Effects of High Deductible Health Plans on Enrollees with Mental Health Conditions with and without Substance Use Disorders

Abstract

Objective:

High-deductible health plans (HDHPs) are increasingly common in the U.S. health insurance market and are intended to reduce the use of low-value services, but evidence suggests HDHP enrollees also reduce use of high-value services. This study examined the effects of HDHPs on enrollees with mental health conditions, a population with high levels of unmet treatment need, often due to financial barriers. Enrollees with a co-occurring substance use disorder have greater treatment needs and unique barriers to care, perhaps changing their response to a HDHP.

Methods:

Commercial health insurance claims data in a difference-in-differences design was used to evaluate the effect of an employer offering a HDHP on 6,627,128 enrollee-years with mental health conditions, stratified by having a co-occurring substance use disorder or not.

Results:

Among enrollees without a co-occurring substance use disorder, a HDHP offer was associated with a 4.8% (95% CI: 2.4, 7.2) reduction in overall spending on mental health care, despite a 11.3 percent (95% CI 1.0, 21.6) increase in spending on mental health-related emergency department visits. Among enrollees with a co-occurring substance use disorder, no significant changes attributable to a HDHP offer were found in most categories of spending on combined mental health and substance use disorder care, apart from a 4.5% (95% CI: 1.9, 7.2) reduction in spending on psychotropic medications.

Conclusions:

HDHPs may reduce use of necessary care among enrollees with mental health conditions, which could exacerbate undertreatment in this population and result in adverse health outcomes.

Introduction

In 2018, an estimated 19 percent of US adults reported having a mental health condition in the last year (1). Among them, an estimated 19 percent also had a substance use disorder (1). The population with mental health conditions and a co-occurring substance use disorder has grown 12 percent from 2014 to 2018 and tends to include those with more severe mental health conditions and medical comorbidities (1, 2). Mental health conditions and substance use disorders can be effectively managed as chronic conditions, but care is often underutilized and poorly integrated with the broader healthcare system (3). Only 43 percent of adults with a mental health condition, and 51 percent of adults with both mental health conditions and a substance use disorder, report receiving treatment for either their mental health conditions or substance use disorders within a year, and financial barriers are a primary factor contributing to foregone care (1, 4, 5).

High deductible health plans (HDHPs) comprise an increasing proportion of the employer-sponsored health insurance market (6). In 2019, nearly 30 percent of Americans in this market were enrolled in a HDHP, with deductibles in these plans averaging $2,476 (6). HDHPs are intended to motivate enrollees to control costs by avoiding low value health care, but enrollees have been shown to cut care indiscriminately (7). For those with chronic conditions, such as mental health conditions, skipping or delaying necessary care could lead to negative health consequences (8–10).

Among commercial health plan enrollees with mental health conditions or substance use disorders, those enrolled in HDHPs tend to have higher out-of-pocket spending on health care costs annually, but have lower total health care expenditures than non-HDHP enrollees (11–13). Among those with bipolar disorder, one study found that HDHPs were associated with a significant reduction in non-psychiatrist outpatient mental health visits but not with reductions in psychiatrist visits, medications, hospitalizations, or emergency department care (14). HDHPs might differentially affect those with both a mental health condition and a substance use disorder. Among those with mental health conditions, those with a co-occurring substance use disorder more frequently indicate that their mental health conditions interfere with daily activities and more often have other conditions requiring medical care, such as heart disease, respiratory disorders, and gastrointestinal disorders (1, 2, 15, 16). Those with co-occurring substance use disorders face unique barriers to accessing care and more often require higher levels of intensive care, such as inpatient and emergency services, that might be less sensitive to cost-sharing (5, 17, 18). The severity and multitude of conditions, the types of care received, and existing barriers to care associated with substance use disorders may contribute to differences in how enrollees with mental health conditions respond to HDHPs.

