Reducing Behavioral Inpatient Readmissions for People with Substance Use Dis s: Do Follow-up Services Matter?

Sharon Reif, Ph.D.a, Andrea Acevedo, Ph.D.a, Deborah W. Garnick, Sc.D.a, and Catherine Fullerton, M.D., M.P.H.b

aInstitute for Behavioral Health; Heller School for Social Policy and Management; Brandeis University; 415 South Street, MS 035; Waltham, MA 02453 USA

bTruven Health Analytics Inc.; 150 Cambridgepark Drive, Cambridge, MA 02140 USA

Abstract

Objective—Individuals with substance use dis s are at high risk for hospital readmission. This study examined whether targeted follow-up services received within 14 days postdischarge

from an inpatient hospital stay or residential detoxification reduced readmissions within 90 days,

among Medicaid beneficiaries who had an index substance use dis diagnosis.

Methods—Claims data were analyzed for Medicaid beneficiaries aged 18–64 years with a substance use dis diagnosis coded as part of an inpatient hospital stay or residential

detoxification in 2008 (N=30,439). Follow-up behavioral health services included residential,

intensive outpatient, or outpatient treatment, and/or medication-assisted treatment (MAT).

Analyses included 10 states or fewer based on a minimum number of index admissions and

prevalence of follow-up services or MAT. Survival analyses with time-varying independent

variables were used to test the association of follow-up services and MAT with behavioral health

readmissions.

Results—Two-thirds of individuals with an index admission had no follow-up services within 14 days. Behavioral health admissions 90 days postdischarge were present for 29% of individuals

with an index admission. Survival analyses showed that MAT and residential treatment were

associated with reduced risk of behavioral health admission in the 90 days postdischarge.

However, outpatient was associated with increased risk of readmission, as was intensive outpatient

in one model.

Conclusions—Provision of MAT or residential treatment for substance use dis s after an inpatient or detoxification stay may help prevent future readmissions. Medicaid programs should

be encouraged to reduce barriers to MAT and residential treatment to prevent future behavioral

health admissions.

INTRODUCTION

Reducing hospital readmissions is an increasing focus of health care quality improvement

and cost-reduction strategies.1 Readmission rates for individuals with substance use

dis s are relatively high (18–26%).2 Having a substance use dis is linked to greater

complexity of care and hospital-related complications, longer lengths of stay, and greater

likelihood of readmissions even when addiction treatment is not the reason for

HHS Public Access Author manuscript Psychiatr Serv. Author manuscript; available in PMC 2018 August 01.

Published in final edited form as: Psychiatr Serv. 2017 August 01; 68(8): 810–818. doi:10.1176/appi.ps.201600339.

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hospitalization.3–8 Further, they are associated with other health consequences and higher

health services costs.3,9,10 Among Medicaid beneficiaries, alcohol and drug use dis s

were among the top ten conditions with the most all-cause 30-day readmissions.2 For

Medicaid beneficiaries with a mental dis , a comorbid substance use diagnosis is a

major predictor of readmissions.11–14

Medicaid patients and providers have identified inadequate planning and unsuccessful

follow-up care as root causes of high readmission rates.10,15 For individuals with a substance

use dis , prompt receipt of follow-up treatment services or medication-assisted treatment

(MAT) after an inpatient hospital discharge or a detoxification stay could be expected to

reduce readmission rates. Residential, intensive outpatient and outpatient addiction treatment

services are effective in reducing substance use and its consequences.16–19 Less is known

about their impact on readmissions.

Medicaid beneficiaries with comorbid mental and substance use dis s had a reduced

likelihood of readmission in hospitals where a higher proportion of patients received

outpatient mental health treatment within 7 days after hospital discharge.12 Receiving

addiction treatment soon after discharge is associated with reduced detoxification

readmission,20,21 with stronger findings for residential than outpatient.21

This study examined whether Medicaid beneficiaries with a substance use dis diagnosis

who received targeted follow-up services (outpatient, intensive outpatient, or residential

treatment) or MAT after an index hospital inpatient stay or residential detoxification had a

lower likelihood of postdischarge behavioral health hospital or detoxification admission

within 90 days than individuals who did not receive follow-up services. Findings from this

study should be valuable as decisions are made about which services Medicaid and other

payers should cover and how to improve care for their enrollees.

