Factors Influencing Primary Care Providers’ Decisions to Accept New Medicaid Patients Under Michigan’s Medicaid Expansion

ABSTRACT

Objectives: Michigan expanded Medicaid under the Affordable Care Act (ACA) through a federal waiver that permitted state-mandated features, including an emphasis on primary care. We investigated the factors associated with Michigan primary care providers (PCPs)’ decision to accept new Medicaid patients under Medicaid expansion.

Study Design: Statewide survey of PCPs informed by semistructured interviews.

Methods: After Michigan expanded Medicaid on April 1, 2014, we surveyed 2104 PCPs (including physician and nonphysician providers, such as nurse practitioners and physician assistants) with 12 or more assigned Medicaid expansion enrollees (response rate, 56%). To guide survey development and interpretation, we interviewed a separate group of 19 PCPs with Medicaid expansion enrollees from diverse urban and rural regions. Survey questions assessed PCPs’ current acceptance of new Medicaid patients.

Results: Of the 2104 surveyed PCPs, 78% reported that they were currently accepting additional Medicaid patients; 58% reported having at least some influence on the decision. Factors considered very/moderately important to the Medicaid acceptance decision included practice capacity to accept any new patients (69%), availability of specialists for Medicaid patients (56%), reimbursement amount (56%), psychosocial needs of Medicaid patients (50%), and illness burden of Medicaid patients (46%). PCPs accepting new Medicaid patients tended to be female, minorities, nonphysician providers, specialized in internal medicine, paid by salary, or working in practices with Medicaid-predominant payer mixes.

Conclusions: In the era after Medicaid expansion, PCPs placed importance on practice capacity, specialist availability, and patients’ medical and psychosocial needs when deciding whether to accept new Medicaid patients. To maintain primary care access for low-income patients with Medicaid, future efforts should focus on enhancing the diversity of the PCP workforce, encouraging healthcare professional training in underserved settings, and promoting practice-level innovations in scheduling and integration of specialist care.

Am J Manag Care. 2019;25(3):120-127Takeaway Points

In the era after Medicaid expansion, the factors considered important to Michigan primary care providers (PCPs) when deciding whether to accept additional Medicaid patients included the capacity to accept any new patients (69%), availability of specialists for Medicaid patients (56%), reimbursement amount (56%), psychosocial needs of Medicaid patients (50%), and illness burden of Medicaid patients (46%).

• PCPs continuing to accept new Medicaid patients tended to be female, minorities, nonphysician providers, specialized in internal medicine, paid by salary, or working in practices with Medicaid-predominant payer mixes.
• Policy makers should consider these factors in addition to reimbursement policies to ensure adequate PCP capacity in states with expanded Medicaid coverage.

As state and federal governments debate the future of the Affordable Care Act (ACA) and its Medicaid expansion, it seems likely that expanded Medicaid coverage will remain, but it will likely be modified by greater state flexibility in coverage and implementation.¹ The impact of expanded Medicaid in any form depends on several factors, including, crucially, the acceptance of Medicaid by healthcare providers and systems.

Payment has long been emphasized as a driver of physician participation in Medicaid. Prior studies have found that reimbursement level is important to healthcare providers’ decisions to accept Medicaid.^2-5 However, it is also important to carefully consider both the financial and nonfinancial factors that may influence providers’ participation in Medicaid and other programs.⁶

Since the 1980s, research has examined several nonfinancial factors associated with physician Medicaid acceptance, including characteristics of “high-share” Medicaid providers, such as younger age, female gender, and nonwhite race.^4,5,7-10 However, few studies have comprehensively examined which provider characteristics and practice settings may be associated with provider willingness to accept new Medicaid patients after the 1990s, when this was last examined in depth following the rapid growth of managed care. Given that influences on healthcare providers’ willingness to see Medicaid patients may have changed in the era after ACA Medicaid expansion, this question is worth revisiting.

