Mental Health Care Use After Leaving Medicare Advantage for Traditional Medicare

ABSTRACT

Objectives: To evaluate changes in mental health visits and specialties among beneficiaries with at least 1 mental health visit before and after switching from Medicare Advantage (MA) to traditional Medicare (TM).

Study Design: This study examines Medicare beneficiaries with mental health diagnoses who switched from MA to TM in 2018, analyzing their mental health utilization 12 months before and after the switch using MA encounter and TM claims data.

Methods: A longitudinal design was used, comparing mental health visits before and after the switch. We applied Wilcoxon signed rank tests to compare the total number of visits and McNemar tests for specific provider specialties used. Statistical significance was defined as a P value less than .05.

Results: Of the 32,710 beneficiaries who switched from MA to TM in 2018, 1184 beneficiaries (11,015 claims) were included in our sample because they had at least 1 health care visit attributed to a mental health condition both before and after switching. We found a statistically significant increase in the number of mental health visits after switching (P = .014). For the top 5 most prevalent specialties used for mental health care, we found no change in the use of psychiatrists (P = .607) or family medicine specialists (P = .696). However, we found increased use of nurse practitioners (P < .001) alongside decreased use of internal medicine (P = .003) and emergency medicine specialists (P = .001) for mental health care after switching.

Conclusions: Among beneficiaries with continued mental health care utilization, switching from MA to TM was associated with increased mental health visits and a shift in provider composition, which suggests potential care gaps or unmet needs in MA.

Am J Manag Care. 2025;31(12):In Press

Takeaway Points

• Medicare Advantage (MA) insurers use provider networks, which may restrict access to mental health care. This study examines changes in mental health visits and specialties used before and after beneficiaries switch from MA to traditional Medicare (TM).
• We found an increase in the number of mental health visits after switching. We found increased visits with nurse practitioners, decreased visits with emergency medicine and internal medicine specialists, and no change in visits with psychiatrists and family medicine specialists for mental health care.
• These findings provide descriptive evidence of how transitioning from MA to TM is associated with the type of provider specialties used.

Enrollment in Medicare Advantage (MA) has grown rapidly,1 suggesting that beneficiaries may prefer these privately run MA plans to traditional Medicare (TM). One reason for this could be that these plans offer enhanced benefits and additional coverage, which often include dental and vision,2,3 an out-of-pocket maximum spending cap, and non–medically related benefits, such as gym memberships.4-6 Although these benefits in MA can be valuable to beneficiaries, trade-offs exist, especially for beneficiaries with complex health needs. High-need and high-cost beneficiaries7,8 and those who have developed functional disability or Alzheimer disease and related dementias9,10 have increasingly switched from MA back to TM.7 These findings suggest that MA’s advantages may diminish as beneficiaries age or their health conditions worsen. In particular, MA’s managed care strategies, including prior authorization requirements11,12 and provider networks, can create barriers to timely access to care. These barriers may disproportionally affect beneficiaries with certain health issues, including mental health conditions, prompting those beneficiaries to switch back to TM.10,13,14

Mental health care access is a critical issue for MA beneficiaries because the provider networks in MA contracts are often narrow, particularly for mental health services. Whereas beneficiaries in TM can theoretically see any Medicare-accepting provider, MA enrollees are limited to providers in their plan’s network. Prior work has found that more than two-thirds of MA enrollees’ plans included less than 25% of the local Medicare-accepting psychiatrists in their network.15 Additionally, MA plans include a low share of local psychiatrists even when compared with plans in the Medicaid and Affordable Care Act markets.16 Using a prediction algorithm, Feyman et al found that network restrictiveness and access varied by specialty, with psychiatry being in the top 10 most restricted specialties in MA.17 They predicted that MA beneficiaries saw 49% as many psychiatrists as they would without network restrictions.17 This discrepancy in provider access may be particularly burdensome for MA beneficiaries seeking mental health care,18 motivating them to switch to TM where they face fewer restrictions on provider choice.

This article investigates the mental health utilization patterns among beneficiaries who had at least 1 mental health visit before and after switching from MA to TM. By focusing on the intensive margin, we captured how care patterns shift among those who are already engaged in mental health treatment rather than among enrollees who may develop mental health conditions after switching. Using MA encounter data and TM claims, we examined the frequency of mental health visits and the specialty of providers rendering mental health services before and after beneficiaries switched. We aimed to better understand the impact of Medicare plan choice on access to mental health care.