We would expect treatment to decrease among all enrollees with mental health conditions in response to HDHPs. We explored whether enrollees with a co-occurring substance use disorder differ in their response to a HDHP compared to those with mental health conditions alone. Given their higher care needs and likelihood of meeting their deductible earlier in the year, enrollees with a co-occurring substance use disorder may decrease utilization to a lesser extent than those with mental health conditions alone. On the other hand, the financial barriers associated with high deductibles combined with existing barriers to treatment may lead enrollees with a co-occurring substance use disorder to reduce their care to a greater extent.

The limited research on the implications of HDHPs for populations with mental health conditions points to potential reductions in service use and heightened financial burden for these populations (11, 14, 19). We built on this literature with a quasi-experimental evaluation of the effect of HDHPs on commercial health insurance enrollees in the United States with a broad range of mental health conditions and explored the extent to which effects differ among those with a co-occurring substance use disorder.

Methods

In this study, we conducted a difference-in-differences analysis examining the effect of a firm’s decision to offer a HDHP to its enrollees on health care spending and utilization among enrollees with mental health conditions, stratified by whether the enrollee had a co-occurring substance use disorder. This study was approved by the Institutional Review Board of Johns Hopkins University.

Study Data

We used de-identified employer-sponsored commercial health insurance claims and detailed benefit design data from the OptumLabs® Data Warehouse (OLDW) from 2007 to 2017 to analyze enrollee health care spending (20). Insurance claims included enrollee and health plan spending for inpatient, outpatient, and pharmacy services for enrollees in plans with medical, pharmacy, and mental health coverage. Benefit design data included in-network medical deductibles, pharmacy deductibles, and blinded firm-level identifiers.

Analytic Sample

Our analytic sample included enrollees with a mental health condition during the period 2007–2017 at firms that began offering or never offered a HDHP. We defined firms that did not offer a HDHP and then began offering a HDHP as treatment firms and firms that never offered a HDHP during the study period as comparison firms. (21)

We excluded enrollee-years with Medicare or without medical, pharmacy, or mental health coverage. We included enrollees 12–64 years who were continuously enrolled with valid deductible and demographic information for at least 11 months within a calendar year. Large changes in the number of enrollees at a firm may indicate that enrollees switched to health plans unobserved in this data, so we only included enrollees at firms with stable firm size (<50% change) year over year.

To designate a plan as a HDHP, we used the U.S. Internal Revenue Service’s definition of the minimum individual deductible that is allowed for a plan to also have a health savings account, which varies year to year but averaged $1,214 during our study period. We calculated the proportion of enrollees at the firm enrolled in a HDHP and identified treatment firms as those that had at least 1 year with none or very few (< 5%) of its enrollees enrolled in a HDHP followed by at least 1 year with a greater share (>5%) of its enrollees enrolled in a HDHP, following prior literature (22, 23). We designated firms with 0% of enrollees in HDHPs in all years during the study period as comparison firms.

Within these treatment and comparison firms, we restricted our sample to enrollees with a mental health condition. Following other work, we included enrollees in our analytic sample if they had at least one claim with a mental health diagnosis during the current or a previous year using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes 295–302, 306–314 and ICD-10-CM codes F20-F69, F84, F90-F99 (24).

We identified enrollees that also had at least one claim with a substance use disorder diagnosis using ICD-9-CM codes 291, 292, 303, 304, and 305 (excluding 305.1 tobacco use disorder and 305.8 antidepressant abuse) and ICD-10-CM codes F10-F19 (excluding F17.2x tobacco use disorder). Enrollees that had both a mental health and substance use disorder diagnosis at any point during the study period were categorized as having a co-occurring disorder the first year with either a mental health or substance use disorder diagnosis and in all subsequent years. We ensured that treatment and comparison firms had a similar proportion of enrollee-years included in the sample both before and after HDHP offer. Detailed sample selection specifications and criteria are in Appendix 1.

