SUBGROUPS FOR TARGETED TREATMENT BACK SCREENING TOOL
ICF Category	Measurement of limitation in activities and participation - completing the daily routine; purposeful sensory experiences, specified as repetitive perception of non-injurious sensory stimuli; and interacting according to social rules Measurement of impairment of body function – pain in back; pain in lower limb; content of thought; and thought functions, specified as the tendency to elaborate physical symptoms for cognitive/ideational reasons; appropriateness of emotion (mental functions that produce congruence of feeling or affect with the situation, such as happiness at receiving good news); range of emotion (mental functions that produce the spectrum of experience of arousal of affect or feelings such as love, hate, anxiousness, sorrow, joy, fear and anger); and emotional functions, specified as the tendency to elaborate physical symptoms for emotional/affective reasons
Description	The Subgroups for Targeted Treatment (STarT) Back Screening Tool is a 9-item screening measure used to identify subgroups of patients with low back pain in primary care settings based on the presence of potentially modifiable prognostic factors which may be useful in matching patients with targeted interventions.152 The STarT contains items related to physical (items 2, 3, 5, 6) and psychosocial (items 1, 4, 7, 8, 9) factors that have been identified as strong independent predictors for persistent disabling LBP.
Measurement method	Potential responses for the STarT are dichotomized (‘agree’ or ‘disagree’), with the exception of an item related to ‘bothersomeness’ which uses a 5-point Likert scale. Overall STarT scores (ranging from 0 to 9) are determined by summing all positive responses. Psychosocial subscale scores (ranging from 0 to 5) are determined by summing items related to bothersomeness, fear, catastrophizing, anxiety, and depression (i.e., items 1, 4, 7, 8, 9). Based on overall and psychosocial subscale scoring, the STarT categorizes patients as ‘high-risk’ (psychosocial subscale scores ≥4) in which high levels of psychosocial prognostic factors are present with or without physical factors present, ‘medium-risk’ (overall score >3; psychosocial subscale score <4) in which physical and psychosocial factors are present, but not a high level of psychosocial factors, or ‘low-risk’ (overall score 0–3) in which few prognostic factors are present.139
Nature of variable	Continuous subscale scores for function and psychosocial items & categorical subgroups
Units of measurement	Individual items: Bothersomeness item: (5-point Likert scale) Remaining items: (dichotomous scale) Subgroup scoring: High risk (psychosocial subscale scores ≥4) Medium risk (overall score >3; psychosocial subscale score <4) Low risk (overall score ≤3)
Measurement properties	The STarT overall (0.79, 95% CI: 0.73 – 0.95) and psychosocial subscale (0.76, 95% CI: 0.52 – 0.89) scores has been found to have acceptable test-retest reliability (weighted kappa values) in patients with stable symptoms.152 Cronbach’s alpha estimates for overall (.79) and psychosocial subscale (.74) scores suggest the STarT has demonstrates internal consistency.152 The predictive validity of the STarT has been reported in which sub grouping cutoff scores were predictive of poor 6-month disability outcomes in low (16.7%), medium (53.2%), and high (78.4%) risk subgroups.152 The discriminant validity of the STarT scores (AUC range: 0.73 – 0.92) have been reported and suggest that overall scores best discriminate physical reference standards (eg, disability and referred leg pain), while psychosocial subscale scores best discriminate psychosocial reference standards (eg, catastrophizing, fear, and depression).152 The STarT has demonstrated concurrent validity in comparison to the Örebro Musculoskeletal Pain Screening Questionnaire, in which both instruments displayed similar subgroup characteristics and the ability to discriminate for disability, catastrophizing, fear, comorbid pain and time off work reference standards.153 Subgroup status has corresponded to initial pain intensity and disability scores in an ordinal manner for patients seeking care in outpatient physical therapy settings and longitudinal analyses indicated different patterns of change for clinical outcomes.100