3.2 Summary of key data retrieved from full-text reviews
Despite no restrictions being placed on year of publication, all the studies meeting the inclusion criteria were published in 2010 or later, and all were cross-sectional in design (Table 1). They employed structured questionnaires, apart from one mixed methods study which also used interviews. In terms of country of origin, two studies were conducted in Australia, four in the United States of America, three in Europe (Germany, Austria, Switzerland and Italy), one in Saudi Arabia. Five of the cross-sectional studies solely studied patients with back pain, while the other five studies included back pain as a significant portion of their patient population (> 10%), one of which provided a subpopulation analysis of patients with back pain.
All ten studies focused on adult populations (≥ 18 years) and had a majority female population, with one study having entirely female participants. Ethnic break-down was only provided by two USA studies, both of which had predominantly white study populations. Nine studies collected data on education level, most reporting an even spread across participants.
Table 2 here.
Table 2
HL and back pain Health Outcome measures used and their relationship.
Briggs et al. 2010 (15) |
HL measure | Health Outcome (HO) | HO measure | Relationship between HO and HL |
Short-form Test of Functional Health Literacy in Adults (S-TOFHLA) | Pain severity | Numeric pain-rating scale | Unspecified. |
Pain impact | Low back pain episodes (last 1 year), workdays missed, sought health professional advice, medication use, intrusion on regular daily and recreational activities. | Unspecified. |
Low back pain related disability | Oswestry Disability Index (ODI) | Unspecified. |
Fear avoidance | Fear Avoidance Beliefs Questionnaire (FABQ) | No significant relationship. |
Beliefs about low back pain | Back Pain Beliefs Questionnaire (BBQ) | No significant relationship. |
Catastrophising | Coping Skills Questionnaire (CSQ) | No significant relationship. |
Beliefs on “cause and course of low back pain”, and “seeking, understanding and utilising low back pain information”. | Telephone interviews | Unspecified correlation to HL. However, participants reported obstacles in seeking, comprehending and using low back pain information, which were not reflected in S-TOFHLA scores. |
Briggs et al. 2011 (33) |
HL measure | Health Outcome (HO) | HO measure | Relationship between HO and HL |
Health Literacy Measurement Scale (HeLMS) | Same as Briggs 2010 | Same as Briggs 2010 | Chronic low back pain associated with lower scores in HeLMS domain 1: ‘Patient attitudes towards their health’ and greater difficulty in managing personal health. |
Camerini et al. 2015 (39) |
HL measure | Health Outcome (HO) | HO measure | Relationship between HO and HL |
Low Back Pain Knowledge Questionnaire | Patient empowerment | Psychological Empowerment Scale | No significant relationship. |
| Patient involvement | Modified Patients’ Perceived Involvement in Care Scale (M-PICS) | Low HL group more inclined to ask healthcare provider for information regarding treatment plan. |
| Medication non-adherence | Pain Medication Questionnaire | No significant relationship. |
| Health outcomes | 6 questions from the Chronic Pain Grading Scale on intensity and functionality | No significant relationship. |
Glassman et al. 2019 (35) |
HL measure | Health Outcome (HO) | HO measure | Relationship between HO and HL |
Newest Vital Sign (NVS) | Low back pain related disability | Oswestry Disability Index | No significant relationship. |
Health Literacy Assessment (HLA) | Pain | Numeric Rating Scales for Back and Leg Pain | Lower HL associated with higher back pain scores. |
| Generic health status | Euro-QOL5D (EQ-5D) | No significant relationship. |
| | Utilisation of lumbar spine treatment (last 6 months), physiotherapy attendance, immunisation history, medication use, employment, days of work missed. | Adequate HL group used more medications and consulted a specialist more frequently than limited HL group. Limited HL group reported more individual visits to chiropractor and had lower use of NSAIDs. |
Table 2
Al-Eisa et al. 2017 (36) |
HL measure | Health Outcome (HO) | HO measure | Relationship between HO and HL |
Newest Vital Sign (NVS) | Disability level for low back pain | Oswestry Disability Index | Disability was negatively correlated with HL. |