METHODS

Data

We used the 2018 Master Beneficiary Summary File (MBSF) to identify beneficiary monthly enrollment in either TM or MA and beneficiary characteristics. These data are supplemented by the 20% nationally representative sample of the (1) 2017 and 2018 MA encounter files and (2) 2018 and 2019 TM claims carrier (physician offices) files. We further used the 2019 OneKey provider data and merged them with the Medicare claims and encounter data by provider National Provider Identifier (NPI) because the OneKey data included provider specialty information.19

Sample

Beneficiaries were included if they were 66 years and older in 2018, resided in one of the 50 US states or the District of Columbia, and were not dually eligible for Medicare and Medicaid (eAppendix Figure [eAppendix available at ajmc.com]). “Switchers” (those who switched from MA to TM) were identified using 2018 MBSF month-to-month enrollment in either MA or TM.

We sought to build an analytical sample of Medicare beneficiaries with at least 1 mental health visit before and after switching. Focusing on the subset of MA beneficiaries who already had a mental health diagnosis mitigates the new-onset problem (that they are switching to TM because of an incident mental health diagnosis). To identify changes in utilization before and after the switch, we required 12 months of enrollment in MA and TM before and after the switch, respectively. In other words, each individual beneficiary was followed for a total of 24 months, centered around the month during which their switching occurred in 2018. Our sample included beneficiaries who switched in any month in 2018.

To find visits attributed to mental health, we identified the visit’s primary diagnosis code using the International Statistical Classification of Diseases, Tenth Revision (ICD-10) codes. We identified beneficiaries who had a mental health visit by restricting to claims with ICD-10 codes starting with F (ie, mental, behavioral, and neurodevelopmental disorders). The ICD-10 codes, which could be as specific as 5 digits, were combined into higher-level groups for analysis (eAppendix Table 1).

Our sample of health care claims and encounter data was merged with the OneKey provider data by provider NPI, and mental health specialties were identified using the provider specialty information from OneKey. Leveraging the OneKey provider directory data was necessary because the provider NPI specialty variable in the MA encounter data was sparsely populated.

Our final sample included beneficiaries who had at least 1 MA encounter for mental health before switching and at least 1 TM claim for mental health after switching and included provider specialty information from the OneKey data. Additional analyses further restricted the sample to beneficiaries who did not visit a psychiatrist in MA prior to switching.

Outcome Variables

We measured the number of health care visits for mental health conditions as well as the provider’s primary specialty for those visits at any time during the 24-month period during which the beneficiary was first enrolled in MA (12 months) and then enrolled in TM (12 months). For each of the provider primary specialties, we measured the variable as a dichotomous outcome identifying whether the visit was attributed to a specific provider specialty or not. For example, when examining the utilization of psychiatrists, the outcome was whether the mental health visit was attributed to a provider specialty assigned as “psychiatrist.”

Independent Variables

Our primary independent variable was a binary variable, indicating before switching (while the beneficiary was enrolled in MA) or after switching (while the beneficiary was enrolled in TM).

Sensitivity Analyses

To explore potential data quality differences between the TM claims and MA encounter data that may influence our results,20 we limited our data to beneficiaries enrolled in an MA contract identified as highly complete in 2018.21,22 To do this, we identified the MA contract that beneficiaries were enrolled in in January 2018.

To further examine mental health care utilization with psychiatrists, we identified beneficiaries who did not see a psychiatrist while enrolled in MA before switching and then quantified the percentage of those beneficiaries who did see a psychiatrist after switching to TM. To ensure that these results were not due purely to mean reversion, we applied the same inclusion/exclusion criteria to MA beneficiaries who remained in MA for 2 full years (2018 and 2019). Of those who did not see a psychiatrist in 2018, we quantified the percentage who did see a psychiatrist in 2019 while remaining in MA. Although this did not directly mirror the analysis for Medicare switchers because MA “stayers” did not have a “switching month” on which to center their 24-month period of observed health care utilization, this approach generated an analogous sample to test for natural revision to the mean.

Finally, we performed a subgroup analysis by restricting our data to the 2 most prevalent aggregated mental and behavioral health conditions.

Statistical Analysis

We analyzed mental health care utilization using a paired design, as each beneficiary had health care visits recorded both before and after switching from MA to TM. To compare the total number of mental health visits between these 2 periods, we conducted a Wilcoxon signed rank test, appropriate for paired nonparametric data. To assess changes in the utilization of specific provider specialties used for mental health care, we performed McNemar tests for each specialty separately. Statistical significance was defined as a P value less than .05.

Analyses were conducted in Stata 16 (StataCorp LLC) and R 4.2.2 (R Foundation for Statistical Computing). This study was approved by the Johns Hopkins Bloomberg School of Public Health Institutional Review Board (approval #11318).

RESULTS

Of the 32,710 beneficiaries who switched from MA to TM in 2018, 7226 beneficiaries had a health care encounter with a mental health ICD-10 code, and 5730 beneficiaries were included after merging claim-level physician information with the OneKey provider directory using provider NPI. Of those 5730 beneficiaries, 1184 beneficiaries (or 11,015 claims) were included in our sample because they had both an MA encounter for mental health before switching and a TM claim for mental health after switching (Figure 1). Because our sample decreased with each exclusion criteria, we compared key beneficiary characteristics across the different sample groups. We found no large differences between the sample groups for the distribution of sex, age group, or race or the mean number of comorbidities (Table 1).