Because primary care providers (PCPs) deliver frontline access to care for patients, understanding the factors associated with an adequate supply of PCPs who accept Medicaid patients is critically important. Access to care for Medicaid patients depends on several dimensions, including (1) providers’ willingness to accept any Medicaid patients, (2) the geographic distribution of available providers in relation to patients’ location, and (3) providers’ capacity and willingness to accept a greater number of Medicaid patients as demand rises (eg, after insurance coverage expansion). In the setting of Michigan’s Healthy Michigan Plan (HMP)—which expanded Medicaid under the ACA through a federal section 1115 waiver that permitted state-mandated features, including an emphasis on primary care¹¹—prior studies have examined the first 2 dimensions of provider Medicaid acceptance. With regard to whether primary care practices accepted any Medicaid patients, these studies demonstrated increased availability of PCP practices offering appointments to HMP patients after Medicaid expansion^12,13 despite rapid enrollment in the program,¹⁴ which was consistent with trends observed in 10 other states.^15,16 Regarding provider distribution, these increases in appointment availability appeared to be geographically concentrated in regions with lower pre-expansion Medicaid acceptance.¹⁷

The current study examines the third dimension of providers’ capacity and willingness to accept a greater number of Medicaid patients: whether PCPs who already have some Medicaid patients are willing to accept more in response to patient demand. In a recent study, Neprash and colleagues found that most physicians maintained or slightly increased their Medicaid participation rates after ACA Medicaid expansion, with greater increases observed in expansion states.¹⁸ Of note, approximately 20% of PCPs accounted for the care of 60% of Medicaid patients in that study. In other words, most increases in PCP Medicaid participation occurred among providers already caring for Medicaid patients. The authors of that study concluded that policy efforts to increase access to primary care should target existing Medicaid providers. Thus, focusing on PCPs already caring for Medicaid patients, we investigated what factors were associated with their continued acceptance of new Medicaid patients.

METHODS

Study Design

As part of a formal evaluation under contract with the Michigan Department of Health and Human Services (MDHHS) and required by CMS for a section 1115 waiver, we conducted a statewide survey of PCPs regarding their experiences with HMP enrollees, new practice approaches and innovations adopted or planned in response to HMP, and future plans regarding acceptance and care of HMP patients.¹⁹ As an evaluation of a public program, the University of Michigan and MDHHS institutional review boards deemed the study exempt.

Survey Sampling

The PCP sample was drawn from the MDHHS Data Warehouse, which stores data generated from encounters on all Medicaid and HMP enrollees and their providers, including provider demographics, specialty (assessed by linking National Provider Identifier [NPI] numbers from the Data Warehouse to each respondent’s National Plan and Provider Enumeration System profile), practice setting, and health plan participation. From the Warehouse, 7360 NPI numbers were identified as the assigned PCP for at least 1 HMP managed care enrollee (adult Medicaid expansion group) in April 2015, 1 year after the HMP launch. Nurse practitioners (NPs) and physician assistants (PAs) who were listed as the assigned PCP were also included in the sample. We considered PCPs with at least 12 assigned members (an average of 1 HMP enrollee per month) eligible for the survey in order to assess the perspectives of PCPs who had sufficient experience with HMP patients to provide informed input on the primary care—oriented features of the program for another related study.¹⁹ Thus, 2813 PCPs with fewer than 12 assigned members were excluded. Of the remaining 4547 PCPs, exclusions included 25 with an NPI entity code that did not reflect an individual provider (20 organizational NPIs, 4 deactivated, and 1 invalid), 161 with only pediatric specialty, 4 University of Michigan physicians involved in the HMP evaluation, and 35 with out-of-state addresses greater than 30 miles from the Michigan border. After exclusions, 4322 PCPs (3686 physicians and 636 NPs or PAs) remained in the survey sample.

Although we focused on a PCP sample that already had assigned Medicaid patients, we considered the representativeness of the sample relative to the typical PCP. As the average US primary care panel size is approximately 1200 to 1900 patients,²⁰ the median number of assigned HMP members per PCP in our sample was 53; with HMP representing approximately one-third of all Michigan Medicaid enrollees, the estimated Medicaid proportion of the panel was approximately 6% to 15% of the total panel size. This is consistent with the national average Medicaid proportion of PCP panels, which has been reported to range from 9% to 20%.^18,21

Survey Development

The survey included standard measures of PCP demographic, professional, and practice characteristics, as well as items from prior surveys on decision making related to Medicaid patients.^10,22 New items related to PCPs’ decisions to accept Medicaid patients in the context of the state Medicaid expansion were developed based on qualitative interviews. Items were subsequently cognitively pretested with 2 PCPs (1 physician from a safety net clinic and 1 PA from a private practice) to ensure understanding prior to survey administration. The final survey was also pretested with 1 PCP to ensure appropriate timing and flow.

