key: cord-0022503-3gxzz1ts authors: Johnson, Karl T.; Palakshappa, Deepak; Basu, Sanjay; Seligman, Hilary; Berkowitz, Seth A. title: Examining the bidirectional relationship between food insecurity and healthcare spending date: 2021-02-17 journal: Health Serv Res DOI: 10.1111/1475-6773.13641 sha: b32f7a6d0e8ad3abde3d5c6bebb1cdf5eb28d949 doc_id: 22503 cord_uid: 3gxzz1ts OBJECTIVE: To improve food insecurity interventions, we sought to better understand the hypothesized bidirectional relationship between food insecurity and health care expenditures. DATA SOURCE: Nationally representative sample of the civilian noninstitutionalized population of the United States (2016‐2017 Medical Expenditure Panel Survey [MEPS]). STUDY DESIGN: In a retrospective longitudinal cohort, we conducted two sets of analyses: (a) two‐part models to examine the association between food insecurity in 2016 and health care expenditures in 2017; and (b) logistic regression models to examine the association between health care expenditures in 2016 and food insecurity in 2017. We adjusted for demographic and socioeconomic variables as well as 2016 health care expenditures and food insecurity. DATA COLLECTION: Health care expenditures, food insecurity, and medical condition data from 10 886 adults who were included in 2016‐2017 MEPS. PRINCIPAL FINDINGS: Food insecurity in 2016, compared with being food secure, was associated with both a higher odds of having any health care expenditures in 2017 (OR 1.29, 95% CI: 1.04 to 1.60) and greater total expenditures ($1738.88 greater, 95% CI: $354.10 to $3123.57), which represents approximately 25% greater expenditures. Greater 2016 health care expenditures were associated with slightly higher odds of being food insecure in 2017 (OR 1.007 per $1000 in expenditures, 95% CI: 1.002 to 1.012, P =0.01). Exploratory analyses suggested that poor health status may underlie the relationship between food insecurity and health care expenditures. CONCLUSIONS: A bidirectional relationship exists between food insecurity and health care expenditures, but the strength of either direction appears unequal. Higher health care expenditures are associated with a slightly greater risk of being food insecure (adjusted for baseline food insecurity status) but being food insecure is associated with substantially greater subsequent health care expenditures (adjusted for baseline health care expenditures). Interventions to address food insecurity and poor health may be helpful to break this cycle. Food insecurity, inconsistent access to enough food for an active, healthy life, affected over 37 million Americans in 2018 (11.1% of households). 1 Early reports suggest that food insecurity has nearly tripled as a consequence of the COVID-19 pandemic. 2 Food insecurity is associated with a range of cardiometabolic (eg, diabetes mellitus, coronary heart disease) and other chronic conditions. [3] [4] [5] [6] [7] [8] Reasons for these associations include lower diet quality, tradeoffs between food and other necessities such as medications, and the stress of food insecurity which shifts attentions toward meeting immediate needs and away from long-term health. 3, [9] [10] [11] Food insecurity is also associated with more emergency department visits, inpatient hospitalizations, and greater health care expenditures. [12] [13] [14] [15] [16] For these reasons, food insecurity has emerged as a key target for programs that seek to address health-related social needs in order to improve health, reduce hospitalizations, and lower health care costs. 17, 18 However, much remains to be understood about the relationship between food insecurity and health care expenditures. A leading conceptual model 3 posits a "bidirectional" relationship such that food insecurity is associated with worse health (leading to greater health care expenditures), but also that poor health (and associated greater health care expenditures) can lead households to become food insecure (eg, by impeding the ability to work or diverting resources needed for food toward medical expenses) ( Figure 1 ). While both directions are plausible, it has been difficult to examine this hypothesis in detail owing to lack of data. Specifically, nationally representative data that simultaneously assess food insecurity and health care expenditures at two time points have not previously been available. This represents an important knowledge gap, particularly with regard to food insecurity interventions. Better understanding the strength of the relationship between food insecurity and health care costs, in both directions, would inform interventions that seek to break this vicious cycle. In this study, we take advantage of recently available data from the Medical Expenditure Panel Survey (MEPS), 19 which assesses food insecurity and health care expenditures longitudinally. We use these data to examine the bidirectional hypothesis, examining whether food insecurity, accounting for baseline health care expenditures, is associated with greater subsequent health care expenditures, and whether health care expenditures, accounting for baseline food insecurity, are associated with subsequent food insecurity risk. In keeping with our conceptual model, we hypothesize support for both associations. odds of being food insecure in 2017 (OR 1.007 per $1000 in expenditures, 95% CI: 1.002 to 1.012, P =0.01). Exploratory analyses suggested that poor health status may underlie the relationship between food insecurity and health care expenditures. • Utilizing a nationally representative panel survey that, for the first time, includes information on individual food insecurity and