Health and Quality of Life Outcomes (Apr 2021)

The patient enablement instrument for back pain: reliability, content validity, construct validity and responsiveness

  • A. Molgaard Nielsen,
  • J. Hartvigsen,
  • A. Kongsted,
  • B. Öberg,
  • P. Enthoven,
  • A. Abbott,
  • H. H. Lauridsen

DOI
https://doi.org/10.1186/s12955-021-01758-0
Journal volume & issue
Vol. 19, no. 1
pp. 1 – 14

Abstract

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Abstract Background Currently, there are no outcome measures assessing the ability of people with non-specific low back pain to self-manage their illness. Inspired by the ‘Patient Enablement Instrument’, we developed the Patient Enablement Instrument for Back Pain (PEI-BP). The aim of this study was to describe the development of the Patient Enablement Instrument for Back Pain (PEI-BP) and investigate content validity, construct validity, internal consistency, test–retest reliability, measurement error, responsiveness and floor and ceiling effects. Methods The PEI-BP consists of 6 items that are rated on a 0–10 Numeric Rating Scale. Measurement properties were evaluated using the COSMIN taxonomy and were based on three cohorts from primary care with low back pain: The content validity cohort (N = 14) which participated in semi-structured interviews, the GLA:D® Back cohort (N = 272) and the test–retest cohort (N = 37) which both completed self-reported questionnaires. For construct validity and responsiveness, enablement was compared to disability (Oswestry Disability Index), back pain beliefs (Brief Illness Perception Questionnaire), fear avoidance (Fear-Avoidance Beliefs Questionnaire—physical activity), mental health (SF-36), educational level and number of previous episodes of low back pain. Results The PEI-BP was found to have acceptable content validity, construct validity, reliability (internal consistency, test–retest reliability and measurement error) and responsiveness. The Smallest Detectable Change was 10.1 points illustrating that a patient would have to change more than 1/6 of the scale range for it to be a true change. A skewed distribution towards the high scores were found at baseline indicating a potentially problematic ceiling effect in the current population. Conclusions The PEI-BP can be considered a valid and reliable tool to measure enablement on people seeking care for non-specific LBP. Further testing of the PEI-BP in populations with more severe LBP is recommended. Trial registration: Not applicable.

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