Spinal Manipulation Services vs. Prescription Drug Therapy for Long-term Care

Research Design

This description applies to project specific aim 2.

Overview of Design and Methods: FFS Medicare beneficiaries will be surveyed and compared by
cohort for differences in response. Subjects will be randomly sampled from each of the four
cohorts (A, B, A2B & B2A) identified in SA1.

Survey Instrument and Question Formulation: A validated survey instrument will be used to
collect subjective patient data. The survey will include questionnaires intended to evaluate
1) self-reported QOL, 2) satisfaction with care, and 3) beliefs regarding back pain and its
treatment. For assessment of self-reported QOL a version of the SF12 (Ware '96) will be used
and modified to account for time lapse between treatment for LBP and administration of the
survey, and to elicit treatment-specific responses The SF -12 has been previously validated
for measuring QOL among elderly patients, (Jakobsson '07) and patients using prescription
drugs. (Naveiro-Rilo '14) For assessment of satisfaction with care a 0-10 numeric scale will
be used. For assessment of beliefs a modified version of the validated LBP Treatment Beliefs
Questionnaire will be used. (Dima '15). A pre- test of all the survey instruments will be
conducted by distributing a prototype to a sample of 100 Medicare beneficiaries seen for LBP
at the SCU Health Center in Whittier, CA. Responses to the survey pre-test will inform any
need to edit the questionnaire for comprehensibility and ease of use, thus helping to ensure
instrument face validity. For ease of comprehension by older subjects, the survey questions
will be printed in large font and will be carefully worded to be brief, unambiguous, and free
of bias.

Survey Methods: ResDAC will initiate contact with random samples of beneficiaries who meet
criteria for inclusion in the cohorts identified in SA1. The Beneficiary Contact Service has
reviewed the survey plan with the PIs and provided an official cost estimate for this
service, which is routinely provided by the BCS with strict attention to patient protection.
Initial contact will be in the form of a Beneficiary Notification Letter, signed by the CMS
Privacy Officer. The letter will alert beneficiaries to the opportunity to voluntarily
participate in a healthcare survey. Recipients will be informed that they may decline
participation via enclosed reply forms, and will be given phone numbers to call CMS personnel
for additional information. After three weeks, the Beneficiary Contact Service will supply
the investigators with contact information for eligible beneficiaries (those who did not
decline to participate). The survey will be commenced by mailing the printed survey, cover
letter with informed consent form based on NCCIH guidelines, and a postage-paid return
envelope with detailed information about the survey. Participants can contact study personnel
if they have any questions. Follow up by phone after every two weeks or as needed will be
used to increase the rate of response.

Outcomes Measurement and Statistical Analysis: Testing will be done for between-cohort
differences in self-reported QOL, satisfaction with care, and beliefs about treatments for
LBP. Survey responses between the four groups will be compared using Pearson chi-square tests
and ANOVA. Demographic characteristics [e.g. sex as a biological variable, and age - because
age-related cognitive decline can affect survey responses (Wolinsky '15)] will be controlled
using linear regression for continuous survey items, proportional odds logistic regression
for ordinal items and multinomial regression for categorical items. In the multivariable
regression models equivalence between the four groups will be evaluated using likelihood
ratio or Wald tests. Given the multiplicity of testing (e.g. multiple groups for multiple
items), type I error inflation will be considered through used of Bonferonni corrections or
approaches for false discovery rates. Parametric tests of numeric data can be used to yield
unbiased answers when analyzing Likert scale responses. (Norman '10)

Inclusion Criteria:

- Subjects will include Medicare Fee for Service beneficiaries (male or female), aged 65-84
years, residing in the US, and enrolled under Medicare Parts A, B, and D who have
experienced an episode of chronic low back pain (defined as lasting three months or
longer).

Exclusion Criteria:

- Subjects with diagnosis of cancer will be excluded from the study population to avoid
confounding of the reason for use of prescription opioids. Subjects over the age of 85
will also be excluded.