METHODS

Data

Data were from four component files of the 2008 Medicaid Analytic eXtract data set:22

personal summary (PS) for beneficiary characteristics and enrollment status, inpatient (IP) for hospital services, other therapy (OT) for detoxification and follow-up services, and prescription (RX), linked by a unique beneficiary identifier by state. Although data were from 2008, the relationship between follow-up services and postdischarge behavioral health

readmissions is not expected to change over time. Analyses used de-identified data, thus

were exempt from IRB review.

Sample

The first (index) inpatient hospital admission with a substance use dis diagnosis or

residential detoxification admission, between 4/1/2008 and 9/1/2008, was included for

individuals aged 18–64 years (N=30,439). Presence of a substance use dis was

determined by an ICD-9 diagnostic code for substance abuse or dependence in any position

for an inpatient hospital admission or by a residential detoxification. All diagnoses (not just

primary) were considered because with serious co-occurring dis s, it is not always clear

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which would be designated as primary; further, stigma may lead to a decision not to put

substance use dis diagnoses as primary. If substance use dis is noted at all, it is

important given common medical complications, as well as the need for addiction treatment

services. Of the 30,439 admissions in the sample, 30.8% had a substance use dis as the

primary diagnosis.

Excluded were individuals enrolled in both Medicaid and Medicare or enrolled in managed

care plans (because of likely incomplete claims data). Also excluded were individuals not

continuously enrolled in Medicaid 90 days before and after their index admission, and who

only had substance use dis diagnoses of nicotine/tobacco use dis , marijuana abuse,

or hallucinogen abuse.

Data were included from 10 states based on a minimum number of index admissions and

prevalence of follow-up services or MAT: Connecticut, Illinois, Indiana, Minnesota,

Missouri, North Carolina, New York, West Virginia, Wisconsin and Vermont. Thirty-seven

states were excluded that had fewer than 650 index admissions, indicating no or few fee-for-

service claims; 3 states were excluded in which none of the follow-up services were received

by at least 5% of index admissions. In the 10 states that remained, an average of 82%

Medicaid enrollees were excluded due to their dual Medicaid/Medicare eligibility or

participation in managed care plans23 (see Appendix for details by state).

Variables

The outcome was time to a behavioral health admission in the 90 days following discharge

from the index admission. For all follow-up services, eligible diagnoses were broadened to

include both substance use and mental dis s, given overlap in clinical needs and

treatment approaches. A postdischarge behavioral health admission was thus defined as an

inpatient admission with a primary diagnosis of a substance use or mental dis or a

residential detoxification admission. For readmission, only primary diagnosis was used, to

emphasize a behavioral health admission and better indicate the effect of follow-up services

on the substance use dis itself.

Four key independent variables were created, each within 14 days of discharge from the

index admission; a 14-day period indicates good clinical care by minimizing time outside of

treatment.21 Current Procedural Terminology (CPT) and Healthcare Common Procedure

Coding System (HCPCS) codes, place of service, and primary substance use or mental

dis diagnosis were used to identify residential behavioral health treatment (RES),

excluding detoxification; partial hospital or intensive outpatient program (IOP); outpatient

behavioral health services (OP); and MAT, defined as a prescription fill of buprenorphine,

disulfiram, acamprosate, or naltrexone or a HCPCS service code for methadone,

buprenorphine, or naltrexone.

The number of days to the first follow-up service received within 14-days postdischarge was

calculated. Service receipt could begin on the day of discharge (day 0). Because follow-up

services could occur at any point in the 14-day window, the opportunity to observe a

postdischarge behavioral health readmission varied. To address this, each follow-up service

was coded as a series of time-varying independent variables from day 0 to day 14 for the

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survival analysis models. Once a follow-up service was received, the remainder of the 14

days was coded as having received that service. For the few who received 2 or 3 follow-up

service types (excluding MAT), an episode approach coded only the most intensive service

(RES then IOP then OP), starting on the first day of any services received.

Covariates were basis of Medicaid eligibility (disability vs. other), demographics (age, sex,

race/ethnicity), mental or physical comorbidities at index admission, type of substance use

dis (alcohol only, any opioid use dis ), index admission length of stay (days), and

use of behavioral health services or MAT in the 90 days prior to index admission.

Analyses

Available follow-up services varied by state, depending on Medicaid coverage in that state.