Qualitative interviews. To guide survey development and interpretation, we conducted 19 semistructured interviews with a separate group of PCPs caring for Medicaid/HMP patients between December 2014 and April 2015. These interviews were conducted in 5 geographic regions across Michigan, purposefully selected to include racial/ethnic diversity and a mix of urban, suburban, and rural communities: city of Detroit, western Michigan, central lower Michigan, northeastern Michigan, and Michigan’s Upper Peninsula. Interviewees included both physicians and nonphysician providers (ie, NPs/PAs) who worked at small private practices, federally qualified health centers (FQHCs), free/low-cost clinics, hospital-based practices, or rural practices (eAppendix Table 1 [eAppendix available at ajmc.com]).

Interview topics included (1) provider awareness of patients’ insurance and experiences caring for HMP patients; (2) PCP involvement in decision making about whether to accept Medicaid/HMP patients; and (3) factors that may affect PCPs’ Medicaid acceptance decisions in the future, including knowledge of reimbursement changes such as the Medicaid primary care rate bump to the level of Medicare rates in 2013-2014.

Interviews were audio recorded and transcribed verbatim. Each transcript was reviewed iteratively by at least 2 members of the research team, with in-depth coding and thematic analysis^23,24 performed using Dedoose software (SocioCultural Research Consultants, LLC; Manhattan Beach, California).

Survey Administration

The survey was initially mailed to the PCP sample (N = 4322) in June 2015 and included a personalized cover letter describing the project, a fact sheet about HMP, a paper copy of the survey, a $20 bill, and a postage-paid return envelope. The cover letter also gave information on the option to complete the survey online. Two additional mailings with the same contents were sent to nonrespondents in August and September 2015. Data from mailed and online surveys returned by November 1, 2015, were included in the analysis.

Survey Outcomes and Measures

See eAppendix A for the full survey instrument. The dependent variable was PCPs’ current acceptance of new Medicaid or HMP patients (“Are you currently accepting new patients with…[Medicaid; Healthy Michigan Plan; private insurance; Medicare; no insurance (ie, self-pay)]?”). In addition to standard PCP and practice characteristics, survey items measured independent variables of PCP attitudes regarding the importance of various patient- and practice-level factors in their practice’s decision to accept new Medicaid/HMP patients (eg, reimbursement amount, practice capacity to accept any new patients, specialist availability, and illness needs of Medicaid/HMP patients) and their experiences caring for and expressed commitment to caring for underserved populations.

Survey Data Analysis

Descriptive statistics were used to report PCP characteristics, current acceptance of new patients, and responses to other individual survey items. Bivariate and multivariable logistic regression analyses were used to assess the association of independent variables with the dependent variable of continued PCP acceptance of new Medicaid patients (yes/no).

PCP personal, professional, and practice characteristics with statistically significant associations at P <.01 were included as covariates in multivariable analyses, except for cases with expected collinearity (eg, nonphysician provider variable included but not specialty, payer mix variable included but not payment arrangement). For inclusion of items assessing attitudes toward underserved patients in the regression analyses, we created an index across all underserved attitudes items and calculated a score based on agreement level for multiple items (a score of 1 was assigned to a response of strongly disagree, 2 for disagree, 3 for neither agree nor disagree, 4 for agree, and 5 for strongly agree). Scores for individual items were summed to produce a scaled score for which higher numbers represented stronger agreement with commitment to caring for the underserved. A 2-sided P <.05 was considered statistically significant. All analyses were performed using Stata version 13 or 14.2 (Stata Corp; College Station, Texas).

RESULTS

Characteristics of PCP Survey Respondents

After excluding PCPs with undeliverable addresses (n = 501) and who were ineligible (n = 27; eg, retired, moved out of state) from the 4322 surveys sent, the final response rate was 56% (54% for physicians, 65% for NPs/PAs; n = 2104). See eAppendix Figure 1 for a flowchart of survey response rates. There were no significant differences between respondents and nonrespondents with regard to gender, age, number of affiliated Medicaid managed care plans, and practice setting in an FQHC; PCPs with internal medicine specialty were less likely to respond (see eAppendix Table 2 for comparison of PCP survey respondents and nonrespondents).

