Table 1.

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

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

NRS: numeric rating scale.

RMDQ: Roland Morris Disability Questionnaire.

SLR: straight leg raise.

GHQ: general health questionnaire.

RTW: return to work.