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Table 4 Between-group comparisons on primary and secondary outcomes at 24-month follow-up (ANCOVA)

From: Feasibility and long-term efficacy of a proactive health program in the treatment of chronic back pain: a randomized controlled trial

  IG (N = 189) M+ (95% CI) CG (N = 255) M+ (95% CI) Between group
p Cohen’s d* [95% CI]
Primary outcomes
 Back pain severity (CPGQ) characteristic pain intensity (0–100) 38.7 (36.2–41.2) 41.5 (39.3–43.6) 0.110 −0.16 [− 0.34 to 0.03]
disability points (0–6) 1.6 (1.4–1.8) 2.0 (1.8–2.2) 0.025 −0.24 [− 0.43 to − 0.05]
 Health-related quality of life (SF-12) physical component (0–100) 43.3 (42.0–44.5) 41.0 (39.9–42.0) 0.007 0.26 [0.07 to 0.45]
mental component (0–100) 46.9 (45.5–48.3) 46.7 (45.5–48.0) 0.855 0.02 [−0.21 to 0.17]
Secondary outcomes
 Psychological distress (PHQ-4) sum score (0–12) 2.7 (2.4–3.1) 3.2 (2.9–3.4) 0.040 −0.24 [− 0.42 to − 0.05]
 Risk of chronifi-cation (STarT-G) total score (0–9) 2.6 (2.3–2.8) 3.0 (2.8–3.3) 0.009 − 0.25 [− 0.44 to − 0.07]
 Physical activitya days per week with at least 10 min physical activity (0–7) 2.7 (2.5–2.9) 2.4 (2.2–2.6) 0.028 0.21 [0.03 to 0.40]
  1. IG intervention group, CG Control group, p significance value; M+: values of the group means adjusted for baseline-score, StarT-G total risk score and satisfaction with medical care of back pain at baseline, CI Confidence interval; CPGQ Chronic Pain Grade Questionnaire; SF-12: Short Form 12; PHQ-4: Patient Health Questionnaire 4; STarT-G: Keele STarT back Screening Tool, German Version
  2. aphysically active in a way that one starts to sweat or gets out of breath
  3. Cohen’s d*: if higher scores of the outcome parameter describe worse health condition (e.g. GCPS-parameters), minus d means IG is superior to CG and plus d means IG is worse than CG; if higher scores describe better health conditions (e.g. SF-12 parameters), minus d signifies IG is inferior to CG and plus d means IG is better than CG