Nearly half (45%) of respondents were female and 79% were white (Table 1²⁵). Nonphysician providers (NPs/PAs) represented 17% of respondents. Family medicine (53%) and internal medicine (27%) were the most common specialties, and 82% of respondents were board certified. Most respondents (74%) had been in practice for at least 10 years. Fifteen percent practiced in an FQHC, and 35% had a payer mix that was predominantly Medicaid.

PCPs’ Acceptance of New Patients

Although all survey respondents had at least 12 assigned patients with Medicaid/HMP coverage based on the survey sampling, 78% reported continuing to currently accept new Medicaid or HMP patients compared with 87% accepting new patients with private insurance, 84% with Medicare, and 76% with no insurance (Figure 1).

Attitudes Influencing PCPs’ Medicaid Acceptance Decision

Most PCP survey respondents reported having at least some influence on the decision to accept or not accept Medicaid or HMP patients; 23% reported “the decision is entirely mine,” 14% reported “I have a lot of influence,” 21% reported “I have some influence,” and 43% reported “I have no influence.”

In interviews, the 19 PCPs described influences on the Medicaid acceptance decision at various levels (see themes in Table 2). At the provider level, the illness burden and psychosocial needs of prospective Medicaid patients influenced PCPs’ decisions about whether to accept them, particularly for patients with complex chronic pain or mental health needs. At the practice level, the decision to accept new patients depended on the practice’s capacity to provide sufficient care to established patients, including timeliness of appointments and ability to provide high-quality care. At the health system level, PCPs’ decision making depended on the resources and administrative structure of their health system, including whether specialists were available to see Medicaid patients. Lastly, with regard to the policy environment, although most PCPs thought that reimbursement was important, many lacked knowledge of the 2013-2014 ACA primary care rate bump or other payment details yet continued to accept new Medicaid patients.

Based on these themes identified in the qualitative interviews, we asked PCP survey respondents to rate the importance of several patient- and practice-level factors to their practice’s decision to accept new Medicaid or HMP patients (“Please indicate the importance of each of the following for your practice’s decision to accept new Medicaid or Healthy Michigan Plan patients”) (Figure 2). Factors considered very/moderately important to the Medicaid acceptance decision included the capacity to accept new patients with any type of insurance (69%), availability of specialists who see Medicaid patients (56%), reimbursement amount (56%), psychosocial needs of Medicaid patients (50%), and illness burden of Medicaid patients (46%).

We also asked PCP survey respondents about their prior experience and attitudes toward caring for poor or underserved patients. More than half (57%) of respondents reported providing care in the past 3 years in a setting that serves poor and underserved patients with no anticipation of being paid. Nearly three-fourths (73%) felt a responsibility to care for patients regardless of their ability to pay, and nearly three-fourths (72%) agreed or strongly agreed that all practitioners should care for some Medicaid patients (see eAppendix Table 3 for full descriptive statistics of PCP attitudes about caring for underserved patients).

Factors Associated With PCPs’ Medicaid Acceptance

In bivariate analyses, survey respondents were more likely to accept new Medicaid patients if the PCPs were younger, female, racial minorities, specialized in internal medicine, nonphysician providers (NPs or PAs), paid by salary, or working in FQHCs, rural practices, or practices with integrated mental health care or Medicaid-predominant payer mixes (Table 3). Multivariable analyses largely confirmed bivariate analyses: PCP respondents who were female (adjusted odds ratio [aOR], 1.32 vs male; 95% CI, 1.01-1.72), racial minorities (black: aOR, 3.46 vs white [95% CI, 1.45-8.25]; Asian: aOR, 1.84 vs white [95% CI, 1.21-2.80]), nonphysician providers (aOR, 2.21 vs physicians; 95% CI, 1.32-3.71), specialized in internal medicine (aOR, 1.47 vs family medicine; 95% CI, 1.09-1.97), paid by salary (aOR, 2.09 vs fee-for-service; 95% CI, 1.58-2.77), or working in practices with Medicaid-predominant payer mixes (aOR, 7.31 vs private-predominant payer mix; 95% CI, 5.05-10.57) or other nonprivate payer mixes were more likely to accept new Medicaid patients (Table 3).