We compared the distribution of mental health visits by ICD-10 grouping for the 1184 beneficiaries with both MA encounter and TM claims before and after switching, respectively. For that sample, most of the encounters were for mood disorders, which include major depressive disorder and bipolar disorder. Physiological conditions, anxiety and stress, and schizophrenia were the second, third, and fourth most prevalent reasons for mental health visits, respectively (Figure 2). Next, we compared the distribution of specialists for the health care visits for mental health conditions. The most prevalent provider type, regardless of whether the beneficiary was enrolled in MA or TM, was psychiatry, followed by family medicine, internal medicine, nurse practitioner, and emergency medicine (Figure 3).

In our sample, beneficiaries had a median (IQR) of 8 (4-18) mental health visits in MA before switching and 9 (4-21) visits in TM after switching. The mean (SD) number of visits per beneficiary with psychiatrists was 1.4 (4.2) in MA before switching and 1.7 (5.3) in TM after switching (Table 2). To contextualize these utilization patterns, we compared mental health care utilization for beneficiaries who stayed in TM or MA only, who were outside of our sample. We found median (IQR) values of 11 (4-24) and 7 (3-16) mental health visits for TM and MA beneficiaries, respectively (eAppendix Table 2).

Using the sample of 1184 beneficiaries (11,015 claims) who had mental health care claims both in MA before switching and in TM after switching, we found a statistically significant increase in the number of mental health visits before and after switching (Wilcoxon signed rank test: P = .014). Leveraging the McNemar test for the top 5 most prevalent provider specialties, we found no statistically significant difference in the use of psychiatrists (P = .607) or family medicine specialists for mental health care (P = .696). However, we did find a statistically significant increase in visits with nurse practitioners (P < .001) and decreases in visits with internal medicine (P = .003) and emergency medicine specialists (P = .001) (Table 2). The mean number of mental health visits with a nurse practitioner was 0.54 before switching and 1.01 after switching—or 87% higher after switching to TM (Table 2). Relatedly, we found that the share of mental health care services delivered by nurse practitioners increased by 8.2 percentage points after switching from MA to TM (from 12.3% before switching to 20.5% after) (Figure 3). Visits with internal medicine and emergency medicine specialists decreased by 24.2% and 26.1%, respectively.

Sensitivity Analyses

When we restricted our analysis to beneficiaries enrolled in an MA contract identified as highly complete, the number of unique beneficiaries was reduced from 1184 to 859 (72.6% unique beneficiaries remained in our sample). We found no large differences between the mean number of mental health care claims, percentage of female beneficiaries, distribution of age group or race categories, or measure of comorbidity (eAppendix Table 3). Additionally, our results remained largely consistent. We found that the number of mental health care visits increased after switching (P = .017) and that visits with nurse practitioners increased (P < .001) while those with emergency medicine specialists decreased (P < .001) (eAppendix Table 4).

For the 821 beneficiaries who did not see a psychiatrist in MA prior to switching, we observed that 10% of them saw a psychiatrist after switching. For the 258,997 MA stayers who did not see a psychiatrist in 2018, we observed that 2.1% of them saw a psychiatrist in the subsequent year.

Focusing on the subset of beneficiaries diagnosed with physiological conditions, we found slightly different results. Overall number of mental health visits remained consistent (P = .339), but visits with nurse practitioners increased (P = .001) and those with emergency medicine specialists decreased (P < .001) after switching. eAppendix Table 5 and eAppendix Table 6 show subgroup analysis results for our sample restricted to physiological conditions and mood disorders, respectively.

DISCUSSION

In this retrospective, claims-based analysis, we identified MA beneficiaries who received a health care service coded to a mental health ICD-10 code both before and after switching to TM. We observed an increase in the total number of mental health visits. Although we observed no statistically significant increase in the utilization of psychiatry or family medicine specialties, we did find greater utilization of nurse practitioner care and less utilization of internal medicine and emergency medicine specialties for mental health services after enrollees switched to TM.

These results suggest several important dynamics related to mental health care utilization and access for beneficiaries who switch from MA to TM. First, we observed a slightly greater number of mental health visits for our sample after beneficiaries switched from MA to TM. Beneficiaries in TM are not limited by provider networks and are generally subject to fewer prior authorization policies to see specialists.