Measures

Our outcomes included annual spending on combined mental health and substance use disorder care and annual spending on non-mental health and non-substance use disorder care. We calculated annual spending on combined mental health and substance use disorder care by summing spending on claims with a primary diagnosis for a mental health condition or substance use disorder and spending on claims for psychotropic medications and medications to treat substance use disorders. We calculated annual spending on non-mental health and non-substance use disorder care as all other claims. Within the combined mental health and substance use disorder category and the non-mental health and non-substance use disorder care category, we separately calculated spending associated with inpatient hospitalizations, emergency department use, outpatient evaluation and management (E&M) services, and medications. For enrollees with a co-occurring substance use disorder, we separately calculated spending on medications to treat substance use disorder and psychotropic medications. We top-coded spending at the 99.9th percentile.

We calculated the total days’ supply for psychotropic medications and the average spending per days’ supply of psychotropic medication throughout the year. Among enrollees without a co-occurring substance use disorder, we calculated the number of E&M visit days and the average spending per E&M visit day throughout the year for both mental health and non-mental health E&M visits. Additional details on outcome construction are in Appendix 2.

Our main independent variable was a firm-level flag indicating that an enrollee-year was at a treatment firm interacted with a flag indicating that the enrollee-year occurred after the HDHP offer (i.e., the ‘post’ period among treatment firms). This interaction provides our estimated effect of the impact of a HDHP offer on outcomes.

Statistical Analysis

We estimated two-way fixed effects models for enrollees with mental health conditions stratified by the presence of a co-occurring substance use disorder. Calendar year fixed effects controlled for secular trends and firm fixed effects controlled for time-invariant firm-level differences. Differences between enrollees at treatment and comparison firms on a range of covariates were minimal (with standardized mean differences below 0.1, see Appendix 3), but our models controlled for age, gender, race, census division geography, household income level, median Census-block education level, and Chronic Conditions Warehouse’s chronic medical conditions (25, 26). Ordinary least squares (OLS) regression models were used for all outcomes. Standard errors were clustered at the firm level. All analyses were conducted in Stata 16 (27).

Results

Sample Characteristics

Table 1 displays unadjusted descriptive characteristics of enrollees with a mental health condition with and without a co-occurring substance use disorder before and after a HDHP offer at treatment and comparison firms. Mean annual total healthcare spending among enrollees with a co-occurring substance use disorder was $15,637, nearly twice that of enrollees without ($7,912). Among enrollees with mental health conditions at firms that offered a HDHP, 43% of enrollees with a co-occurring substance use disorder, and 46% of enrollees without, enrolled in a HDHP.

Table 1:

Unadjusted Descriptive Characteristics of Health Plan Enrollees Offered and Not Offered a HDHP with Mental Health Conditions with and without a Co-Occurring Substance Use Disorder Before and After HDHP Offer, 2007–2017

	Mental Health Conditions with a Co-Occurring Substance Use Disorder					Mental Health Conditions without a Co-Occurring Substance Use Disorder
	Offered HDHP		Not Offered HDHP		Entire Sample	Offered HDHP		Not Offered HDHP		Entire Sample
	Pre Period	Post Period	Pre Period	Post Period		Pre Period	Post Period	Pre Period	Post Period
Sample Size, N	127,730	204,992	141,209	124,619	598,550	1,189,147	2,041,209	1,524,307	1,273,915	6,028,578
Age
Mean	37.2	38.1	37.1	37.8	37.6	39.7	40.0	39.4	39.5	39.7
SD	14.3	14.5	14.2	14.4	14.4	14.0	14.4	14.0	14.3	14.2
Sex, %
Male	53.0	53.7	54.6	54.7	54.0	37.2	38.6	38.8	39.9	38.6
Female	46.9	46.3	45.4	45.3	46.0	62.8	61.4	61.2	60.1	61.4
Race/Ethnicity, %
White	69.8	67.7	69.8	65.9	68.4	68.7	66.4	68.3	64.4	67.1
Black	8.7	8.6	7.6	8.1	8.3	9.7	9.7	7.5	7.8	8.7
Hispanic	7.1	6.7	7.7	8.2	7.3	7.4	7.1	9.1	9.4	8.2
Asian	1.4	1.5	1.3	1.4	1.4	2.5	2.7	2.2	2.4	2.5
Missing/Unknown	13.0	15.4	13.5	16.3	14.6	11.7	14.1	12.9	16.1	13.6
Count of Chronic Conditions
Mean	1.0	1.0	1.0	1.1	1.0	0.9	0.8	0.8	0.8	0.8
SD	1.6	1.6	1.6	1.7	1.6	1.3	1.3	1.3	1.3	1.3
All Healthcare Utilization
Mean $	14,485	16,303	14,922	16,638	15,637	7,822	8,089	7,510	8,220	7,912
Mental Health & Substance Use Disorder Spending, mean $
Total	2,970	3,404	3,143	3,504	3,264	823	677	800	766	761
Hospitalizations	800	939	866	971	897	57	52	52	55	54
Emergency Department Visits	138	140	186	163	157	21	15	31	21	23
Outpatient Evaluation & Management Services	155	185	152	184	170	73	75	71	85	76
Medications	918	834	910	857	877	476	384	461	421	433