Three models were run to account for each pattern of services: Model 1 – OP and MAT in all

10 states; Model 2 – OP, MAT and IOP in Indiana, Missouri, Connecticut, Vermont, and

Minnesota only; and Model 3 – OP, MAT, IOP and RES in Connecticut, Vermont, and

Minnesota only. Index admission was the unit of analysis.

Cox proportional hazards regression models were used to estimate the effect of follow-up

services and MAT on time to a behavioral health admission after discharge, with censoring

at 90 days. Hazard ratios (HRs) are interpreted similarly to odds ratios, showing at any point

in time in the 90 days after discharge whether an individual receiving the follow-up service

within 14 days was more (HR >1) or less (HR < 1) likely to have a behavioral health

admission than an individual not receiving the service within 14 days. Models included all

covariates. State was included as a fixed effect, to account for differences in population,

Medicaid eligibility, other Medicaid covered services, and other unobserved variations.

Analyses were conducted in SAS v9.3.

RESULTS

Characteristics of Sample and Index Admissions

Table 1 describes the sample and highlights the often-wide variations across states as

indicated by the minimum and maximum percentages by state (see Appendix for by-state

findings). Comorbid mental dis s were prevalent in about half of admissions and

physical comorbidities in about two-thirds. Medicaid eligibility was usually due to a

disability (66.6%) overall, but this varied widely across states (24.5% to 97.5%). A

substantial minority of index admissions (21.1%) had only an alcohol use dis coded

without any drug use dis , and 27.3% had an opioid use dis coded, regardless of

other substance use dis diagnoses. Behavioral health service use 90 days prior to the

index admission was fairly uncommon for MAT (5.1%) and inpatient (13.1%); however,

over a quarter used outpatient in that time period. The mean index admission length of stay

was 6.0 days (not shown).

Follow-up Services Within 14 Days of Discharge

Three-quarters of individuals with an index admission had no RES, IOP or OP service in the

14 days postdischarge (Table 2), but this varied by state (49.9% to 83.4%). Few individuals

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received postdischarge RES (8.3%) or IOP services (5.5%) in the states that offered them;

OP services were received by 22.8% of individuals and MAT by 10.4%. The proportions

receiving specific services also ranged across states. When including receipt of MAT, two

thirds of individuals with an index admission did not have either a follow-up service or MAT

within the 14-day window. See Appendix for by-state findings.

Of those who received a service, it most frequently started on the day of discharge or the two

days following, with frequency of first service use declining each day thereafter. Figure 1

illustrates the time to first behavioral health follow-up service, overall (dotted line) and by

state. The most variation by state occurs in the first 2 days postdischarge.

Inpatient Readmissions Within 90 Days of Discharge

Hospital readmissions for any cause were common (48.3%) in the 90-day postdischarge

period (Table 2) as were readmission rates when considering only readmissions with a

primary behavioral health diagnosis (29.3%). Postdischarge readmissions occurred

throughout the 90-day period, though were most likely within the first week postdischarge.

As shown in Figure 2, in several states a substantial proportion of individuals had behavioral

health readmissions within the first 7 days, whereas in other states behavioral health

readmissions occurred more evenly throughout the time period studied. About 70% of

individuals overall had no behavioral health readmission in the 90 days postdischarge.

Hazard of Behavioral Health Admission Within 90 Days of Discharge

Table 3 reports the hazard of a behavioral health admission within 90 days of discharge.

Model 1 includes all 10 states and only OP and MAT services. OP receipt in the 14 days

postdischarge is associated with a higher hazard of readmission in the 90 days postdischarge

(HR=1.40, p<.001). MAT is associated with a lower hazard of readmission (HR=.61, p<.

001). As expected, states were significant predictors of a behavioral health admission 90

days postdischarge. Most covariates were significant, with the exception of Medicaid

eligibility and race/ethnicity is Hispanic, other or unknown.

Model 2 adds IOP, covered only by 5 states. OP and MAT services remain significant as in

Model 1, but IOP is not a significant predictor of behavioral health admission in the 90 days

postdischarge. State and covariate effects were similar to Model 1.

Model 3 includes all four services (OP, MAT, IOP, RES), covered only by 3 states. OP and

MAT services remain significant as in Models 1 and 2. IOP is significantly related to higher

risk of readmission (HR=1.45, p<.05). RES is significantly related to lower risk of

readmission (HR=.50, p<.001). As before, most covariates are significant.

