Incremental Health Care Expenditure of Chronic Cutaneous Ulcers in the United States

Key Points

Question  What is the incremental financial burden posed by chronic cutaneous ulcers?

Findings  In this analysis of data from the Medical Expenditure Panel Survey for 288 698 patients, controlling for comorbidities and sociodemographic covariates, chronic cutaneous ulcers were associated with a 1.73-fold ($7582.00) incremental increase in annual health care expenditure. Expenses for patients with chronic cutaneous ulcers are increasing, particularly outpatient cost of care and prescription medication expenditure.

Meaning  Chronic cutaneous ulcers pose a substantial US financial burden, and investigating their associated health care costs is critical in identifying strategies for decreasing their outcomes on the health care system, particularly when considering their association with various chronic diseases.

Importance  Despite the increasing incidence of chronic cutaneous ulcers (CCUs), limited information exists regarding their incremental economic burden.

Objective  To provide nationally representative estimates regarding the incremental health care cost of CCUs, controlling for comorbidities and sociodemographic characteristics.

Design, Setting, and Participants  This retrospective analysis used 9 years of longitudinal data from the Medical Expenditure Panel Survey (MEPS; January 1, 2007, through December 31, 2015). Patients with CCUs were identified using Agency for Healthcare Research and Quality–produced software that included several codes from the International Classification of Disease, 9th Revision Clinical Modification, for chronic ulcers of the skin. A cross-validated 2-part generalized linear model estimated the adjusted incremental expenditure for individuals with CCUs while controlling for comorbidities and sociodemographic covariates. Data were analyzed from July 1 through September 1, 2018.

Main Outcomes and Measures  Incremental cost of CCUs, total cost of care, and expenditures associated with inpatient care, outpatient care, prescription medications, emergency department visits, and home health care.

Results  A total of 288 698 patients (52.4% female; mean [SD] age, 38.2 [22.4] years) were included, of whom 1786 had CCUs and 286 912 did not. Patients with CCUs were more likely to be female (1078 [60.4%]), non-Hispanic (1388 [77.7%]), previously or currently married (1440 [80.6%]), and covered by Medicaid/Medicare (852 [47.7%]) and had a lower income (954 [53.4%]) when compared with patients without CCUs (P < .001 for all). The mean (SD) annual cost of care per patient with CCUs was greater than 4 times that of patients without CCUs ($17 958 [$1031.90] vs $4373.20 [$48.48]). After controlling for Charlson comorbidity index and sociodemographic factors measured in MEPS, the cost of care for patients with CCUs was 1.73 times as high as that of patients without CCUs (95% CI, 1.53-1.96; P < .001), and patients with CCUs were estimated to incur $7582.00 (95% CI, $6201.47-$8800.45) more in annual health care expenditures. When accounting for the prevalence of CCUs (0.6%), CCUs were associated with more than $16.7 billion per year in population-level US health care expenditures. Among patients with CCUs, mean annual expenditures rose from the 2010-2012 to 2013-2015 periods in association with prescription medications ($3117.26 to $6169.12), outpatient care ($3568.06 to $5920.75), and home health care ($1039.54 to $1670.56).

Conclusions and Relevance  Results of this study suggest that chronic cutaneous ulcers are associated with substantial incremental increases in annual health care expenditure. Expenses for patients with CCUs are increasing, particularly with regard to outpatient cost of care and prescription medication expenditure. As health care costs rise, investigators must identify strategies to prevent and treat CCUs.

Chronic cutaneous ulcers (CCUs) are associated with a wide variety of conditions, including diabetes, arterial and venous insufficiency, and systemic inflammatory conditions.¹ An estimated 1% to 2% of adults in developed countries will have a CCU during their lifetime,² which may lead to complications such as infection, resulting in a cycle that contributes to poor outcomes.^1,2 Furthermore, the burden of CCUs continues to rise owing to the increasing burden of chronic illness, an aging population, and a rise in the incidence of diabetes and obesity.^3,4

Limited information exists regarding the economic burden posed by CCUs. The objective of this study was to provide nationally representative estimates regarding the incremental health care cost of CCUs while controlling for comorbidities and sociodemographic characteristics.

