Chronic Spinal Pain and Financial Worries in the US Adult Population

Haiou Yang, PhD; Scott Haldeman, DC, MD, PhD, FRCP(C), FAAN


Spine. 2020;45(8):528-533. 

In This Article

Materials and Methods

Study Design and Data Source

Data for this study come from the 2015 National Health Interview Survey (NHIS) which provides a nationally representative sample in the United States on various health-related topics. The NHIS data are collected through face-to-face interviews of all individuals living in a particular house with a core questionnaire.[14] The core interview data are compiled in the Person file and supplementary interviews data are compiled in the Sample Adult file. The final response rate for the Sample Adult component is 79.7% for the 2015 NHIS.[15] The study population was the adult aged 18 to 85 and the total population size included in the analysis was 33,672. Data from the 2015 NHIS provide a unique opportunity to explore the associations between chronic spinal pain and financial worries, as the assessment of financial worries is added for the first time, whereas the data on nonspecific low back pain and nonspecific neck pain are the core question items that have been collected.[14]

Assessment of Chronic Spinal Pains

In this study, the major health outcome was chronic spinal pain with two indicators based on two survey questions in the NHIS related to chronic spinal pain: nonspecific low back pain in the past 3 months and nonspecific neck pain in the past 3 months. The two indicators of chronic spinal pains were defined as: (a) low back pain and neck pain which was defined based on "Yes" responses to both questions on low back pain and neck pain in the past 3 months. (b) low back pain and/or neck pain, which was based on "Yes" response to the question on low back pain or "Yes" response to the question on neck pain.

The definition of chronic low back pain in the NHIS is generally consistent with the research standards of chronic low back pain of the National Institutes of Health Research Task Force on which defines chronic back pain as a back pain problem that has persisted at least 3 months and has resulted in pain on at least half the days in the past 6 months.[16] The definition of chronic neck pain in the 2015 NHIS is consistent with the measurement of chronic neck pain defined by the Bone and Joint Decade 2000–2010 Task Force on Neck Pain.[17,18]

Assessment of Financial Worries

Financial worries were assessed through a set of eight questions: "How worried are you right now about not being able to …": (1) pay monthly bills, (2) maintain standard of living, (3) make minimum credit card payments, (4) pay rent/mortgage/housing costs, (5) pay medical costs for normal healthcare, (6) have enough money for retirement, (7) pay medical costs of illness/accident, and (8) pay for children's college. The response format was a 4-point Likert scale from "Very worried" to "Not worried at all." Very worried was coded "Yes" for the type of financial worry reported, and "No" for "Moderately worried," "Not too worried," and "Not worried at all" for the type of financial worries. Eight dummy variables on each dimension of financial worry were developed. An additional variable assessing degree of financial worry was constructed with four subgroups: (a) "No financial worry"; (b) "One type of financial worry"; (c) "two to three types of financial worries"; and (d) "four to eight more types of financial worries."

Assessment of Demographic and Socioeconomic Characteristics

Demographic factors controlled for the analysis included sex, age, and ethnicity. Age was coded into six age groups: (a) 18–25, (b) 26–40, (c) 41–55, (d) 56–65, (e) 66–75, and (f) 76–85. Race and ethnicity were coded into five groups: (a) Non-Hispanic White, (b) Non-Hispanic Black, (c) Hispanic, (d) Non-Hispanic Asian, and (e) Non-Hispanic Others. Socioeconomic status variables included in the analysis were education and income. Education was coded into five categories: less than high school, high school, some college, college, and master and higher. Income was defined as personal yearly earning coded into four categories: less than $14,999, $15,000 to $34,999, $35,000 to $64,999, and $65,000 and higher.

Data Analysis Methods

To account for the complex sampling design, the Taylor linearized variance estimation method in STATA 12 (StataCorp, College Station, TX) was used.

Nine sets of logistic regression models were constructed to explore the associations between chronic spinal pain and financial worries. In these models, demographic (age, sex, and race and ethnicity) and socioeconomic characteristics (education and earnings) were controlled as confounders. Multivariable logistic regression with odds ratios (ORs) and 95% confidence interval (CI) were calculated as measures of associations. The first eight sets of the models aimed at exploring the associations between eight individual types of worries and low back and neck pain, as well as low back and/or neck pain. The last set of the models focused on the linkage between chronic spinal pain and the number of financial worries.