Evaluating Quality and Value of US Ambulatory Care Delivered Among Medicaid Expansion/Non-Expansion States, 2012-2015

Evaluating the Quality and Value of U.S. Ambulatory Care Delivered Among Medicaid Expansion States and Non-Expansion States, 2012-2015

Quasi-experimental pre-post analysis of the rate of high-value and low-value care services between states that expanded Medicaid and states that did not expand Medicaid January 1, 2014, for adult ambulatory visits, using visit-level survey data from the National Ambulatory Medical Care Survey January 1, 2012 - December 31, 2015.

Study Overview

• Status: Active, not recruiting
• Conditions: Medicaid Expansion, High-value Care, Low-value Care
• Intervention / Treatment: Other: Medicaid Expansion

Detailed Description

Data Source: Visit level data obtained from the National Ambulatory Medical Care Survey (NAMCS) between January 1, 2012-December 31, 2015.

Identification of Observations (Visits) for Primary Analysis: Adult visits in states that did expand Medicaid January 1, 2014 (experimental group) and states that did not expand Medicaid January 1, 2014 (control group). Eight Medicaid expansion states (experimental group): Arizona, California, Illinois, Massachusetts, New Jersey, Ohio, Washington Five states that did not expand Medicaid (control group): Florida, Georgia, North Carolina, Texas, Virginia. Visits will be included only if they could receive a low value service (visits for back pain, headache, general medical exam, URI) or high value service (visits with patients who have CAD, DM, CVD, Depression, CHF, Osteoporosis and no exclusion to receive the indicated high value service) when evaluating low value service counts and high value service counts respectively as opposed to all adult visits regardless of the opportunity to receive a high value or low value care service (e.g. visit for hand pain and none of the high or low value areas above.)

Identification of Observations (Visits) for Secondary Analyses: Medicaid patient subpopulation will be defined as those visits for primary analysis that are coded with Medicaid as a pay type for the visit. "New" Medicaid patient subpopulation will be defined as those visits for primary analysis that are coded with Medicaid as a pay type, have not seen before, to a provider who is accepting new patients and accepts Medicaid for new patients.

Create Indicator Variables for Primary and Secondary Outcome Analyses: Develop a set of low value and high value services with distinct inclusion and exclusion criteria for each service. Create indicator variable for each high value and low value service. Low value care measures (Imaging for Low Back Pain, Opioid for Low Back Pain, Opioid for Headache, Imaging for Headache, Antibiotic for Upper Respiratory Infection, General Medical Examination with ECG ordered, General Medical Examination with Urinalysis ordered.) High value care measures (Antiplatelet for CAD, Beta Blocker for CAD, Statin for CAD, Anticoagulation for Atrial Fibrillation, Statin for DM, Antiplatelet CVD, Treatment for Depression, Beta Blocker for CHF, ACE/ARB/ARNI for CHF, Treatment for Osteoporosis)

Analysis: Evaluate for pre-intervention (Medicaid Expansion) parallel trends (This has already been established). Then perform pre-post difference-in-differences analyses of primary and secondary outcomes between the experimental group (states that expanded Medicaid) and control group (states that did not expand Medicaid). Regression analysis will be performed to adjust for respondent age, sex, race/ethnicity, number of chronic illnesses, and clinic rural/urban location. Stratified models based on payer type will allow for analyses of the Medicaid population. Perform sensitivity analyses of primary and secondary outcomes.

• Study Type: Observational
• Enrollment (Actual): 200000

Contacts and Locations

Study Locations

• United States
  • Michigan
    • Ann Arbor, Michigan, United States, 48109
      • The University of Michigan

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Probability Sample

Study Population

NAMCS Adult Visits between 01/01/2012 and 12/31/2015. The data source is a nationally representative probability sample of U.S. ambulatory care visits

Description

Inclusion Criteria: NAMCS Adult Visits between 01/01/2012 and 12/31/2015 Exclusion Criteria: <18 years old, visits before 01/01/2012, visits after 12/31/2015

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Retrospective

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Medicaid expansion states; Eight Medicaid expansion states: (experimental group): Arizona, California, Illinois, Massachusetts, New Jersey, Ohio, Washington	Other: Medicaid Expansion; Expansion of Medicaid, 01/01/2014
Non-Medicaid expansion states; Five states that did not expand Medicaid (control group): Florida, Georgia, North Carolina, Texas, Virginia

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Rate of low-value and high-value services for adult ambulatory visits.	Ex. Numerator = count of high value services provided for adult visits in Medicaid expansion states in 2012/ Denominator = Count of adult visits in Medicaid expansion state in 2012 that had the potential to receive a high value service.	pre (01/01/2012 - 12/31/2013) and post (01/01/2014 - 12/31/2015) Medicaid expansion

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Adult ambulatory visit volume changes	All adults, Medicaid adults, "New" Medicaid adults	pre (01/01/2012 - 12/31/2013) and post (01/01/2014 - 12/31/2015) Medicaid expansion
Rate of low-value and high-value services for Medicaid adult ambulatory visits	Ex. Numerator = count of high value services provided for Medicaid adult visits in Medicaid expansion states in 2012/ Denominator = Count of Medicaid adult visits in Medicaid expansion state in 2012 that had the potential to receive a high value service	pre (01/01/2012 - 12/31/2013) and post (01/01/2014 - 12/31/2015) Medicaid expansion
Rate of low-value and high-value services for "New" Medicaid adult ambulatory visits.	Ex. Numerator = count of high value services provided for "New" Medicaid adult visits in Medicaid expansion states in 2012/ Denominator = Count of "New" Medicaid adult visits in Medicaid expansion state in 2012 that had the potential to receive a high value service.	pre (01/01/2012 - 12/31/2013) and post (01/01/2014 - 12/31/2015) Medicaid expansion

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sensitivity analysis: repeat primary and secondary analysis with all adult visits, Medicaid visits, and "New" Medicaid visits	1. Repeat primary and secondary analysis with all adult visits, Medicaid visits and "New" Medicaid visits with a denominator of all visits (not the denominator of visits with potential to receive low or high value service as described for the primary analyses)	pre (01/01/2012 - 12/31/2013) and post (01/01/2014 - 12/31/2015) Medicaid expansion

Collaborators and Investigators

• Sponsor: University of California, Los Angeles
• Collaborators: University of Michigan

Study record dates

Study Major Dates

• Study Start (Actual): October 1, 2021
• Primary Completion (Anticipated): May 1, 2022
• Study Completion (Anticipated): May 1, 2022

Study Registration Dates

• First Submitted: March 31, 2022
• First Submitted That Met QC Criteria: March 31, 2022
• First Posted (Actual): April 8, 2022

Study Record Updates

• Last Update Posted (Actual): April 8, 2022
• Last Update Submitted That Met QC Criteria: March 31, 2022
• Last Verified: March 1, 2022

More Information

Terms related to this study

• Other Study ID Numbers: No unique protocol ID

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Yes
• IPD Plan Description: Publicly available NAMCS data

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No