Second, the lack of significant differences in the use of psychiatry or family medicine suggests that beneficiaries who switch from MA to TM do not drastically alter overall care-seeking behavior within these specialties. Beneficiaries who switch from MA to TM may have established a preference or relationship with a mental health care provider that persists across systems. Although this may be true, we did find that for the 821 beneficiaries who did not see a psychiatrist while in MA, 10% of them saw a psychiatrist after switching to TM. For the group who stayed in MA, only 2% of beneficiaries who did not see a psychiatrist the prior year then saw a psychiatrist. Taken together, these results suggest that beneficiaries in MA may switch to TM for broader access to psychiatrists.

Third, our results suggest that there is an increased role of nonphysician providers in TM. The increased utilization of nurse practitioners suggests that TM may provide greater access to nonphysician mental health care providers, which could be critical to addressing gaps in care or improving timeliness of services. In TM, Medicare reimburses nurse practitioners at 85% of the physician fee schedule rate for the same services, meaning that nurse practitioners receive a lower payment for comparable procedures than doctors, although the exact payment differential varies at the state level. A scoping review found that care provided by psychiatric mental health nurse practitioners was generally associated with positive patient outcomes,23 although more research is needed to understand their delivery of care in the Medicare setting.

Another important aspect is the beneficiary’s access to supplemental insurance in TM, or Medigap. Most beneficiaries who disenroll from MA are subject to individual rating of Medigap premiums, and Medigap insurers can deny coverage outright or effectively deny coverage through high premiums.24 Thus, those beneficiaries who still choose to disenroll, even when faced with potentially high Medigap premiums, may be different than the beneficiaries who remain “trapped” in MA.25 Future work could examine how beneficiaries’ mental health utilization patterns compare between switchers and stayers by state-level Medigap policies.

This work is, to the best of our knowledge, the first to examine the intensive margin of mental health utilization focusing on provider specialties utilized by Medicare beneficiaries who switch from MA to TM. Given the movement of mental and behavioral health care providers to cash-pay models, future research should explore the role of cash-pay mental health care providers on Medicare beneficiaries’ care access. Finally, the MA encounter data are incomplete, and many of the NPI variables were missing or did not successfully merge with provider directory data. Comprehensive and accurate MA encounter data will significantly improve the research landscape around the topic of MA beneficiaries’ access to specialty care. Although this descriptive work is an important first step in understanding specialty care access for Medicare beneficiaries, future work could include qualitative interviews with Medicare beneficiaries and quantitative, causal analyses.

Limitations

This study has limitations. First, health care utilization patterns for mental health can change for various reasons, and our analysis did not isolate these underlying drivers. For instance, beneficiaries may switch from MA to TM in response to a new mental health diagnosis, which could independently influence their utilization of services and specialists. We mitigated this limitation by focusing our analytic sample on beneficiaries who had at least 1 mental health visit in MA prior to switching. Although future research is needed to disentangle these pathways, this study provides foundational empirical evidence on mental health care utilization before and after switching Medicare coverage—a critical first step in understanding these patterns. Second, although the use of TM claims and MA encounter data allowed us to capture a large sample, we could only observe health care utilization, which is a proxy for demand. There may be beneficiaries who seek mental health resources but are unable to access them, and these cases would not be captured in our data. Third and finally, merging the data with OneKey to identify provider specialty dropped many of the claims and encounters, so results may not be generalizable outside the sample included in our analysis.

CONCLUSIONS

Using claims-level data, we analyzed longitudinal beneficiary-level mental health care visits and specialties used for beneficiaries who had at least 1 mental health care visit before and after switching from MA to TM. We found a greater number of mental health visits in TM after switching. Examining provider specialties, we found an increase in visits with nurse practitioners and a decrease in visits with internal medicine and emergency medicine specialists. We further found that some beneficiaries who did not see a psychiatrist before switching did see a psychiatrist after switching, underscoring the potential barriers that MA beneficiaries might face in accessing specialty mental health care. Future research should explore these regulatory dynamics around mental health care access, particularly at the insurer and plan levels, to ensure access to mental health care for all Medicare beneficiaries. 

Author Affiliations: Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health (AL, MKM), Baltimore, MD; CMS (BA), Woodlawn, MD.

Source of Funding: Arnold Ventures (grant G146501), Agency for Healthcare Research and Quality (grant T32HS000029), and National Institute of Mental Health (grant K01MH137322). The views presented herein do not represent the views of Arnold Ventures or of the federal government.

Author Disclosures: Dr Liu reports receiving consulting fees from Robbins Geller Rudman & Dowd LLP for unrelated work as an expert witness. The remaining 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 (AL, BA); analysis and interpretation of data (AL, BA, MKM); drafting of the manuscript (AL, BA, MKM); critical revision of the manuscript for important intellectual content (AL, MKM); statistical analysis (AL, BA); provision of patients or study materials (AL); administrative, technical, or logistic support (AL); and supervision (AL).

Address Correspondence to: Angela Liu, PhD, Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe St, Office W7503C, Baltimore, MD 21205. Email: aliu63@jh.edu.

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