Fear avoidance and return to work after mild traumatic brain injury

Figures & data

Figure 1. Included participants from studies one and two (n = 175).

Table 1. Demographic and clinical characteristics of the two study samples (n = 175).

Variable	Study 1 (n = 85)	Study 2 (n = 90)
Demographic characteristics
Age [(years), mean (SD)]	37.0 (14.8)	36.5 (12.8)
Sex [male, n (%)]	34 (40.0)	28 (31.1)
Ethnicity [n (%)]
- New Zealand Māori	7 (8.2)	8 (8.9)
- Non New Zealand Māori	78 (91.8)	82 (91.4)
Highest education level [n (%)]
- High school or less	33 (38.8)	29 (32.2)
- University/Tertiary	52 (61.2)	61 (67.8)
Previous mild traumatic brain injury [yes, n (%)]	48 (56.5)	35 (38.9)
Previous mental health history [yes, n (%)]	50 (59.5)	46 (51.1)
Injury and Clinical Characteristics
Mechanism of Injury [n (%)]
- Transport-related	28 (32.9)	9 (10.0)
- Fall	25 (29.4)	43 (47.8)
- Assault	9 (10.6)	5 (5.6)
- Hit by Object	9 (10.6)	33 (36.7)
- Other	14 (16.5)	0 (0.0)
Symptoms at time 1 [T1 RPQ Total, mean (SD)]	29.9 (13.7)	29.2 (13.6)
Psychological distress at time 1 [T1 DASS-21 Total, mean (SD)]	16.9 (11.0)	20.0 (13.0)
Time from injury to assessment at time 1 (T1) [weeks, mean (SD)]	6.5 (2.6)	6.5 (2.7)
Time from injury to assessment at time 2 (T2) [weeks, mean (SD)]	30.6 (4.2)	32.9 (3.2)

T1 = Time 1 = (6.5 weeks after injury); T2 = Time 2 (31.8 weeks after injury); FA = fear avoidance, RPQ = Rivermead Post Concussion Symptoms Questionnaire; DASS-21 = Depression, Anxiety, and Stress Scale.

Table 2. Demographic and clinical characteristics of the study sample by patterns of fear avoidance behavior after traumatic brain injury (FAB-TBI) scores at times 1 and 2 (n = 175).

	Patterns of fear avoidance between times 1 and 2
Variable	Low-Low (n = 50)	Low-High (n = 24)	High-Low (n = 23)	High-High (n = 59)
Demographic characteristics
Age [(years), mean (SD)]	37.9 (14.3)	38.9 (13.1)	30.4 (11.3)	37.4 (13.7)
Sex [male, n (%)]	17 (34.0)	7 (29.2)	6 (26.1)	25 (42.4)
Ethnicity [n (%)]
- New Zealand Māori	4 (8.0)	2 (8.3)	2 (8.7)	2 (8.7)
- Non New Zealand Māori	46 (92.0)	22 (91.7)	21 (91.3)	22 (93.2)
Highest education level [n (%)]
- High school or less	10 (20.0)	5 (20.8)	9 (39.1)	29 (49.2)
- University/Tertiary	40 (80.0)	19 (79.2)	14 (60.9)	30 (50.8)
Previous traumatic brain injury [yes, n (%)]	26 (52.0)	9 (37.5)	7 (30.4)	28 (47.5)
Previous mental health history [yes, n (%)]	23 (46.0)	14 (56.5)	13 (60.3)	35 (58.3)
Injury and Clinical Characteristics
Mechanism of Injury [n (%)]
- Transport-related	11 (22.0)	9 (37.5)	0 (0.0)	14 (23.7)
- Fall	21 (42.0)	7 (29.2)	7 (30.4)	24 (40.7)
- Assault	2 (4.0)	2 (8.3)	3 (13.0)	5 (8.5)
- Hit by Object	12 (24.0)	5 (20.8)	10 (43.5)	12 (20.3)
- Other	4 (8.0)	1 (4.2)	3 (13.0)	4 (6.8)
Symptoms at baseline [T1 RPQ Total, mean (SD)]	22.0 (13.7)	31.3 (11.8)	32.9 (9.4)	35.8 (10.6)
Psychological distress at baseline [T1 DASS-21 Total, mean (SD)]	12.1 (9.1)	19.9 (9.7)	17.6 (10.8)	25.0 (12.8)

T1 = Time 1 = (6.5 weeks after injury); T2 = Time 2 (31.8 weeks after injury); FA = fear avoidance, RPQ = Rivermead Post Concussion Symptoms Questionnaire; DASS-21 = Depression, Anxiety, and Stress Scale, Fear avoidance measured with FAB-TBI = Fear Avoidance Behavior after Traumatic Brain Injury Questionnaire interval score; Time 1 Low FAB-TBI scores: 0.0–22.6, High FAB-TBI scores: 23.1–48.0; Time 2 Low FAB-TBI scores 0.0–17.4, High FAB-TBI scores 18.4–48.0.

Table 3. Baseline variables and return to work related activity 6–9 months after mild traumatic brain injury (n = 175).

	N	RTW T2 (yes, n %)	Unadjusted OR	95% CI
Time 1 Fear avoidance (FAB-TBI), per 5 unit change			0.75	0.56–0.99
Gender
- Male	54	38 (70.4)	1.67	0.89–3.14
- Female	99	55 (55.6)	Ref.
Age at injury
− 16–25 years	34	29 (85.3)	6.78	2.22–20.68
− 26–35 years	52	33 (63.5)	3.39	1.23–9.38
− 36–45 years	25	12 (48.0)	2.06	0.65–6.54
− 46 − 55 years	19	9 (47.3)	1.93	0.57–5.59
− 56–70 years	23	7 (30.4)	Ref.
Ethnicity
- Non-Māori	141	86 (61.0)	1.33	0.46–3.83
- Māori	12	7 (58.3)	Ref.
Education
- High school or less	54	33 (61.1)	1.00	0.53–1.85
- Tertiary/University	99	60 (60.6)	Ref.
Mental health history
- Yes	84	49 (58.3)	0.81	0.44–1.47
- No	69	44 (63.8)	Ref.
Previous concussion
- Yes	68	39 (57.4)	0.63	0.34–1.24
- No	85	54 (63.5)	Ref.
Time 1 Symptom burden (RPQ), per 6 unit change			0.84	0.73–0.97
Time 1 Psychological distress (DASS-21), per 6 unit change			0.86	0.73–1.01

Dependent variable = return to usual levels of work-related activity (RTW) at time 2 (T2); OR = Odds ratio; CI = Confidence Interval; FAB-TBI = Fear Avoidance Behavior after Traumatic Brain Injury Questionnaire (total interval score); RPQ = Rivermead Post-Concussion Symptom Questionnaire (total score); DASS-21 = Depression, Anxiety, and Stress Scale (total score).

Figure 2. Fear avoidance scores between times 1 and 2, showing mean of the difference (middle line) and 95% agreement limits. (A larger positive difference means greater improvement in fear avoidance. FAB-TBI = Fear Avoidance Behavior after Traumatic Brain Injury questionnaire; RTW = return to usual levels of work-related activity 6–9 months after mild traumatic brain injury).

Figure 3. Frequency bar graph of return to work-related activity by patterns of fear avoidance between times 1 and 2. (RTW = return to usual levels of work-related activity).