NOTES: Comparison group means are constructed using the weighted average of comparison group characteristics across calendar years weighted by the proportion of which those calendar years appear in the treatment sample during the pre and post periods. Chronic conditions are derived from the Chronic Conditions Warehouse (CCW). Count of chronic conditions excludes all mental health and substance use disorder-related conditions and ranges from 0 to 21. All Healthcare Utilization includes mental health, substance use disorder, and all other health care spending. Full sample characteristics and covariate balance statistics are available in Appendix 3.

Effects of HDHPs on Health Care Spending

Figure 1 displays estimates of percent changes in spending on combined mental health and substance use disorder care associated with a firm’s decision to offer a HDHP among enrollees with mental health conditions. We estimated that a HDHP offer is associated with a $40 (95% CI: 20, 59) average annual reduction in spending on all mental health care among enrollees without a co-occurring substance use disorder. With average annual spending on mental health care before a HDHP offer totaling $821, this corresponds to a 4.8 percent (95% CI: 2.4, 7.2) reduction attributable to a HDHP offer. We also estimated a 9.1 percent (95% CI: 2.7, 15.4), or $7, reduction in spending on mental health outpatient E&M services, a 4.8 percent (95% CI: 2.4, 7.3), or $23, reduction in spending on psychotropic medications, and a 11.3 percent (95% CI 1.0, 21.6), or $3, increase in spending on mental health-related emergency department visits among enrollees without a co-occurring substance use disorder.

Figure 1: Estimated Percent Change in Spending for Mental Health and Substance Use Disorder Care Attributable to a HDHP Offer Among Enrollees with Mental Health Conditions with and without a Co-Occurring Substance Use Disorder, 2007–2017.

NOTES: Total spending refers to all mental health and substance use disorder care spending. Treatment setting subcategories (inpatient, emergency department, outpatient evaluation & management, and medication) are not exhaustive and do not sum to total combined mental health and substance use disorder care spending. To obtain percent changes, OLS model coefficients, representing changes in dollar amounts, were divided by pre-period mean spending levels at treatment firms. Covariates included age, gender, 9-level census division, race/ethnicity indicators, household income, median education at the census-block level, chronic medical condition indicators, calendar year fixed effects, and firm fixed effects. Full model results are found in Appendix 4.

Adjusted mean annual spending levels for psychotropic medications and medications to treat substance use disorders before and after a HDHP offer among enrollees with a co-occurring substance use disorder are displayed in Figure 2. A 3.7 percent (95% CI: 1.2, 6.2), or $34, reduction in combined spending on these medications was driven by a $25 (95% CI: 7, 44) reduction in spending on psychotropic medications in the year following the HDHP offer that was sustained in the following year. Spending on medications for substance use disorders remained unchanged.

Figure 2: Adjusted Annual Spending on Psychotropic Medications and Medications to Treat Substance Use Disorders Among Enrollees with Mental Health Conditions and a Co-Occurring Substance Use Disorder Three Years Before and After a HDHP Offer, 2007–2017.

