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

Hybelius, Jonna; Gustavsson, Anton; af Winklerfelt Hammarberg, Sandra; Toth-Pal, Eva; Johansson, Robert; Ljótsson, Brjánn; Axelsson, Erland

doi:10.1186/s40814-022-01105-0

Pilot and Feasibility Studies

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 d^c	Slope (95% CI)	Cohen’s d^c
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

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]
^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
^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
^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

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ISSN: 2055-5784

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