health care expenditures across at least two years, we demonstrate that a bidirectional relationship exists between food insecurity and health care expenditures. • However, the association between food insecurity and health care expenditures in the following year appears larger than the association between health care expenditures and food insecurity in the following year. • To break the cycle between food insecurity and health care expenditures, interventions that address food insecurity may have greater impact than those that offset health care expenditures. Given the bidirectional hypothesis examined in this study, two measures constituted either the main outcome or the exposure variable in our analysis: food insecurity status and annual health care expenditures. In accordance with the typical USDA scoring system, food security status was categorized as food insecure if a positive response was recorded for any two or more questions within the 10-item food insecurity questionnaire, and as food secure otherwise. 20 Annual health care expenditures (total and broken down by type: inpatient, outpatient, emergency department, prescription drug, and out-of-pocket) were gathered from MEPS and expressed as continuous variables. According to AHRQ, "expenditures in MEPS are comprised of direct payments for care provided during the year, including out-of-pocket payments and payments by private insurance, Medicaid, Medicare, and other sources." 19 The potential association between food insecurity and health care ex- and disabilities (determined by reported limitations in any of the following domains: ambulatory, cognitive, hearing, vision, independent living or self-care). We also extracted information on self-reported medical debt, 23 to examine how this may relate to food insecurity and health care expenditures. Medical debt was expressed as a binary variable and positive if an affirmative response was recorded for any of three questions concerning problems with paying medical bills, medical bills being paid off over time, or having medical bills that are unable to be paid off. This study consisted of two main analyses. The first considered the association between food insecurity status in 2016 and total health care expenditures in 2017. Given known difficulties in modeling health care expenditures (eg, point mass at zero, extreme observations), we used a two-part model. 24 19 Because missingness for any variable was <5%, missing data were not imputed. Given the two main analyses, a two-sided P-value < 0.025 was taken to indicate statistical significance. In a set of secondary analyses, we considered the bidirectional re- To better understand potential mechanisms underlying the relationship between total health care expenditures in 2016 and food insecurity in 2017, we conducted several exploratory analyses. Given that individuals may be food insecure due to financial trade-offs between food and competing expenses, we sought to understand how medical debt may affect the association between food insecurity and health care expenditures. We interrogated this mechanism by incorporating an indicator of medical debt into our main analysis. Next, if the association between health care expenditures and food insecurity is in large part based on health care expenditures serving as an indicator for poor health status, then adjusting for other indicators of poor health should weaken this association. To assess this idea, we conducted an exploratory analysis in which we added a self-reported disability variable to our main analysis. Our final study sample consisted of 10 866 respondents. In 2016, 1365 (weighted percent 8.97%) of our sample were food insecure (Table 1) . Among other differences, compared with those who were food secure in 2016, those who were food insecure in 2016 were more likely to selfidentify as a racial/ethnic minority, be uninsured, have medical debt, and less likely to have a high school diploma or have private insurance. To examine how food insecurity may be associated with specific categories of health care expenditures, we refit our main analyses while replacing total health care expenditures with specific expenditure categories as the outcome. Associations between food insecurity and these categories were most pronounced for prescription spending ( sizes prevented definitive conclusions from being drawn ( Table 4 ). The magnitude of the association between food insecurity and having any health care expenditures (1st part of the model) was greater among those with comorbidities compared to the overall population. The magnitude of the association between food insecurity and expenditures among those who had any expenditures (2nd part of the model) was similar to or slightly smaller among those with comorbidities compared to the overall population. Estimated expenditures within all subpopulations are presented in Appendix S1: Table S4 . To assess for the mechanisms by which the relationship between total health care expenditures in 2016 and food insecurity status in 2017 may exist, we analyzed three additional models, which further adjusted for the total number of inpatient days, medical status, and disability status. When adjusting our main analysis for medical debt, the associa- Analyses examining the relationship between food insecurity as exposure and health care expenditures as outcome were not substantively changed by using alternative distributions (Appendix S1: Table S1 ). Different winsorizing thresholds did not meaningfully change results (Appendix S1: Table S5 ). When expressing 2016 health care expenditures as a categorical variable, the association between 