| Avoidance behaviour due to pain | Fear Avoidance Beliefs' Questionnaire (FABQ) | Negative correlation between FAB (in terms of Physical Activity) and HL. No significant relationship between FAB (in terms of work) and HL. |
Devraj et al. 2013 (17) |
HL measure | Health Outcome (HO) | HO measure | Relationship between HO and HL |
Newest Vital Sign (NVS) | Pain awareness and medication knowledge | 12-question survey based on chronic pain guidelines, patient education resources, and previous studies. | Limited HL associated with lower ability to find healthcare providers to manage chronic pain, less likely to know alternative methods to treat pain besides medications alone, and less likely to know over-the-counter medications to take for pain control. |
| Pain severity | 100 mm Visual Analogue Scale (VAS) - (pain severity over the past week). | No significant relationship. |
MacLeod et al. 2017 (40) |
HL measure | Health Outcome (HO) | HO measure | Relationship between HO and HL |
“How confident are you filling out medical forms by yourself?” screening question. | Patient dissatisfaction | Modified Consumer Assessment of Healthcare Providers and Systems (CAHPS) survey. 10-point scales measuring dissatisfaction with general healthcare, specialists, physicians, and AARP Medicare Supplement Insurance plans. | Inadequate HL associated with greater dissatisfaction with healthcare system and general healthcare (e.g. physicians, specialists, insurers, and general experiences). |
Preventive services or quality of care | Administrative medical claims databases. | Inadequate HL associated with reduced compliance towards preventive healthcare services and less uptake of flu immunisations. |
Healthcare utilization and expenditures | Administrative medical claims databases. | Inadequate HL associated with higher emergency department attendance, inpatient admission and yearly healthcare expenditure. |
Burke et al. 2015 (41) |
HL measure | Health Outcome (HO) | HO measure | Relationship between HO and HL |
“Never heard of it / Do not know much about it” questions from the NHIS (National Health Interview Survey). | Lack of need | “Do not need it” from the NHIS (National Health Interview Survey). | No significant relationship. |
Health Status | Self-reported health status, functional limitation, hospitalization and emergency department attendance (last 12 months). | No significant relationship. |
Health Behaviours | Activity level, smoking status, alcohol consumption level, body mass index, flu immunisation (last 12 months), use of pneumonia vaccine. | Low HL associated lower activity level. |
Healthcare Access | Healthcare provider visits (last 12 months), health insurance coverage, delayed healthcare due to cost concerns, delayed healthcare due to non-cost concerns, ability to afford common supplementary healthcare. | Low HL associated with greater inability to afford ancillary care. |
Table 3 here.
Table 3
HL measures used and the components of HL they cover
HL measure | Functional HL | Communicative HL | Critical HL | Number of studies - HL measure used (%) |
Short-form Test of Functional Health Literacy in Adults (S-TOFHLA) | YES | NO | NO | 1 (9.1%) |
Health Literacy Measurement Scale (HeLMS) | YES | YES | YES | 1 (9.1%) |
Low Back Pain Knowledge Questionnaire | NO | NO | YES | 1 (9.1%) |
Newest Vital Sign (NVS) | YES | NO | NO | 3 (27.3%) |
Health Literacy Assessment (HLA) | YES | NO | NO | 1 (9.1%) |
“How confident are you filling out medical forms by yourself?” screening question | NO | NO | YES | 1 (9.1%) |
“Never heard of it / Do not know much about it” questions from the NHIS (National Health Interview Survey) | NO | NO | YES | 1 (9.1%) |
HELP questionnaire (health education literacy of patients with chronic musculoskeletal diseases) | YES | YES | NO | 1 (9.1%) |
3 screening questions from Brief Questions to Identify Patients with Inadequate Health Literacy | YES | YES | NO | 1 (9.1%) |
Number of studies - HL component assessed (%) | 8 (72.7%) | 3 (27.3%) | 4 (36.4%) | Total times HL measures used: 11 |
3.3 Summary of HL measures used
Nine different HL measures were employed across the ten studies (Table 2). Most HL measures assessed functional HL (72.7%), while the number that evaluated communicative and critical HL were fewer than half (27.3% and 36.4% respectively) (Table 3).