NOTES: Medication spending includes pharmacy spending and medications administered by a clinician. OLS model covariates included age, gender, 9-level census division, race/ethnicity indicators, household income, median education at the census-block level, indicators for chronic medical conditions, calendar year fixed effects, and firm fixed effects. Full model results are found in Appendix 4.

Figure 3 displays estimates of changes in spending on non-mental health and non-substance use disorder care associated with a HDHP offer among enrollees with mental health conditions. Among enrollees without a co-occurring substance use disorder, an estimated 1.9 (95% CI: 0.4, 3.3) percent, or $128, average annual reduction in spending was detected for non-mental health care. Likewise, an estimated 2.7 percent (95% CI 1.1, 4.2), or $18, reduction in spending on non-mental health outpatient E&M services was associated with a HDHP offer. We detected an estimated 4.7 percent (95% CI: 2.3, 7.0), or $39, reduction in annual spending on non-mental health and non-substance use disorder outpatient E&M services among enrollees with a co-occurring substance use disorder.

Figure 3: Estimated Percent Change in Spending for Non-Mental Health and Non-Substance Use Disorder Care Attributable to a HDHP Offer Among Enrollees with Mental Health Conditions with and without a Co-Occurring Substance Use Disorder, 2007–2017.

NOTES: Total spending refers to all non-mental health and non-substance use disorder spending. Treatment setting subcategories (inpatient, emergency department, outpatient evaluation & management, and medication) are not exhaustive and do not sum to total non-mental health and non-substance use disorder spending. To obtain percent changes, OLS model coefficients, representing changes in dollar amounts, were divided by pre-period mean spending levels at treatment firms. Covariates included age, gender, 9-level census division, race/ethnicity indicators, household income, median education at the census-block level, chronic medical condition indicators, calendar year fixed effects, and firm fixed effects. Full model results are found in Appendix 4.

The observed reduction in spending on psychotropic medications for enrollees with mental health conditions was driven by a 4.2 percent (95% CI: 0.9, 7.4), or 8.1 day, reduction in quantity of the days’ supply of these medications within a year for those without a co-occurring substance use disorder and a 2.7 percent (95% CI: 0.1, 5.1), or 7.6 day, reduction for those with a co-occurring substance use disorder (Figure 4). Similarly, we found a 7.9 percent (95% CI: 3.6, 12.2), or 0.07 visit day, reduction in mental health outpatient E&M visits and a 2.4 percent (95% CI: 1.1, 3.6), or 0.12 visit day, reduction in non-mental health outpatient E&M visits among enrollees without a co-occurring substance use disorder. We did not detect changes in the cost per unit of these medications or services associated with a HDHP offer. Full model results for Figures 1–4 are available in Appendix 4.

Figure 4: Estimated Percent Change in the Quantity and Price of Psychotropic Medications and Outpatient Evaluation and Management Visits Attributable to a HDHP Offer Among Enrollees with Mental Health Conditions, 2007–2017.

NOTES: The top panel measures the percent change of the quantity of days’ supply within a year and the total cost per days’ supply of psychotropic medications among enrollees with and without a co-occurring substance use disorder. The bottom panel measures the percent change of the number of visit days for outpatient E&M services among enrollees without a co-occurring substance use disorder and the cost per the associated claims on those visit-days. Costs included the amounts paid out-of-pocket by the enrollee and by the health plan. To obtain percent changes, OLS model coefficients, representing changes in either quantity or cost per quantity (price) were divided by pre-period means. Models measuring changes in price do not include enrollee-years that did not have any care in the corresponding category. Covariates included age, gender, 9-level census division, race/ethnicity indicators, household income, median education at the census-block level, chronic medical condition indicators, calendar year fixed effects, and firm fixed effects. Full model results are found in Appendix 4.

Differences in Effect of HDHP Offer

We compared the percent changes associated with a HDHP offer on health care spending among enrollees with mental health conditions with and without a co-occurring substance use disorder, displayed in Figures 1 and 3, and found these changes to be largely similar.

Sensitivity Analyses

We conducted a number of sensitivity analyses varying firm-level thresholds used in identifying treatment firms, sample specifications, top-coding thresholds, and modeling approaches and found these results are qualitatively similar in all specifications (Appendix 5).

