reform change is the estimate of change in procedure rate associated with the health reform. To separate the impact of health reform from secular temporal effects that may be unrelated to health reform, we used a difference-in-difference specification of a hierarchical Poisson regression model to estimate the net change among the 40-64 age group by contrasting the corresponding change for those among patients aged ≥65, assuming they had continuous Medicare coverage that was unaffected by the reform