Variations in Health Care Utilization Patterns Among Inflammatory Bowel Disease Patients at Risk for High Medical Service Utilization Enrolled in High Deductible Health Plans

Abstract

Background

High-deductible health plans (HDHPs) are increasing in prevalence as a cost control device for slowing health care cost growth by reducing nonessential medical service utilization. High cost-sharing associated with HDHPs can lead to significant financial distress and worse disease outcomes. We hypothesize that chronic disease patients are delaying or foregoing necessary medical care due to health care costs.

Methods

A retrospective cohort analysis of IBD patients at risk for high medical service utilization with continuous enrollment in either an HDHP or THP from 2009 to 2016 were identified using the MarketScan database. Health care costs were compared between insurance plan groups by Kruskal-Wallis test. Temporal trends in office visits, colonoscopies, emergency department (ED) visits, and hospitalizations were evaluated using additive decomposition time series analysis.

Results

Of 605,862 patients with a diagnosis of IBD, we identified 13,052 eligible patients. Annual out-of-pocket costs were higher in the HDHP group (n = 524) than the THP group (n = 12,458) ($2870 vs $1,864; P < 0.001) without any difference in total health care expenses ($23,029 vs $23,794; P = 0.583). Enrollment in an HDHP influenced colonoscopy, ED visit, and hospitalization utilization timing. Colonoscopies peaked in the fourth quarter, ED visits peaked in the first quarter, and hospitalizations peaked in the third and fourth quarter.

Conclusions

High-deductible health plan enrollment does not change the cost of care; however, it shifts health care costs onto patients and changes the timing of the care they receive. High-deductible health plans are incentivizing delays in obtaining health care with a potential to cause worse disease outcomes and financial distress. Further evaluation is warranted.

INTRODUCTION

Enrollment in high-deductible health plans (HDHPs) has rapidly expanded over the last decade in alignment with the concept of reverse moral hazard. The theory of reverse moral hazard hypothesizes that higher cost-sharing among high-deductible health plan enrollees should mitigate excessive utilization and cost of health care in the United States.¹ In 2017, 43.4% of nonelderly adults with employment-based coverage were enrolled in an HDHP, and it is anticipated that this percentage will continue to rise.² Recent evaluations of the reality of HDHPs have demonstrated that high cost-sharing can lead to significant financial distress^{3, 4} and delays or avoidance in necessary medical care due to cost.^5–9 The financial burden associated with high cost-sharing is of particular concern for people with chronic conditions who have little choice in seeking needed medical care. For these patients, their disease may lead to lost wages, debt, reduced quality of life, and overall worse mental and physical disease outcomes.^10–12 Currently, our understanding of the impact of HDHPs on health care utilization and costs among patients with chronic diseases remains limited.

Inflammatory bowel disease (IBD) is a chronic gastrointestinal condition associated with high medical expenditures related to the need for ongoing disease monitoring and hospitalizations, expensive medications, and endoscopic and surgical procedures.^{13, 14} Inflammatory bowel disease disproportionately affects vulnerable individuals who are susceptible to health care–related financial distress, especially when patients are diagnosed as young adults and have not had the opportunity to accumulate a financial reserve to withstand financial disruptions.¹⁵ If patients are not financially prepared, out-of-pocket costs can lead to substantial hardship. These unique features make IBD an important chronic disease model to evaluate the effects of out-of-pocket costs on medical service delays and avoidance.

While, the high direct health care costs associated with IBD care are well established, very few studies have evaluated the impact of cost-sharing on patients with chronic high expenditure conditions such as IBD.^{14, 16, 17} We aimed to quantify the out-of-pocket health care costs for IBD patients at risk for high medical service utilization and to examine variations in health care service utilization throughout the year among HDHP and traditional health plan (THP; ie, private health insurance plans without a high deductible) enrollees. We hypothesized that IBD patients enrolled in HDHPs would have more variations in health care service utilization throughout the year than THP enrollees, which would suggest that patients and/or physicians may be modifying health care utilization behaviors due to higher patient cost-sharing.