To determine if the patterns held when the included states were constant across models,

sensitivity analyses examined Models 1 and 2 using only the same 3 states as in Model 3.

With fewer states, IOP was significantly associated with higher risk or readmission in Model

2 as well as Model 3 (not shown).

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DISCUSSION

This analysis found strong support for the value of rapid follow-up with MAT or residential

treatment services to reduce risk of a behavioral health admission in the 90 days

postdischarge from an index admission. These results are consistent with studies showing an

association between MAT and residential services and improved outcomes.16,18,19 Most

behavioral health admissions, however, had no follow-up service in the 14 days

postdischarge.

Surprisingly, outpatient treatment services (and in one model, intensive outpatient) were

associated with an increased risk of readmission. On the surface this seems contradictory to

expectations, but possible explanations arise. Patients’ discharge plans may refer to an

inappropriate level of care – that is, outpatient treatment may be insufficient to meet

addiction needs yet residential treatment might not be recommended by the discharge team,

readily available, or covered under Medicaid. Studies have shown that poor treatment

matching leads to poorer substance use outcomes,24–26 thus readmission is more likely.

These findings suggest that no outpatient care is better than outpatient care (controlling for

other services). Perhaps presence of a referral to follow-up care or return to pre-existing

treatment for substance use or mental dis s indicates a greater need for services

following discharge. Further, with residential services sometimes scarce, people who would

have been appropriate for residential might go to outpatient or IOP in to receive any

care. This study could not test these scenarios; claims data do not include nuanced measures

of severity or needed level of care.

The concept of follow-up services following discharge has clear face validity, but it may be

difficult to show the benefit empirically. Challenges discussed below include access to

postdischarge services, range in quality and coordination of inpatient and postdischarge

services, and data concerns.

First, difficulties accessing behavioral health treatment arise for a variety of reasons.27

Geographic and financial barriers are common, especially for more intensive levels of care.

Fourteen days may be insufficient if individuals who are referred to care and intend to use it

are unable to obtain appointments within this short window.28,29 Medicaid clients had a 16–

22% increase in likelihood of follow-up treatment in a licensed mental health clinic when 30

days were allowed rather than 7 days postdischarge from a mental hospitalization.30

However, a longer follow-up window also allows more time in which relapse might happen.

Second, quality and coordination of postdischarge treatment may vary widely. For example,

inpatient providers in one state, prior to a Medicaid quality improvement effort, had low

rates of communication with outpatient providers, arranging for follow-up behavioral health

care, and referring individuals for physical health care.30 Claims data cannot capture

whether communication occurs between inpatient and postdischarge clinicians, level of

attention paid to substance use dis s during the inpatient stay, or whether the substance

use dis was addressed adequately or at all. If the major reason for hospitalization was a

general medical condition, addiction may have been a side issue. Postdischarge services

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might not mitigate an initial lack of attention or adequate attention to the individual’s

substance use issues.

Third, the necessary omission of states with managed care, which likely carved out

behavioral health services resulting in omitted data, means that the states analyzed may not

be representative. Replication that includes managed care and carve-out data would give

fuller confidence in these findings. Yet, there might be reasons that managed care

organizations would have different service arrays and procedures for preventing

readmissions than the relatively unmanaged fee-for-service population, which might lead to

different patterns of findings. In addition, although the states in this study had the strongest

data, few beneficiaries received any follow-up services. Individuals may have received

services in settings that have block grant funding or larger residential treatment programs

that were ineligible for Medicaid payment based on the IMD exclusion,31 thus are not in

Medicaid claims. Even if a state offers a service, it may limit which enrollees may access it

(e.g., pregnant women or people with serious mental illness).32 The relatively few

individuals meeting inclusion criteria may also reflect under-identification of people with

substance use dis s within claims data.33

Medicaid is an increasingly larger payer of behavioral health services,34 particularly under

health care reform.31 However, states vary by Medicaid eligibility, behavioral health services

covered, spending on behavioral health services,31,35,36 and contracting with specialty

managed care organizations for behavioral health benefits. A true national study would have

been ideal, but the vast variability amongst states in services available and financing

approaches made this prohibitive.

Successful recovery from any diagnosis depends on many factors: quality of care in the

index admission, overall health status, demographics, ability to purchase medications, etc.