In their 2010 paper, Briggs et al. (15) used the short-form Test of Functional Health Literacy in Adults (S-TOFHLA), which assesses ‘functional’ HL, defined as reading, writing and numeracy skills in relation to healthcare (1, 34). The S-TOFHLA does so via the use of two prose passages and four items testing numeracy. Briggs et al. (15) also employed telephone interviews to assess HL by asking participants on how they sought, understood and utilised back pain information.
Subsequently in their 2011 paper, Briggs et al. used the Health Literacy Measurement Scale (HeLMS) (33), which goes beyond functional HL to include communication skills, computation skills, and social support, thereby overcoming limitations of the S-TOFHLA (33). The HeLMS sets out to assess “overall capacity to seek, understand and use health information within the healthcare setting” by asking questions such as “Are you able to see a doctor when you need to?” (33). By doing so it assesses all three domains of health literacy, Functional, Communicative and Critical HL.
The Newest Vital Sign (NVS) was the most frequently used HL measure (Table 3), utilised by Glassman et al., Al-Eisa, Buragadda and Melam, and Devraj, Herndon and Griffin (17, 35, 36). The NVS is convenient to use and has a sensitivity equivalent to the TOFHLA for identifying inadequate HL. It assesses functional HL through the asking of six questions regarding a standardised ice cream nutrition label (37).
Besides the NVS, Glassman et al. also used The Health Literacy Assessment, a 10-item self-administered questionnaire using items selected from the computerized Health LiTT measure (35). The Health Literacy Assessment (Health LiTT) assesses HL via three sections: Prose, Document and Quantitative (38). The Prose section asks participants to fill in missing words in a cloze passage, while the Document section consists of multiple-choice questions regarding images such as a prescription label. The Quantitative section also uses multiple-choice questions requiring arithmetic computation. By not assessing social skills and life choice decision making, the Health Literacy Assessment (Health LiTT) confines itself to Functional HL assessment only.
Camerini and Schulz (39) interpreted HL based on scores from the Low Back Pain Knowledge Questionnaire. The Questionnaire involved multiple-choice questions on topics such as the aetiology and management of low back pain. This neither quantifies one’s reading, numeracy nor social skills, but arguably involves decision making over treatment options and can be categorised as assessing critical HL.
Measurement of critical HL alone is also seen in other studies. MacLeod et al. used a single-item screener “How confident are you filling out medical forms by yourself?” (40), while Burke, Nahin and Stussman used the response option “Never heard of it/Do not know much about it” from the National Health Interview Survey (41).
Köppen et al. used HL questions taken from the Brief Questions to Identify Patients with Inadequate Health Literacy (8). These included the questions “how often do you have someone help you read hospital materials”, “how confident are you filling out medical forms by yourself” and “how often do you have problems learning about your medical condition because of difficulty understanding written information?” (8). These questions do offer a brief assessment of one’s reading and social skills, hence evaluating functional and communicative HL.
Finally, Farin, Ullrich and Nagl developed the HELP questionnaire (Health Education Literacy of Patients with chronic musculoskeletal diseases), an 18-item assessment that aims to summarise a patient’s reported communication and comprehension difficulties in health education and treatment (16). Questions such as “How much difficulty did you have communicating your own expectations and wishes in terms of your therapy?” were scored on Likert scales anchored from 1 to 5, with lower values indicating a higher HL. This instrument does not directly evaluate control over life events and choices and is categorised as covering only functional and communicative HL.
Table 4 here.