MATERIALS AND METHODS

Study Design and Data Source

We performed a retrospective cohort analysis using a large nationwide insurance claims database to quantify out-of-pocket spending and identify variations in utilization patterns throughout the year. Data were obtained from Truven Health MarketScan Commercial, Claims, and Encounters and Medicare Supplemental databases (Truven Health Analytics [now IBM Watson, Cambridge, MA]). The MarketScan databases contain health insurance claims for more than 230 million privately insured patients in the United States; however, they do not include patients insured by Medicaid. Medicare-eligible retirees with employer-sponsored Medicare were included. MarketScan has previously been used to evaluate health outcomes and cost parameters in various clinical settings including IBD.^17–19 We examined outpatient visits, inpatient admissions, services, enrollment tables, and pharmacy claims for IBD patients from January 1, 2009, to December 31, 2015. De-identified patient-level data were obtained through a license agreement with approval from the institutional review board (HUM00127665).

Study Population

The International Classification of Diseases (ICD), Ninth Revision, Clinical Modification (CM) diagnosis codes were used to identify patients 18 years or older with a diagnosis of Crohn’s disease (CD; ICD-9-CM 555.x) and ulcerative colitis (UC; ICD-9-CM 556.x) and were required to have at least 3 IBD codes on 3 different visit encounters or 1 IBD‐related visit encounter associated with an IBD medication prescription (a 5‐aminosalicylate, immunomodulator, or biologic).^{20, 21} Inflammatory bowel disease patients were defined as at risk for high medical service utilization according to a modified version of the previously published Michigan IBD Risk Model.²² The Michigan IBD Risk Model uses 5 factors to identify IBD patients at high risk for hospitalization, emergency department (ED) visits, and high treatment charges in the upcoming year.²² Recent IBD flare plus periflare narcotic was used to identify IBD patients at risk for high medical service utilization. An IBD flare was defined as a new prescription for an oral systemic corticosteroid for at least 14 days not preceded by oral corticosteroid use within 120 days; this is consistent with previously published literature.²³ Inclusion criteria required at least 12 months of continuous insurance enrollment before and after the index flare to accurately capture health comorbidities and utilization events. Patients without an insurance plan listed and patients who switched between a HDHP and a THP during the 7-year study period were excluded to avoid contamination between study groups.

Study Variables

We abstracted age at first enrollment, gender, region, and IBD type. We extracted Charlson comorbidities, anxiety, and depression over the year before the index flare according to an established algorithm.²⁴ Biologic utilization was defined as any prescription claim of either adalimumab, infliximab, certolizumab, vedolizumab, or ustekinumab during the study period. Insurance plan type was defined according to MarketScan; HDHP was defined as a consumer-driven health plan in addition to the stringent MarketScan definition for a high-deductible health plan, which was coupled with a health service account. All other insurance plans were categorized as a traditional health plan (Supplement Table 1). The 1-year insurance plan period was divided into 4 quarters starting in January, each quarter consisting of a 3-month period. Annual direct costs were calculated as a sum costs of all claim encounters (inpatient, outpatient, and pharmacy claims) of an individual and then divided by their enrollment time, which was calculated based on the elapsed time between their first and their last recorded claim. Out-of-pocket costs were calculated as a sum of coinsurance, copay, and deductible.¹⁷ Total health care expenses are provided as gross payment to hospital and/or provider and consist of a combination of out-of-pocket costs and insurer/employer-incurred costs.¹⁷

Statistical Analysis

Univariable comparisons were performed using the χ ² test and test of equal proportions for categorical variables and the Kruskal-Wallis test for nonparametric continuous variables. Temporal trends in office visits, colonoscopies, ED visits, and hospitalization were assessed. We compared the average yearly proportion of each particular event occurring in a quarter as a function of all the individuals who were enrolled in a particular health plan during that year; therefore, the sum of the quarters will be >1 if an event occurred for subject in multiple quarters in a single year. Only events occurring in the first calendar year after enrollment were included to avoid misrepresentation from mid-year enrollment (eg, for a patient with a first encounter of 01-26-2013 or 12-26-2013, the start date of analysis was defined as 01-01-2014). Insurance period time trends were evaluated using an additive decomposition time series analysis, in which the overall time trend was separated into 3 individual components (a trend-cycle component, a seasonal component, and a residual component) and deconstructed and estimated using their relative contribution to the overall trend assuming an additive decomposition.^{25, 26} All analyses were performed using R version 3.5.2 (R Foundation for Statistical Computing, Vienna, Austria).