We analyzed data from the Medical Expenditure Panel Survey (MEPS) from January 1, 2007, to December 31, 2015, a nationally representative survey administered annually by the Agency for Healthcare Research and Quality (AHRQ) to assess patterns of use of outpatient health care services in the United States.⁵ Respondents are representative of the US civilian, noninstitutionalized population, and MEPS uses a stratified random sampling procedure to select participants who are then followed up for 2 years. Five questionnaires are administered to participants during follow-up using computer-assisted personal interviewing. MEPS also collects supplemental information, including visit dates, diagnosis and procedure codes, charges, and payments from health care professionals and pharmacies, by telephone. More detail on the survey structure of MEPS can be found online.⁵ Healthcare Cost and Utilization Project data sets, produced by the AHRQ, conform to the definition of a limited data set specified by the Health Insurance Portability and Accountability Act privacy rule.⁶ As such, institutional review board approval and informed consent were waived for the use of this publicly available, deidentified database.

We adjusted expenditures for several demographic, socioeconomic, and health-related factors. The age of participants was categorized as younger than 18, 18 to 34, 35 to 64, or 65 years and older. Respondent race was categorized as white, black, Asian, or other. Native American and mixed-race respondents were included in the “other” category because of their relative scarcity in MEPS, causing wide 95% CIs. Ethnicity was categorized as Hispanic or non-Hispanic. Marital status was described as never married, formerly married (divorced, separated, or widowed), or married. Individual income levels were categorized as poor (<100.0% of the 2015 federal poverty line [FPL]), near poor (100.0%-124.9% of the 2015 FPL), low (125.0%-199.9% of the 2015 FPL), middle (200.0%-399.9% of the 2015 FPL), or high (≥400% of the 2015 FPL). Educational attainment was classified as having completed high school or a General Educational Development diploma, some college, a bachelor’s degree or higher, or no degree or diploma. Insurance status was described as private, Medicare/Medicaid, or uninsured. Geographic areas of residence were categorized into Northeast, South, Midwest, and West. Additional information on how geographic region corresponds to a participant’s state of residence can be found in the MEPS documentation.⁵

The comorbid disease burden of MEPS participants was described using the Charlson comorbidity index (CCI).^7,8 The CCI was categorized into 0, 1, 2, 3, 4, and at least 5 comorbidities because a categorical treatment of this variable facilitates interpretation. In addition, including CCI as a continuous risk factor led to significant overfitting as demonstrated by a poor expected performance on test set root mean square errors (eTable in the Supplement).

To account for a potential trend in health care expenditures, the survey period was categorized into 2007 to 2009, 2010 to 2012, or 2013 to 2015. Years were categorized to avoid year-to-year fluctuations in expenditures that we expected to observe in subgroups with smaller sample sizes. Self-reported health status was measured on a 5-point scale as excellent, very good, good, fair, or poor. Patients with CCUs were identified using AHRQ-produced Clinical Classification Software code 199, consisting of several codes for chronic ulcers of the skin from the International Classification of Disease, Ninth Revision, Clinical Modification (707.0, 707.00-707.07, 707.09, 707.1, 707.10-707.15, 707.19-707.25, 707.8, and 707.9).⁹

Data were analyzed from July 1 through September 1, 2018. Sociodemographic characteristics of patients with and without CCUs were compared using Rao-Scott χ² tests, and age was compared via unpaired 2-tailed t test. Expenditures included inpatient expenses, outpatient and office-based expenses, home health services, emergency department visits, and prescription medications for all medical indications. All expenditures were adjusted for inflation to 2015 US dollars using the Bureau of Labor Statistics Consumer Price Index.¹⁰

