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Table 2 Change in efficacy outcomes including subjective somatic symptom burden and symptom preoccupation

From: A unified Internet-delivered exposure treatment for undifferentiated somatic symptom disorder: single-group prospective feasibility trial

Outcome Measure (theoretical range) Pre-treatment Post-treatment 3 months Change Pre-Post Change Pre-3MFU
   M SD n M SD n M SD n Slope (95% CI) Cohen’s dc Slope (95% CI) Cohen’s dc
Subjective somatic symptom burden PHQ-15 (0–30)ab 11.1 4.7 33 7.0 5.4 32 7.0 4.6 32  − 4.2 (− 5.5 to − 2.9) 0.90  − 4.2 (− 5.6 to − 2.8) 1.00
 Cardiopulmonary symptoms PHQ-15 subscale (0–2)a 0.7 0.5 33 0.4 0.4 32 0.4 0.3 32  − 0.3 (− 0.4 to − 0.2) 0.62  − 0.3 (− 0.4 to − 0.2) 0.65
 Fatigue symptoms PHQ-15 subscale (0–2)a 1.2 0.5 33 0.7 0.6 32 0.8 0.5 32  − 0.5 (− 0.7 to − 0.3) 0.75  − 0.3 (− 0.5 to − 0.2) 0.63
 Gastrointestinal symptoms PHQ-15 subscale (0–2)a 0.9 0.6 33 0.7 0.5 32 0.6 0.6 32  − 0.3 (− 0.5 to − 0.2) 0.56  − 0.3 (− 0.5 to − 0.2) 0.59
 Pain symptoms PHQ-15 subscale (0–2)ab 0.8 0.5 33 0.6 0.6 32 0.5 0.6 32  − 0.3 (− 0.4 to − 0.1) 0.44  − 0.3 (− 0.4 to − 0.1) 0.53
Symptom preoccupation SSD-12 (0–48)ab 30.7 9.2 33 18.4 12.5 32 18.5 10.5 32  − 13.0 (− 16.5 to − 9.4) 1.17  − 12.8 (− 16.5 to − 9.1) 1.32
 Anxiety sensitivity ASI-16 (0–64) 26.4 10.8 33 17.1 10.0 32 17.4 11.1 32  − 9.5 (− 13.1 to − 6.0) 0.89  − 9.2 (− 12.9 to − 5.6) 0.84
 Health anxiety HAI-14 (0–42) 25.5 6.8 33 18.8 8.6 32 18.4 9.2 32  − 6.7 (− 9.3 to − 4.2) 0.94  − 7.2 (− 9.7 to − 4.7) 0.95
General anxiety GAD-7 (0–21) 9.5 5.5 33 6.3 5.2 32 5.9 5.5 32  − 3.4 (− 5.0 to − 1.7) 0.73  − 3.7 (− 5.4 to − 2.1) 0.72
Depression symptoms PHQ-9 (0–27) 7.9 5.6 33 4.9 4.8 32 5.1 5.1 32  − 3.2 (− 4.6 to − 1.8) 0.70  − 2.9 (− 4.4 to − 1.5) 0.77
Overall functional impairment WD2-12 (0–100) 19.5 14.6 33 11.0 11.7 32 10.0 12.6 32  − 8.8 (− 13.0 to − 4.6) 0.70  − 9.8 (− 14.1 to − 5.6) 0.78
 Psychosocial impairment WD2-12 subscale (0–100) 23.8 15.4 33 14.3 12.8 32 13.3 13.8 32  − 9.7 (− 14.6 to − 4.9) 0.67  − 10.8 (− 15.6 to − 5.9) 0.75
 Mobility impairment WD2-12 subscale (0–100) 14.5 7.3 33 12.6 6.2 32 12.6 7.3 32  − 6.8 (− 10.9 to − 2.7) 0.59  − 8.4 (− 12.6 to − 4.3) 0.65
 Self-care impairment WD2-12 subscale (0–100) 32.1 16.9 33 25.6 11.5 32 24.0 12.9 32  − 1.9 (− 4.1 to 0.2) 0.32  − 2.0 (− 4.2 to 0.2) 0.29
Screening score of at least 1
 Cardiopulmonary symptoms PHQ-15 subscale (0–2)a 1.1 0.4 15 0.5 0.5 14 0.5 0.3 14  − 0.6 (− 0.8 to − 0.4) 1.16  − 0.5 (− 0.7 to − 0.3) 1.09
 Fatigue symptoms PHQ-15 subscale (0–2)a 1.3 0.4 25 0.8 0.6 25 0.9 0.5 25  − 0.5 (− 0.7 to − 0.3) 0.76  − 0.3 (− 0.6 to − 0.1) 0.61
 Gastrointestinal symptoms PHQ-15 subscale (0–2)a 1.2 0.4 18 0.9 0.4 18 0.9 0.6 18  − 0.4 (− 0.6 to − 0.1) 0.65  − 0.4 (− 0.6 to − 0.1) 0.68
 Pain symptoms PHQ-15 subscale (0–2)ab 1.2 0.4 17 0.7 0.7 17 0.8 0.6 17  − 0.4 (− 0.6 to − 0.2) 0.70  − 0.3 (− 0.6 to − 0.1) 0.63
  1. Intention-to-treat estimates based on piecewise linear mixed effects models with a spline at the post-treatment assessment. ASI-16 16-item Anxiety sensitivity index, 3MFU 3-month follow-up, HAI-14 14-item Health Anxiety Inventory, PHQ-9 Patient Health Questionnaire 9, PHQ-15 Patient Health Questionnaire 15 with subscales based on Witthöft et al. [49], SSD-12 Somatic Symptom Disorder 12, WD2-12 12-item World Health Organization Disability Assessment Schedule 2 with subscales based on Axelsson et al. [56]
  2. aAlso measured on a weekly basis after weeks 1–7 in treatment, so that change over the main phase could be modelled using data from 9 assessments. Phrasings of these questionnaires were changed so as to concern the past week
  3. bCurvilinear pattern of improvement as indicated by the fixed quadratic effect of main phase time improving model fit. For these outcomes, change scores for the Pre-Post main phase represent the sum of the time and time2 coefficients, and change for the Pre-3MFU period represent the sum of the time, time2 and follow-up-time coefficients
  4. cCohen’s d effect sizes calculated as the model-implied mean change divided by the observed standard deviation of change over the corresponding time period