RESULTS

Patient Characteristics

The study cohort evaluated 605,862 IBD patients between 2009 and 2016, of which 89,190 (14.7%) were considered at risk for high medical service utilization. The final cohort included 13,052 patients (12,458 with a THP and 594 with an HDHP) based on inclusion criteria (Fig. 1). Patient characteristics according to deductible status are presented in Table 1. Patients enrolled in a THP had a higher age at enrollment (46.0 years vs 40.0 years; P < 0.001), longer enrolled period (4.45 years vs 3.88 years; P < 0.001), and higher rates of comorbidities including cerebrovascular disease (9.7% vs 4.5%; P < 0.001), congestive heart failure (7.0% vs 3.0%; P < 0.001), chronic obstructive pulmonary disease (28.4% vs 22.6%; P = 0.002), diabetes mellitus (19.5% vs 11.1%; P < 0.001), and chronic renal disease (7.0% vs 3.5%; P = 0.001).

FIGURE 1.

Patient cohort inclusion/exclusion criteria.

TABLE 1.

Patient Characteristics

	Traditional Health Plan (N = 12458)	High Deductible Health Plan (N = 594)	P
Age at Enrollment, Median (Q1, Q3)	46.0 (33.0, 57.0)	40.0 (30.0, 50.0)	< 0.001
Female, number (%)	7441 (59.7%)	346 (58.2%)	0.468
Region, number (%)			< 0.001
Northeast	2011 (16.1%)	81 (13.6%)
North Central	3109 (25.0%)	175 (29.5%)
South	4907 (39.4%)	247 (41.6%)
West	2236 (18.0%)	91 (15.3%)
IBD Diagnosis, number (%)			0.944
Crohn’s Disease	8456 (67.9%)	404 (68.0%)
Ulcerative Colitis	4002 (32.1%)	190 (32.0%)
Enrollment Period, mean (SD)	4.45 (1.82)	3.88 (1.85)	< 0.001
Biologic Medication, number (%)	2424 (19.5%)	134 (22.6%)	0.063
Comorbidities, number (%)
Cancer	513 (12.1%)	61 (10.3%)	0.170
Cancer with metastasis	97 (4.0%)	19 (3.2%)	0.334
Cerebrovascular Disease	1213 (9.7%)	27 (4.5%)	< 0.001
Congestive Heart Failure	876 (7.0%)	18 (3.0%)	< 0.001
Chronic Obstructive Pulmonary Disease	3534 (28.4%)	134 (22.6%)	0.002
Diabetes Mellitus	2429(19.5%)	66 (11.1%)	< 0.001
Renal Disease	869 (7.0%)	21 (3.5%)	0.001
Depression	2464 (19.8%)	115 (19.4%)	0.803
Anxiety	3230 (25.9%)	143 (24.1%)	0.314

Annual Cost Burden

Individual cost-sharing metrics, including coinsurance, deductible, and total out-of-pocket-costs, were higher in the HDHP group compared with the THP group (Fig. 2; Supplemental Table 2). Patients with an HDHP paid a median annual coinsurance of $876 (vs $524; P < 0.001), median annual deductible of $1483 (vs $302; P < 0.001), and median annual out-of-pocket cost of $2870 (vs $1864; P < 0.001) as compared with those with a THP. Conversely, the median annual copay was $102 in the HDHP group compared with $742 in the THP group (P < 0.001). Despite variable degrees of cost-sharing intended to reduce total health care costs, the median annual total health care expenses were similar in both groups (HDHP $23,029 vs THP $23,794; P = 0.628).

FIGURE 2.

Median annual cost burden per patient according to deductible status. Financial data are calculated as a median for all health plan type enrollees; therefore, out-of-pocket costs will not be the sum of coinsurance, copay, and deductible. Health care expenses consist of out-of-pocket costs in addition to all facility and provider fees paid by the insurance company or employer.