We constructed a marginalized 2-part linear regression model to estimate the adjusted incremental expenditure for individuals with CCUs while controlling for covariates. The 2-part model is popular in the study of health care expenditures because it accounts for their zero inflation and right-skewedness.¹¹ The model was selected for this analysis because it outperformed other models for health care expenditure on this data set, including tobit and negative binomial models. Performance was measured by splitting the data into equal-sized training and test sets, fitting models to the training data, and then comparing the models’ root mean square errors on the test set. The Akaike information criteria was also compared between the models (eTable in the Supplement). The 2-part model we used includes a probit model to calculate the probability of nonzero medical expenditure, followed by a generalized linear model using a gamma distribution with a log link to provide adjusted estimates of total medical expenditures (conditional on a positive medical expenditure).¹¹ A probit model was used for the first part of the 2-part model because it outperformed a logistic regression model on test set root mean square errors (eTable 1 in the Supplement). We used a marginalized version of the 2-part model because it allows for a more intuitive and generalizable interpretation of coefficients.¹²

To account for the complex sampling of MEPS, all standard errors were estimated using the R survey package, which bases calculations on person-level weights, clustering, and stratification data.¹³ A 1-sided P < .05 was considered significant, and all statistical analysis was performed using R (version 3.5.1; R Foundation). Incremental expenditure was calculated by adjusting the actual expenditures of respondents with CCUs by the expenditure ratio estimate from the 2-part model. The 95% CI for this estimate was calculated based on the 95% CLs of the expenditure ratio. Annualized estimates derived for each 3-year block for total expenses, inpatient cost of care, prescription medication expenses, emergency department cost of care, outpatient cost of care, and home health expenditures for patients with and without CCUs were graphed using SAS software (version 9.4; SAS Institute, Inc). Differences in itemized expenditures were compared across periods using the Wilcoxon rank sum test.

Our sample included a total of 288 698 patients (52.4% female and 47.5% male; mean [SD] age, 38.2 [22.4] years), of whom 1786 had CCUs and 286 912 did not. In univariate analyses, patients with CCUs were more likely to be female (1078 [60.4%] vs 150 358 [52.4%]), non-Hispanic (1388 [77.7%] vs 201 421 [70.2%]), previously or currently married (1440 [80.6%] vs 146 535 [51.1%]), and insured by Medicaid/Medicare (852 [47.7%] vs 86 054 [30.0%]) and to have a lower income (954 [53.4%] vs 130 135 [45.4%]) compared with patients without CCUs (P < .001 for all) (Table 1). Patients with CCUs also had a greater number of comorbidities (CCI≥2, 954 [53.4%] vs 37 859 [13.2%]; P < .001) and were more than 20 years older than patients without CCUs (mean [SD] age, 56.4 [18.6] vs 35.6 [22.2]; P < .001) (Table 1).

Overall, the mean (SD) annual cost of care per patient with CCUs was greater than 4 times that of patients without CCUs ($17 958 [$1031.90] vs $4373.20 [$48.48]). After controlling for CCI and sociodemographic factors, the cost of care for patients with CCUs was 1.73 times as high as that for patients without CCUs (95% CI, 1.53-1.96; P < .001) (Table 2). Ultimately, after controlling for comorbidities and sociodemographic factors, patients with CCUs are estimated to incur $7582.00 (95% CI, $6201.47-$8800.45) more in annual health care expenditure compared with patients without CCUs. When accounting for the prevalence of CCUs found in this study (0.6%), our data suggest that CCUs were associated with more than $16.7 billion per year in population-level US health care expenditures.

The mean total cost of care for patients with CCUs rose from $16 844.11 (95% CI, $15 234.45-$18 453.77) in the 2010-2012 period to $20 554.62 (95% CI, $18 478.52-$22 630.71) in the 2013-2015 period (Figure, A). Patients with CCUs had greater annual inpatient, prescription, emergency department, outpatient, and home health expenses than those without CCUs. The decrease in mean annual inpatient cost per patient with CCUs from the 2010-2012 ($7064.54; 95% CI, $5893.07-$8236.00) to 2013-2015 ($4812.86; 95% CI. $4211.11-$5414.61) periods was not statistically significant (P = .39) (Figure, B). Mean annual expenses associated with prescription medications for patients with CCUs nearly doubled from $3117.26 (95% CI, $2850.42-$3384.09) in the 2010-2012 period to $6169.12 (95% CI, $4538.32-$7799.92) in the 2013-2015 period (P = .004) (Figure, C). Mean annual outpatient cost of care for patients with CCUs increased from $3568.06 (95% CI, $3235.10-$3901.03) in the 2010-2012 period to $5920.75 (95% CI, $3235.10-$3901.03) in the 2013-2015 period (P < .001) (Figure, D). A mean increase in home health expenditure occurred from $1039.54 (95% CI, $735.72-$1343.37) in the 2010-2012 period to $1670.56 (95% CI, $1289.58-$2051.45) in the 2013-2015 period (P = .04) (Figure, E). Mean emergency department expenses remained consistent between the 2010-2012 ($589.29; 95% CI, $497.75-$680.83) and 2013-2015 ($594.55; 95% CI, $512.98-$676.12) periods (Figure, F).

