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Table 1 Preliminary list of potential baseline variables and constructs (based on Hayden, 2007 Appendix)[31]

From: Exercise therapy for chronic low back pain: protocol for an individual participant data meta-analysis

Baseline variable construct Description/examples of potential measures
Individual subject characteristics
Age Current age
Sex Male, female
Body mass index (BMI) or height and weight BMI or measured height and individual weight
Lifestyle factors
Recreational participation Participation in sports activities or hobbies
Physical fitness Physical fitness level
Smoking Smoking habits
Alcohol consumption Amount/frequency of drinking, how often drunk
Coffee consumption Coffee consumed per day
Sociodemographic characteristics
Socio-economic status Education status, income
Work characteristics Employed, occupation
Social support Marital status
Overall health
General health status Perceived or self-rated health, general health question or Short Form-12, perceived energy level
Comorbidities Presence and type of co-morbidities (for example, musculoskeletal pain other than LBP, respiratory or stomach problems, migraines, multiple pain sites)
Previous injuries Previous sick leave (any cause or other than LBP), or accident
Receipt of compensation or litigation
Worker’s compensation; time off work; sick leave; benefits; pension Receipt of worker’s compensation, duration of time off work, sick leave due to LBP, benefits paid, pension application applied for or intending to apply for
Attribution for LBP Litigation, culpability for injury, job that caused pain, description of injury event
Previous low back pain (before the current episode)
Previous history of LBP Report of prior LBP
  Previous LBP treatment received (for example, injections, inpatient treatment, surgery)
  Prior claim for LBP, LBP sick leave, worker’s compensation injury
  Hospitalization due to LBP, previous lumbar spine radiography
Characteristics of the current LBP episode
Pain onset Onset of injury (for example, sudden or gradual), injury event or none
Duration of complaint LBP duration, time between injury and filing claim
Baseline LBP symptoms
Pain severity Injury severity rating, presence of disabling pain, visual analogue scale, presence of pain at night, NRS; McGill scale
Functional limitations Disability score (for example, RMDQ, Oswestry), assessment of functioning in leisure time
Change in symptoms Symptoms getting worse or better
Baseline physical examination findings
Range of motion (ROM) Change in ROM
Pain pattern (centralization) Pain pattern/directional preference according to McKenzie method
Other examination findings Summed physical exam, SLR, muscle palpation, gait, posture, walk test, ‘catch’, Waddell symptoms
Baseline neurological findings
Localization; nerve root; radiculopathy; pain on coughing Localization of pain to low back only, presence of nerve root signs/symptoms, clinical impression of radiculopathy with SLR, pain on coughing
Subject psychological status
Depression Rating scale of ‘feeling blue’, Beck Depression Inventory, GHQ depression scale, Zung Self-Rating Depression Scale
Other psychological diagnoses For example, hysteria, somatic symptoms, hypochondriasis
Other psychological characteristics and behaviors For example, self-esteem, pain behaviors, denial, state of anxiety, sleep problems, locus of control, fear avoidance beliefs, personality measures, active/passive coping mechanisms
LBP diagnosis received
Diagnostic categories Specific diagnostic categories (for example, sprain/strain, disc herniation)
Understanding of symptoms Patient’s understanding and accuracy of their symptoms
Subject expectations of recovery
Subjective work ability Subjective work capacity in relation to complaint
Perceived ability to do job Perceptions regarding ability to do job, expectations with injury
Psychosocial capacity to RTW Psychosocial capacity to RTW, Worker Role Interview
Intent/expectations to RTW Intent/expectations to return to job
Other baseline/LBP episode characteristics
  1. NRS: numeric rating scale.
  2. RMDQ: Roland Morris Disability Questionnaire.
  3. SLR: straight leg raise.
  4. GHQ: general health questionnaire.
  5. RTW: return to work.