Similarly, a complex variety of factors are associated with readmissions.37 Systematic

reviews of interventions to reduce 30-day medical rehospitalization report that no single

intervention was regularly associated with reduced risk38 and effective interventions are

complex and seek to enhance patient capacity to reliably access and enact postdischarge

care.39 A recent project reduced 30-day readmission rates and increased MAT for patients

admitted for alcohol dependence by implementing a discharge planning protocol.40

These analyses relied on Medicaid claims data. One cannot tell, for instance, if referrals

were made at the time of discharge, or if an individual had difficulties accessing services

postdischarge. Individuals dually eligible for Medicaid and Medicare were excluded, which

may omit some individuals with severe mental illness. Some services or populations are

excluded by states, thus resource availability may play a role in these findings. Services

could be obtained with other funding such as block grants, so follow-up service receipt may

be underestimated. Findings apply to those who sought Medicaid-funded care. We

controlled for disability as the basis of admission, but the definition of disability varies

across states. The original admission allowed a behavioral health diagnosis in any position,

but the readmissions variable required a primary diagnosis. This omitted some readmissions,

but allowed a focus on the impact of behavioral health services on a clearly defined

behavioral health readmission. However, this may lead to an underestimate of readmissions

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that are ultimately related to behavioral health, as this is often not the primary diagnosis but

may still be a key factor in an admission. This analysis did not examine the number of

services or other aspects of the follow-up care episode, if received.

The generalizability of these findings may be limited. The exclusion criteria reduced the

analytic sample to only 10 states. Further, in those 10 states, due to omission of enrollees

who were dually eligible for Medicaid and Medicare and those in managed care plans, on

average only 18% of Medicaid enrollees were represented in the data. The findings thus are

most applicable to people who are in fee-for-service or other plans that have low use of

treatment management approaches, or conversely, low use of additional supports to reduce

readmissions. As a Medicaid sample, the findings are likely most applicable to people who

are low-income or otherwise Medicaid-eligible.

Future research could use alternative methods to delve into open questions raised by these

limitations and discussed above as challenges. In particular, research is needed to confirm,

and if confirmed, disentangle the perplexing outpatient finding. The discussion above

suggests potential pathways to understanding the results, but careful study would be

necessary to thoroughly analyze the relationship. Further, it would be important to expand

the populations for whom these findings hold, by testing the hypotheses in Medicaid

managed care populations, where data are available, as well as privately insured populations.

CONCLUSIONS

In a time of change in the health care system, the question of how to reduce readmissions is

potent. A high proportion of patients readmitted to hospitals within a short time frame may

indicate inadequate quality of hospital care or lack of appropriate coordination of

postdischarge care. Under the ACA, financial penalties have been established for hospitals

with excessive Medicare readmissions within 30 days after acute care hospitalizations for

several diagnoses.1,41 Other payers likely will follow suit. However, concerns have risen

about holding hospitals accountable when they cannot exert control over patient behavior

and provider performance after acute care.

It is important to continue to delve into readmissions and follow-up after treatment, given

the heightened understanding of how substance use and mental dis s affect health and

recovery, the likelihood of readmission, and the high stakes related to health care in this

population. Future research should further investigate how MAT and residential treatment

may be useful in improving outcomes after an inpatient stay and the counterintuitive

outpatient results.

These findings highlight several policy implications. Most individuals had no follow-up

services within the 14-day window; if services are not received, they cannot improve

outcomes. Policies implemented after the time period of these admissions, including the

ACA and federal parity, should increase access to behavioral health services under

Medicaid. Further, Medicaid programs should be encouraged to ensure that a range of

substance use dis treatment benefits are offered to all Medicaid beneficiaries. This may

require a renewed focus on how to best allocate scarce resources, especially for more

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expensive services such as residential treatment. States should ensure that barriers to use of

MAT are reduced, for example by omitting prior authorization requirements, or by

developing models such as hub-and-spoke to increase access to MAT in the community, or

by specifically encouraging training for and adoption of MAT among Medicaid providers.

Efforts are needed such as focused discharge planning, follow-up phone calls, coordination

with primary care providers, use of performance measures (e.g., follow-up after

hospitalization for mental illness42), and better linkages between hospitals and specialty

addiction treatment providers. Solutions that focus on benefit design should be combined

with efforts targeted at referral processes to ensure that more individuals who are discharged

from inpatient treatment receive appropriate and timely follow-up services.

Supplementary Material

Refer to Web version on PubMed Central for supplementary material.

References

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