Discussion

In this study, we explored how HDHPs affect those with mental health conditions with and without a co-occurring substance use disorder. We found that all enrollees with mental health conditions reduce spending in some treatment categories when offered a HDHP, primarily for outpatient E&M services and psychotropic medications. These findings are largely consistent with previous studies evaluating HDHPs that have demonstrated reductions in office visits and medication use for other chronic conditions (22, 28–30).

It is not clear why a HDHP offer was associated with reductions in spending on psychotropic medications but not for spending on medications for substance use disorders or other medical conditions. Our estimate of a reduction in psychotropic medication spending associated with a HDHP offer differs from one recent HDHP study, which found no decrease in utilization of medications for the treatment of bipolar disorder (14). It is possible that the decreases in spending we observed were driven by medications for less severe mental health conditions. Other work has shown cost sharing induced reductions in the utilization of antidepressants and documented greater price responsiveness for antidepressants compared to medications to treat serious mental illness (31, 32).

Prior literature exploring HDHPs primarily suggests reductions or no changes in the utilization of emergency department services, but some studies have found increases in emergency department utilization among sicker and less wealthy enrollees (7, 10, 33, 34). In this study, we found a decrease in spending on outpatient E&M services and psychotropic medications coupled with an increase in spending on mental health-related emergency department visits, suggesting that a HDHP offer may be associated with forgoing or limiting necessary mental health care, possibly resulting in adverse events. This is potentially worrisome and needs further study.

Our study has several important limitations. First, despite the rigorous quasi-experimental study design, the study was observational and enrollees were not randomized to HDHP and non-HDHP plans. Because the decision by an enrollee to select a HDHP is not random and is likely associated with other characteristics of the enrollee, we instead focused on the employer’s choice to offer a HDHP to mitigate this selection bias. Additionally, the likelihood of receiving mental health or substance use disorder care, and therefore the likelihood of entering the sample, might have been influenced by enrollment in a HDHP. To mitigate any potential biases, we ensured our clinical criteria was balanced across treatment groups (Appendix 1) and conducted sensitivity analyses requiring enrollee-level fixed effects (Appendix 5), which produced consistent findings. Second, our analytic strategy relied on the assumption that outcome trends at comparison firms are an appropriate approximation for what would have happened at firms that offered a HDHP had they not offered a HDHP. This cannot be directly tested, but outcome trends tested using event study models were generally parallel in the years directly preceding a HDHP offer, with few exceptions (e.g., psychotropic medications). Findings were also consistent in these event study models (Appendix 6). Third, with a somewhat higher proportion of enrollees in the South and Central regions, our results may not be generalizable to the broader employer-sponsored health insurance market. Fourth, the data used in this study did not capture those services for which enrollees paid cash only and not all substance use disorder treatment may be accompanied by a diagnosis code, potentially affecting sample selection. A sensitivity analysis that used alternative substance use disorder sample selection criteria yielded consistent results (Appendix 5) (35). Lastly, this study focused on the impact of deductible levels only and did not account for other cost-reduction tools that might have been implemented by the employer at the time of the HDHP offer. While other studies have incorporated other tools into analyses for a small number of employers, our study has the benefit of examining a large and heterogeneous group of employers over a long study period (8).

Conclusion

Our findings suggest that HDHPs lead those with mental health conditions to reduce the use of needed medications and outpatient care. Policymakers, employers, clinicians and health systems should consider the ways in which insurance design leads enrollees with mental health conditions to restrict care, with potentially detrimental health consequences.

Highlights.

• An employer-offered high-deductible health plan (HDHP) was associated with a 4.8% reduction in spending on mental health care among enrollees with mental health conditions.

• An employer-offered HDHP was associated with a 1.9% reduction in spending on non-mental health care among enrollees with mental health conditions.

• An employer-offered HDHP was associated with a decrease in spending on psychotropic medications, but not medications to treat substance use disorder, among enrollees with mental health conditions and a co-occurring substance use disorder.