Table 4
Health outcome measures used by category
Health outcome measures employed (number of times) |
Pain | Disability | Behaviour | Knowledge and beliefs | Resource Utilisation |
Numerical rating scale (3) | Oswestry Disability Index (4) | Coping Skills Questionnaire (2) | Back Pain Beliefs Questionnaire (2) | Utilisation of medications (3) |
Visual Analogue scale (2) | Euro-QOL5D (1) | Fear Avoidance Beliefs Questionnaire (3) | Modified Consumer Assessment of Healthcare Providers and Systems survey (1) | Utilisation of healthcare appointments (9) |
6 item Chronic Pain Grading Scale (1) | 6 item Chronic Pain Grading Scale (1) | Psychological Empowerment Scale (1) | One-item measure - How would you rate your health? (1) | Healthcare cost - expenditure/workdays missed/affordability (6) |
Short-form McGill Pain Questionnaire (1) | | Modified Patients’ Perceived Involvement in Care Scale (1) | | |
Pain duration in months (1) | | | | |
Oswestry Disability Index (4) | | | | |
Euro-QOL5D (1) | | | | |
Others* (2) *Low back pain episodes in last 1 year | Others* (2) *Pain impact (intrusion on regular daily and recreational activities) | Others* (1) *Health Behaviours (Activity level, smoking status, alcohol consumption level, body mass index, flu immunisation in last 12 months, use of pneumonia vaccine) | Others* (3) *Telephone interviews (2), and 12-item survey developed by authors (1) | |
3.4 Summary of back pain outcomes retrieved from included studies
HL was associated with a heterogenous range of outcomes (Table 2). Five overarching categories summarising the studied back pain health outcomes were identified via framework method analysis (28, 29):
-
Pain
-
Disability
-
Behaviour
-
Knowledge and Beliefs
-
Resource Utilisation
3.4.1 Pain
Seven studies involved data on pain (8, 15, 17, 33, 35, 36, 39), using eight different measures. Pain intensity was the most frequently measured aspect, with three studies (Briggs et al., Briggs et al., Glassman et al.) employing the Numerical Rating Scale and two (Devraj, Herndon and Griffin, Köppen et al.) using the Visual Analogue Scale (Table 4). Pain intensity was also quantified as a sub-component of the Chronic Pain Grading (39), the Short-form McGill Pain Questionnaire (8), the Oswestry Disability Index (ODI) (15, 33, 35, 36), and the Euro-QOL5D (35). In addition, the Short-form McGill Pain Questionnaire assesses the nature of pain (42), while other studies looked at pain duration and frequency (Table 4).
3.4.2 Disability
Five studies involved data on disability (15, 33, 35, 36, 39). Four studies (Briggs et al., Briggs et al., Glassman et al., Al-Eisa, Buragadda and Melam) used the ODI, a spinal disorder-specific measure of disability which quantifies the difficulty faced in areas such as personal care, movements (e.g. lifting, walking, sitting), and lifestyle (e.g. sex life, travel) (43). Additionally, Glassman et al. (35) used the Euro-QOL5D (EQ-5D) which, in addition to mobility, self-care and activities of daily living, also screens for anxiety and depression. Both of Briggs et al.’s studies (15, 33) supplemented the ODI with an assessment of disability by asking participants on the amount of intrusion one faces in daily and recreational activities. Lastly, the Chronic Pain Grading Scale (39) also asks about functionality using such questions as “In the past 3 months, how much has this pain interfered with your daily activities (e.g. getting dressed, doing shopping)”.
3.4.3 Behaviour
Five studies collected data on patient behaviours (15, 33, 36, 39, 41), involving five forms of health outcome measures (Table 4). The Fear Avoidance Beliefs Questionnaire was most commonly used (Briggs et al., Briggs et al., Al-Eisa, Buragadda and Melam), and asks participants how much they think areas of physical activity and work would affect their back pain (44). Briggs et al. (15, 33) assessed pain catastrophizing with the Coping Skills Questionnaire. Camerini and Schulz (39) assessed patient empowerment and involvement with two scales, the Psychological Empowerment Scale and Modified Patients’ Perceived Involvement in Care Scale respectively, while Burke, Nahin and Stussman (41) studied the association between HL and health behaviours such as physical activity level and smoking status.