Regarding PCP attitudes, in bivariate analyses, PCP survey respondents were less likely to accept new Medicaid patients if they deemed that overall capacity to accept new patients was very/moderately important or reimbursement was very/moderately important. Not surprisingly, PCPs were also more likely to accept new Medicaid patients if they had provided prior care to the poor or underserved or expressed a greater commitment to caring for this group. In multivariable analyses, we again found that PCPs who had previously provided care to underserved patients (aOR, 1.35; 95% CI, 1.05-1.73) or who expressed stronger commitment to caring for the underserved (aOR, 1.14 for each point in composite score; 95% CI, 1.11-1.18) were more likely to accept new Medicaid patients. PCPs were less likely to accept new Medicaid patients if they considered overall capacity to accept new patients important (aOR, 0.59; 95% CI, 0.44-0.79).

We then repeated the bivariate and multivariable analyses for the subgroup of PCP survey respondents who indicated that they had at least some influence on the decision to accept Medicaid patients. The findings were similar to those of analyses with the full sample (data not shown).

DISCUSSION

The ACA’s Medicaid expansion has been associated with increased access to care nationally^{2,15,16,26-32} and increased Medicaid acceptance among PCPs in Michigan,¹² even after expiration of the 2013-2014 primary care rate increase of Medicaid fees to Medicare levels.¹³ In our study, we found that PCP demographics, salary structure, history of caring for the underserved, and perceived practice capacity were all associated with continued acceptance of new Medicaid patients among PCPs who already had assigned Medicaid patients.

Our findings on provider characteristics associated with an increased likelihood of Medicaid acceptance were consistent with literature that predated the ACA Medicaid expansion. Specifically, female gender, nonwhite race, and nonphysician professional training (NP or PA) have been associated with greater provider Medicaid acceptance in earlier periods.^{4,5,7,9,33,34} These findings suggest that demographic characteristics of the primary care workforce can influence access for Medicaid patients and that integrating nonphysician providers in primary care practices may be beneficial to ensuring access for Medicaid patients. In fact, an earlier Michigan study found that an increase in Medicaid primary care appointment availability after HMP was associated with rising proportions of appointments offered with NPs or PAs, suggesting that nonphysician providers contributed to improved access.¹³

We also found that PCPs in safety net settings and other practices with Medicaid-predominant payer mixes were more likely to continue accepting new Medicaid patients, confirming findings from prior studies.^3,10,35-37 Of note, FQHCs and rural health clinics receive higher Medicaid reimbursements than private practices. PCPs choosing to work in these safety net settings may be less likely to consider payment amounts important to their decisions to accept additional Medicaid patients.

Unlike in prior studies,^2,3 in our adjusted models, PCP attitudes toward reimbursement were not significantly associated with the likelihood of Medicaid acceptance. Whether this relates to PCPs’ lack of knowledge of reimbursement changes during the rate bump period, as found in our interviews, or other factors is uncertain. Other recent studies have demonstrated no association of the 2013-2014 Medicaid primary care rate bump with physician participation in Medicaid.^21,38 Combined with our findings that experience and commitment to caring for the underserved were associated with PCP acceptance of Medicaid, these results suggest that PCPs who continue to accept Medicaid patients do so, at least in part, out of a sense of professional duty.³⁹ It is possible that this may reflect a population-level shift in attitudes among the current generation of healthcare providers.⁴⁰ To encourage greater provider acceptance of Medicaid, policy makers should consider promoting experiences caring for underserved populations during professional training to broaden the pipeline of future healthcare providers accepting Medicaid.⁴¹

Like other studies, we found that concerns about practice capacity were associated with lower odds of accepting new Medicaid patients.¹⁰ Our qualitative findings demonstrated that PCPs were concerned about scheduling patients both with themselves and with specialists who would accept Medicaid. Interestingly, in our unadjusted model, mental health colocation was associated with PCPs’ continued Medicaid acceptance. This suggests that PCPs who have access to resources for addressing behavioral and social needs may be more willing to accept new Medicaid patients who may have needs for such services that would otherwise be difficult to address in traditional primary care settings. To overcome PCPs’ reported worries about having sufficient time to see their Medicaid patients or having access to Medicaid-accepting specialists for these patients, practice-level innovations targeting appointment scheduling, team-based care, and integration of specialists (eg, mental health professionals) may also facilitate PCPs’ continued acceptance of Medicaid patients.