This study shows that the mean incremental annual health care expenditure associated with CCUs per patient is $7582.00 and the presence of a CCU is associated with a 1.73-fold incremental increase in annual health care expenditure when controlling for all other factors. Health care cost estimates in this study are based on patients’ overall costs and are not specifically linked to the direct costs for a CCU alone; as such, health care costs for other confounders (eg, diabetes and vascular disease) may play a role in the calculated incremental cost. The prevalence of CCUs in our data (0.6%) is lower than reported previously (1%-2%),^4,14 suggesting that the financial burden of CCUs may be even greater than we report herein.

Previous research from the US Wound Registry¹⁵ reported that the mean outpatient cost to heal per wound was $3927 in 2005, with jeopardized flaps and grafts contributing the most expensive costs ($9358). The outpatient cost of care reported in the present study was similar in the 2007-2009 ($3850.55) and 2010-2012 ($3568.05) periods but increased to $5920.75 in the 2013-2015 period. The increase in expenditures associated with prescription medications and outpatient care, alongside with a decrease in inpatient expenses in the 2013-2015 period, may reflect a shift in wound care to the outpatient setting over time.³ Efforts focused on prevention of CCU onset for patients with chronic conditions may decrease the treatment burden posed by CCUs.³ Further research is required to evaluate how increased use of outpatient wound care services can contribute to decreasing the financial burden of CCUs.

Strengths of this study include the use of a large database to provide data representative of the civilian noninstitutionalized American population.⁵ In addition, we used a cross-validated 2-part incremental expenditure model to evaluate the specific cost accompanying a CCU diagnosis. This study also has a few important limitations. Although most patient reports are verified by the AHRQ with physicians, including the associated expenditures, recall bias may have affected the responses of some patients. Furthermore, medical conditions for MEPS respondents are identified if reported as a general problem, associated with medical care events, or associated with missing school or work, which may explain the lower prevalence of CCUs in this study than previously reported.^3-5,14 In addition, we were unable to determine the specific components of each cost, including the specific prescription medications contributing to the overall cost.

Investigating health care costs due to CCUs is critical in identifying strategies for decreasing potentially adverse outcomes on the US health care system, especially when considering their association with various chronic diseases. As health care costs rise, it is vital to identify strategies to prevent and treat CCUs. Ultimately, a health care system that integrates wound healing into the standard management for chronic conditions may be helpful in curbing costs due to CCUs.⁴

Accepted for Publication: December 21, 2018.

Corresponding Author: Raghav Tripathi, MPH, Department of Dermatology, University Hospitals Cleveland Medical Center, Lakeside 3500, 11100 Euclid Ave, Cleveland, OH 44106 (raghav.tripathi@case.edu).

Published Online: March 20, 2019. doi:10.1001/jamadermatol.2018.5942

Author Contributions: Mssrs Tripathi and Knusel had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: Tripathi, Knusel, Scott.

Acquisition, analysis, or interpretation of data: Tripathi, Knusel, Ezaldein, Honaker, Bordeaux.

Drafting of the manuscript: Tripathi, Knusel, Ezaldein, Honaker.

Critical revision of the manuscript for important intellectual content: All authors.

Statistical analysis: Knusel, Honaker.

Administrative, technical, or material support: Tripathi, Scott.

Supervision: Tripathi, Ezaldein, Bordeaux, Scott.

Conflicts of Interest: Dr Tripathi reported grants from Brian Werbel Memorial Fund, Case Comprehensive Cancer Center, outside the submitted work. No other conflicts were reported.