3.4.4 Knowledge and Beliefs
Four studies gathered data on patient knowledge and beliefs (15, 16, 17, 25), employing five different health outcome measures. Briggs et al. (15, 33) used the Back Pain Beliefs Questionnaire, which consists of 14 questions exploring beliefs regarding issues such as the management and prognosis of back trouble (45). They also conducted telephone interviews to understand participant’s beliefs regarding the aetiology and course of their back pain. MacLeod et al. (40) used the Modified Consumer Assessment of Healthcare Providers and Systems survey to assess patient dissatisfaction in areas such as general healthcare and doctors. Farin, Ullrich and Nagl (16) used a single-item measure - “How would you rate your health?” to evaluate participant beliefs on their health status. Finally, Devraj, Herndon and Griffin (17) developed a 12-item survey based on pre-existing pain guidelines and literature to assess the pain awareness and medication knowledge of their participants.
3.4.5 Resource utilisation
Four studies (Glassman et al., Camerini and Schulz, MacLeod et al., Burke, Nahin and Stussman) involved data on resource utilisation (35, 39–41). A wide variety of resources were studied, and we broadly grouped these outcomes (Table 4) into utilisation of medications, utilisation of healthcare appointments (e.g. lumbar spine treatment, physiotherapy), and healthcare costs (e.g. expenditure, workdays missed). Of these, utilisation of healthcare appointments was measured the most - in nine studies, while healthcare costs were measured six times, and utilisation of medications was measured thrice (Table 4).
Table 5 here.
Table 5
Summary of number of health outcome measures directly and indirectly related to the COS for clinical trials in non-specific low back pain
COS | Directly related outcomes | Indirectly related outcomes |
Pain intensity | 6 | 3 |
Physical functioning | 8 | 0 |
Health-related quality of life | 0 | 33 |
Number of deaths | 0 | 0 |
Totals (%) | 14 (28%) | 36 (72%) |
|
Appendix 2 – PRISMA-ScR Checklist (Tricco et al. 2018) |
Section | Item | PRISMA-ScR checklist item | Reported on page # |
Title | | | |
Title | 1 | Identify the report as a scoping review. | 1 |
Abstract | | | |
Structured summary | 2 | Provide a structured summary including, as applicable: background, objectives, eligibility criteria, sources of evidence, charting methods, results and conclusions that relate to the review question(s) and objective(s). | 2 |
Introduction | | | |
Rationale | 3 | Describe the rationale for the review in the context of what is already known. Explain why the review question(s)/objective(s) lend themselves to a scoping review approach. | 4–5 |
Objectives | 4 | Provide an explicit statement of the question(s) and objective(s) being addressed with reference to their key elements (e.g., population or participants, concepts and context), or other relevant key elements used to conceptualize the review question(s) and/or objective(s)). | 5 |
Methods | | | |
Protocol and registration | 5 | Indicate if a review protocol exists, if and where it can be accessed (e.g., web address), and, if available, provide registration information including registration number. | 6–7 |
Eligibility criteria | 6 | Specify the characteristics of the sources of evidence (e.g., years considered, language, publication status) used as criteria for eligibility, and provide a rationale. | 6 |
Information sources | 7 | Describe all information sources (e.g., databases with dates of coverage, contact with authors to identify additional sources) in the search, as well as the date the most recent search was executed. | 5–6 |
Search | 8 | Present the full electronic search strategy for at least one database, including any limits used, such that it could be repeated. | 30 |
Selection of sources of evidence | 9 | State the process for selecting sources of evidence (i.e., screening, eligibility) included in the scoping review. | 6–7 |
Appendix 2 – continued |
Section | Item | PRISMA-ScR checklist item | Reported on page # |
Data charting process | 10 | Describe the methods of charting data from the included sources of evidence (e.g., piloted forms; forms that have been tested by the team before their use, whether data charting was done independently, in duplicate) and any processes for obtaining and confirming data from investigators. | 7 |
Data items | 11 | List and define all variables for which data were sought and any assumptions and simplifications made. | 6 |