Limitations

This study has several potential limitations. First, measures are self-reported and prone to social desirability and other survey biases. Particularly regarding willingness of healthcare providers to accept new Medicaid patients, survey self-report may overestimate actual acceptance of new patients.⁴² Second, the sample included only PCPs who were assigned at least 12 HMP enrollees, which may limit generalizability. Decision making regarding acceptance of new patients may differ for PCPs with fewer or no Medicaid patients or for specialists. For example, PCPs with lower baseline numbers of Medicaid patients may place greater importance on reimbursement than PCPs with greater numbers of current Medicaid patients. The focus of this study was on continued acceptance of new Medicaid patients by PCPs with established Medicaid patients, as other studies have found that most increases in PCP Medicaid participation occurred among such providers. Third, we developed a new set of survey items not used in previous studies that assess PCP attitudes toward various factors related to their Medicaid acceptance decision. However, these items were developed based on prior literature and our qualitative interviews with PCPs caring for HMP patients, and they were cognitively pretested with physician and nonphysician PCPs serving HMP patients to ensure understanding and accuracy of responses. Fourth, this study was conducted within the context of a single state’s Medicaid expansion. It is possible that other factors may be relevant to PCPs’ Medicaid acceptance decision in other states, such as Medicaid reimbursement rates or local primary care practice innovations.

CONCLUSIONS

With continued innovation in Medicaid policy at the state and federal levels, identifying provider and practice factors that promote Medicaid acceptance among PCPs will be even more important. This study confirmed several of the same factors considered important to PCPs in prior studies—practice capacity, specialist availability, and medical and psychosocial needs of Medicaid patients&mdash;but in the era after ACA Medicaid expansion. In addition, PCPs in this study placed less emphasis on reimbursement, perhaps because many served in salaried positions, such as safety net clinics, or because they instead emphasized professional commitment to caring for the poor and underserved. To maintain primary care access for low-income patients with Medicaid, future efforts should focus on enhancing the diversity of the PCP workforce, encouraging healthcare professional training in underserved settings, and promoting practice-level innovations in scheduling and integration of specialist care.Author Affiliations: Institute for Healthcare Policy and Innovation (RT, ECK, JZA, CS, SJC, TC, ANH, ES, MAK, SDG), Department of Internal Medicine (RT, JZA, SDG), School of Social Work (ECK), School of Public Health (JZA, SDG), Gerald R. Ford School of Public Policy (JZA), Center for Bioethics and Social Sciences in Medicine (CS, SDG), Department of Pediatrics (SJC), Department of Family Medicine (TC), and Department of Emergency Medicine (ANH), University of Michigan, Ann Arbor, MI; University of Colorado Center for Bioethics and Humanities (EGC), Aurora, CO.

Source of Funding: The study was funded by a contract from the Michigan Department of Health and Human Services (MDHHS) to the University of Michigan to conduct an evaluation of the Healthy Michigan Plan, as required by CMS through a section 1115 Medicaid waiver. The views expressed in this article are those of the authors and do not necessarily reflect the position or policy of MDHHS or CMS.

Author Disclosures: The authors report no relationship or financial interest with any entity that would pose a conflict of interest with the subject matter of this article.

Authorship Information: Concept and design (RT, ECK, JZA, EGC, CS, SJC, TC, SDG); acquisition of data (RT, ECK, EGC, CS, SJC); analysis and interpretation of data (RT, ECK, JZA, EGC, CS, TC, ANH, ES, MAK, SDG); drafting of the manuscript (RT, ANH); critical revision of the manuscript for important intellectual content (RT, ECK, JZA, EGC, CS, SJC, TC, ANH, ES, MAK, SDG); statistical analysis (RT, CS, MAK); obtaining funding (RT, JZA, SDG); administrative, technical, or logistic support (CS, SJC, ES); and supervision (JZA, SDG).

Address Correspondence to: Renuka Tipirneni, MD, MSc, Division of General Medicine, Department of Internal Medicine, University of Michigan, North Campus Research Complex, Bldg 16, Room 419W, 2800 Plymouth Rd, Ann Arbor, MI 48109-2800. Email: rtipirne@med.umich.edu.REFERENCES

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