Temporal Trends in Health Care Utilization

Insurance plan type differentially influences timing of health care service utilization in IBD patients at risk for high medical service utilization. Figure 3A illustrates an increase in office visit utilization over the 7-year study period in the THP group compared with the HDHP group. In addition, there is a clear and persistent variation throughout the year in IBD patients enrolled in THPs, in which office visit utilization is the highest in the first quarter and lowest in the fourth quarter compared with IBD patients enrolled HDHP who appear to utilize office visits consistently throughout the year. Figure 3B illustrates an increase in colonoscopy utilization over time in the HDHP group compared with the THP group. In addition, there is a clear and persistent variation throughout the year in IBD patients enrolled in HDHPs, in which colonoscopy utilization is the highest in the fourth quarter compared with IBD patients enrolled in THPs who utilize colonoscopy consistently throughout the year. Figure 3C illustrated persistently elevated ED visits in the THP group relative to the HDHP group and an increase in ED visits over the study period in THP group, whereas the HDHP group saw a slight decrease in ED visits over the study period. In addition, there is a clear and persistent variation throughout the year in IBD patients enrolled in HDHPs in which ED visits are the highest in the first quarter compared with THP enrollees who utilize ED visits consistently throughout the year. Figure 3D illustrates a clear and persistent variation throughout the year in hospitalizations in IBD patients enrolled in HDHPs, in which hospitalizations are highest in the third and fourth quarter and lowest in the first and second quarter compared with IBD patients enrolled THP who have consistent hospitalizations throughout the year.

FIGURE 3.

Utilization patters according to time. A) Utilization of office visits according to time. B) Utilization of colonoscopy according to time. C) utilization of emergency room visits according to time. D) Utilization of hospitalization according to time. Each utilization outcome was evaluated by decomposition time series analysis which reduces a time series into 3 components: trend over time, seasonal effects, and random errors. Each utilization outcome is divided into 4 panels (top to bottom). Panel 1 represents the overall time trend which includes all 3 components of the decomposition model. Panel 2 represents the year-to-year time trend over time from 2010 to 2015. Panel 3 represents the trend over the course of an insurance period (1 year from January to January). Panel 4 represents the random error or residual noise after the 2 models above are subtracted from the overall trend.

DISCUSSION

Our study demonstrates that among IBD patients at risk for high medical service utilization, the median annual out-of-pocket costs are higher in IBD patients enrolled in HDHPs compared with those enrolled in THPs without any difference in the median annual total health care expenses. This suggests that HDHP enrollment is shifting health care costs onto patients without reducing the overall costs of their health care. In addition, variations throughout the year in utilization of colonoscopy, ED visits, and hospitalization were observed and are more prominent in the HDHP group compared with the THP group. Our results suggest that HDHP enrollment is shifting the timing of care and is likely incentivizing delays in care with a potential for worse disease outcomes and financial distress in a vulnerable group of chronic disease patients. Moreover, this observation calls the utility of reverse moral hazard in question for high risk patients with chronic diseases.

Inflammatory bowel disease is unusual as a chronic disease, as it frequently affects patients in their late teens and early 20s when most people make critical decisions about their education and career goals.¹⁵ One would expect the resultant financial distress of high cost-sharing to be more pronounced in IBD patients compared with patients with other chronic diseases, as most chronic conditions develop later in life, allowing patients more productive years in the workforce and the opportunity to develop a financial reserve.^27–29

Our estimates of total direct health care costs and total out-of-pocket costs approximate previously published estimates.^{14, 16, 30–32} High-deductible health plan enrollment among chronic diseases at risk for high medical service utilization did not reduce overall health care expenses, which may be largely unavoidable in these patients. Rather, HDHPs shifted these costs to these vulnerable patients, suggesting that the primary beneficiary of HDHP enrollment is the employer and the health insurers rather than the patient. It is unlikely that lower premiums associated with HDHPs offset the higher out-of-pocket costs for these chronic disease patients. This observation challenges the effectiveness of cost-sharing as a cost control device for patients with IBD at risk for high medical service utilization—and potentially for all patients with chronic diseases. Both patient quality of life and financial stability are negatively affected by these high out-of-pocket costs.³³ As the number of people enrolled in HDHPs continues to increase, this trend could place considerable strain on young and otherwise healthy patients living with a chronic disease such as IBD.³⁴

In addition to the disproportionate out-of-pocket costs incurred by HDHP enrollees, our data demonstrate a clear temporal trend in health care utilization throughout the year. The HDHP group specifically utilized colonoscopy and hospitalizations more in the fourth quarter and emergency services more commonly in the first quarter, despite relatively consistent use throughout the year among THP enrollees. Conversely, THP enrollees utilized office visits more commonly during the first quarter, while office visit use among HDHP enrollees was more consistent throughout year. Together, these findings suggest that insurance type influences the timing of health care utilization among IBD patients at risk for high medical utilization.