Critical appraisal of individual sources of evidence | 12 | If done, provide a rationale for conducting a critical appraisal of included sources of evidence; describe the methods used and how this information was used in any data synthesis (if appropriate). | NA |
Summary measures | 13 | Not applicable for scoping reviews. | NA |
Synthesis of results | 14 | Describe the methods of handling and summarizing the data that were charted. | 7 |
Risk of bias across studies | 15 | Not applicable for scoping reviews. | NA |
Additional analyses | 16 | Not applicable for scoping reviews. | NA |
Results | | | |
Selection of sources of evidence | 17 | Give numbers of sources of evidence screened, assessed for eligibility, and included in the review, with reasons for exclusions at each stage, ideally using a flow diagram. | 7 |
Characteristics of sources of evidence | 18 | For each source of evidence, present characteristics for which data were charted and provide the citations. | 23 |
Critical appraisal within sources of evidence | 19 | If done, present data on critical appraisal of included sources of evidence (see item 12). | NA |
Results of individual sources of evidence | 20 | For each included source of evidence, present the relevant data that were charted that relate to the review question(s) and objective(s). | 23–26 |
Synthesis of results | 21 | Summarize and/or present the charting results as they relate to the review question(s) and objective(s). | 7–13 |
Appendix 2 – continued |
Section | Item | PRISMA-ScR checklist item | Reported on page # |
Risk of bias across studies | 22 | Not applicable for scoping reviews. | NA |
Additional analyses | 23 | Not applicable for scoping reviews. | NA |
Discussion | | | |
Summary of evidence | 24 | Summarize the main results (including an overview of concepts, themes, and types of evidence available), explain how they relate to the review question(s) and objectives, and consider the relevance to key groups. | 13–16 |
Limitations | 25 | Discuss the limitations of the scoping review process. | 16 |
Conclusions | 26 | Provide a general interpretation of the results with respect to the review question(s) and objective(s), as well as potential implications and/or next steps. | 16–17 |
Funding | | | |
Funding | 27 | Describe sources of funding for the included sources of evidence, as well as sources of funding for the scoping review. Describe the role of the funders of the scoping review. | 1 |
3.5 Comparison of included back pain health outcomes against the COS for clinical trials in non-specific low back pain
A total of 50 health outcome measures were utilised across the ten studies reviewed. Of these, 14 (28%) were deemed to be directly related to those in the COS but were limited to two outcomes “pain intensity’ and “physical functioning” (18) (Table 5). The Pain Numerical Rating Scale, Pain Visual Analogue Scale, and Short-form McGill Pain Questionnaire directly addressed the core outcome of “pain intensity”, while the ODI, Euro-QOL5D, Chronic Pain Grading Scale, and questions on intrusion of daily and recreational activities (15, 33) directly addressed the outcome “physical functioning”. Measures on pain duration and frequency were only indirectly related. The COS “health-related quality of life” saw the greatest number of measures indirectly addressing it through outcomes on behaviour, knowledge and beliefs, and resource utilisation since these measures did not directly assess the “impact on physical, psychological and social domains of health” (18). The COS outcome “Number of Deaths” was not explored in any of the included studies.
3.6 Association between HL and back pain health outcomes
Although not a primary aim of this scoping review, we briefly detail here findings on the association between HL and back pain health outcomes (Table 2): out of six studies analysing the relation between HL and levels of pain and disability, only two found a significant association, particularly in the area of pain intensity. On behavioural impact, HL had no significant associations with fear avoidance, pain catastrophising, and psychological empowerment. However, patients with low HL were found to have a less active lifestyle. Considering patient knowledge and beliefs, those with lower HL had more difficulty identifying types and sources of treatment for back pain and were more dissatisfied with their care. However, no significant association was found between HL and beliefs about one’s future with back pain. Regarding resource utilisation, it seems that low HL was associated with higher utilisation of curative or symptomatic treatment (e.g. emergency room visits), and lower utilisation of preventive medicine (e.g. flu vaccinations).