2016 food insecurity and the presence of any 2017 health care expenditures was weaker than in the main analyses, but the association between 2016 food insecurity and 2017 total health care expenditures among those who had any expenditures was similar (Appendix S1: Table S6 ). Adjusting for both 2016 and 2017 health insurance did not affect the results. In this study of nationally representative data, we found support for both directions of the relationship between food insecurity and healthcare expenditures-food insecurity is associated with greater health care expenditures, and greater health care expenditures are associated with food insecurity. However, the strength of these associations appears to be unequal. Though we found a statistically significant association between health care expenditures and subsequent food insecurity, the difference in odds () was small-about 1% greater risk of food insecurity per $1000 difference in health care The results of this study have several implications. First, the confluence of comorbidities, health care expenditures, and food insecurity suggests that attempting to address food insecurity without paying attention to comorbidity could limit the effectiveness of the intervention. Rather than viewing food insecurity as one standalone issue to address, it may be more effective to think of addressing food insecurity as one aspect of a more comprehensive disease management plan. Relatedly, given that the strength of the association appears larger when food insecurity is the predictor and greater health care expenditures is the outcome (compared with when these roles are reversed), disease management plans, which target the upstream determinants of food insecurity and general poor health, may be more efficacious at breaking this cycle than interventions that merely offset the cost of disease management. Thirdly, the category of prescription expenditures stands out in our analyses. One reason for this may be that if food insecurity increases the risk for the development or worsening of chronic conditions, it could lead to increasingly complicated medication regimens, with attendant costs. 3 Finally, the lack of association between out-of-pocket expenditures and food insecurity, coupled with a strong association between medical debt and food insecurity, warrants closer attention. Current insurance benefit design often considers out-of-pocket expenditures (eg, yearly out-of-pocket maximums set at an absolute number) without considering medical debt. More nuanced design that takes into account an individual's ability to match resources to expenditures (eg, yearly out-of-pocket maximums set as a percentage of income or assets) may better protect individuals from the consequences of out-of-pocket costs. The results of this study should be interpreted in light of several limitations. This study is observational, and unmeasured factors could confound the associations seen. Though the longitudinal design provides protection against unmeasured time-invariant factors, we cannot exclude the possible role of unmeasured time-varying factors. Next, the disability indicator used is a very blunt indicator of health status. Sample size did not permit more granular investigations (eg, of specific disabilities), but this is an important direction for future work. Similarly, small sample sizes increased the uncertainty of estimates conducted in chronic disease subgroups. Third, the two-year time frame of this study is too short to permit investigation of some relevant pathways. For example, a key mechanism through which food insecurity may increase health care expenditures is through greater incidence of expensive chronic conditions, such as diabetes. However, as the annual incidence of diabetes is very low compared with its prevalence, we were unable to investigate that potential pathway in this study. These limitations, however, are balanced by several strengths. Data came from a large, nationally representative survey that used validated methods to assess food insecurity and health care expenditures. The longitudinal design allowed us to establish the time ordering of exposures and outcomes, and in sensitivity analyses, results were robust to alternative specifications and modeling strategies. In this longitudinal study of nationally representative MEPS data, we found that food insecurity was associated with higher subsequent health care expenditures and that health care expenditures were associated with greater risk for subsequent food insecurity. However, these two associations appeared to be of different strengths. The association from health care expenditures to subsequent food insecurity showed a 1% difference in odds per $1000 difference in health care expenditures, but the association between food insecurity and subsequent health care expenditures showed 25% greater health care expenditures for those who were food insecure, compared with food secure. The presence of these relationships sets up the potential for a self-reinforcing "vicious cycle" whereby food insecurity worsens health and worse health increases the risk for food insecurity. 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Twopm: two-part models Joint Acknowledgement/Disclosure Statement: Disclosures: SAB reports receiving personal fees from the Aspen Institute, outside the submitted work. All other authors report nothing to disclose. KTJ and SAB conceived of the study and drafted the manuscript. DP, SB, and HKS contributed to interpretation and revised the manuscript critically for important intellectual content. All authors give approval of the manuscript version to be submitted.