The Association Between Self-Rated Mental Health Status and Total Health Care Expenditure

Both clinical diagnoses and self-rated measures of mental illness are associated with a variety of outcomes, including physical well-being, health utilization, and expenditure. However, much of current literature primarily utilizes clinically diagnosed data. This cross-sectional study explores the impact of mental illness and health care expenditure using 2 self-rated measures: self-rated measured of perceived mental health status (SRMH) and Kessler Screening Scale for Psychological Distress (K6). Data from the 2011 Medical Expenditure Panel Survey Household Component, a nationally representative sample of noninstitutionalized individuals (n1⁄4 18,295), were analyzed using bivariate x tests and a 2part model (logistics regression and generalized linear model regression for the first and second stages, respectively). Although predictive of any health expenditure, SRMH alone was not highly predictive of the dollar value of that health expenditure conditional on any spending. By comparison, the K6 measure was significantly and positively associated with the probability of any health expenditure as well as the dollar value of that spending. Taken together, both the K6 and SRMH measures suggest a positive relationship between poor mental health and the probability of any health expenditure and total expenditure conditional on any spending, even when adjusting for other confounding factors such as race/ethnicity, sex, age, educational attainment, insurance status, and some regional characteristics. Our results suggest that psychological distress and SRMH may represent potential pathways linking poor mental health to increased health care expenditure. Further research exploring the nuances of these relationships may aid researchers, practitioners, and policy makers in addressing issues of inflated health care expenditure in populations at risk for poor mental health. (Medicine 94(35):e1410) Abbreviations: BRR = balanced repeated replication, GLM = generalized linear model, K6 = Kessler Screening Scale for Psychological Distress, MEPS = Medical Expenditure Panel n, MPH, and Courtney Keeler, PhD INTRODUCTION M ental illness persists as a pressing public health issue. Indiscriminate of demographic and socioeconomic status, mental illness has a widespread impact that affects individuals of all ages, ethnicities, and income levels. A 2014 report from the Substance Abuse and Mental Health Services Administration estimated that 42.5 million adults in the United States experienced mental illness in the past year; moreover, the National Institute of Mental Health (NIMH) further reported that 1 in 17 Americans currently live with a serious mental illness. Although these statistics are startlingly high, the actual prevalence is likely higher. Although the majority of severe cases of mental illness will encounter professional treatment, many individuals fly under the radar; nevertheless, just because an individual remains untreated, it does not imply that the individual does not need treatment. As a result, stated prevalence values likely underrepresent need, especially among those with moderate mental health illness. Because many mental health conditions remain undiagnosed, self-rated assessment tools provide a useful and perhaps more revealing indicator of mental well-being. Existing literature demonstrates the reliability of both self-rated assessment tools and more formal screening tools. When assessed by both clinical diagnoses and self-rated measures, mental illness was associated with a variety of outcomes, including physical health, health utilization, and expenditure. However, the predominant method of measuring mental illness in the literature continues to be clinical diagnoses, a method that necessarily excludes individuals with ‘‘poor’’ mental health who remain undiagnosed. As such, self-rated measures may capture a more comprehensive understanding of mental health in the general population. These sorts of measures may also help researchers better understand how mental health relates to other important outcomes such as health expenditure. The literature has shown that the association between mental health and patterns of health care cost may be more pronounced when using self-rated measures because individuals who have undiagnosed mental illness utilize similar medical services as those who are diagnosed. This article examined the impact of mental illness on health expenditure through self-rated mental health (SRMH) measures. Drawing on the 2011 household component of the Medical Expenditure Panel Survey (MEPS), we relied on 2 measures of SRMH: a Likert-style measure assessing whether an individual rates oneself to be in ‘‘excellent, very good, good, fair, or poor’’ mental health, which we broke into 5 separate dummy variables, and (2) the self-rated Kessler Screening Scale for Psychological Distress (K6). In defining expenditure, we considered total health care expense, including both indemniments. We hypothesized that individuals SRMH experience elevated health care www.md-journal.com | 1