The temporal trend relating the use of colonoscopy to insurance period may suggest that patients with high deductibles are deferring colonoscopy until after their deductible is met. Alternatively, the fourth quarter peak in colonoscopy utilization may reflect more active disease during this time due to a cumulative effect of delayed and missed IBD-related health care services throughout the year, necessitating urgent colonoscopic utilization to assess disease activity and guide therapeutic decisions. Our study shows that colonoscopy utilization overall is increasing in patients enrolled in HDHPs in comparison with those enrolled in THPs, which is apparently driven by increased fourth quarter use of colonoscopy.

The temporal trend relating ED use among high risk IBD patients with HDHPs is more difficult to explain and warrants further investigation. This may be due to patients deferring routing outpatient care early in the year to avoid out-of-pocket costs, leading to earlier need for emergent care. Alternatively, HDHP enrollees may be utilizing more emergent care early in the year as they have no incentive to utilize less expensive office visits over emergency care before meeting their deductible, as they will have higher out-of-pocket costs regardless of which service they use. This deferral of preventative care is likely also contributing to higher rates of hospitalization in the second half of the insurance period. Without qualitative evaluation, it is impossible to discern if physician behaviors change according to patient insurance type and if these are playing a meaningful role in medical service recommendations.

The strengths of this study include the use of a previously validated, large, nationwide insurance claims database to examine the effects of cost-sharing in IBD patients at risk for high medical service utilization. The restriction of our study cohort to IBD patients at risk for high medical service utilization allows us to evaluate the effects of high deductibles on a patient population likely to utilize the health care system and be affected by high cost-sharing.

Study limitations include the generalizability of IBD to all chronic diseases, especially those with stable disease and minimal interactions with the health care system. However, one could argue that since high risk, high utilization patients have the largest economic impact on the health care system, they should be the focus of future investigation and intervention. Granular levels of detail relating to IBD-specific characteristics (such as phenotype, extent, location, severity, disease duration, and prior medication use) are not accurately recorded in an administrative database. In addition, databases are subject to data entry errors which may lead to inaccurate billing codes. Though our data allowed us to distinguish between HDHPs and THPs, we were not able to determine the actual deductible amount for each patient enrolled. In addition, our study design was subject to several real-world selection biases on both an employer level and individual member level. Unfortunately, our current data does not allow us to discern between mandatory employer-mediated HDHP enrollment and optional HDHP enrollment. There are likely unobserved factors affecting both plan selection and health care utilization among the plan members in our study. Lastly, our study also does not consider the significant indirect costs that impose additional burden on patients with IBD.

In conclusion, this study provides a comprehensive assessment of the annual out-of-pocket costs by plan type and evaluates the effect of plan type on timing of health care service utilization throughout the year in IBD patients at risk for high medical service utilization. Our study demonstrates that high levels of cost-sharing may play an important role in temporal variations in health care utilization in these high risk chronic disease patients. This temporal trend suggests that IBD patients at risk for high medical service utilization enrolled in HDHPs are shifting the timing of care and may be incentivizing delays in care with a potential for worse disease outcomes and financial distress in a vulnerable group of chronic disease patients. Recognizing that these patterns exist and recognizing their impact are the first steps to addressing this important issue. Further research is needed to better understand the intricacies of this variation and develop health system and policy solutions to ameliorate its impact on disease-specific outcomes for high risk chronic patients who are burdened by high cost-sharing.

Glossary

Abbreviations

CD

Crohn’s disease

HDHPs

high-deductible health plans

IBD

inflammatory bowel disease

ICD

International Classification of Diseases

THP

traditional health plan

UC

ulcerative colitis

Conflicts of Interest: PDRH has received consulting fees from AbbVie, Amgen, Genentech, JBR Pharma, and Lycera. JK has received consulting fees from SeeChange Health, HealthMine, and the Kaiser Permanente Washington Health Research Institute; and honoraria from the Robert Wood Johnson Foundation, AbilTo, Inc., the Kansas City Area Life Sciences Institute, and the American Diabetes Association. JK and AKW receive support from the Department of Veterans Affairs, Veterans Health Administration, Health Services Research and Development Service. JK and AKW are VA HSR&D Career Development awardees at the Ann Arbor VA. The views expressed in this article are those of the authors and do not necessarily reflect the position or policy of the Department of Veterans Affairs or the United States government. All other authors report no disclosures.