Patterns of post-traumatic stress symptoms in mild traumatic brain injury and their relationship with outcomes: a latent profile analysis

Figures & data

Table 1. Participant characteristics.

Demographic Characteristics	Baseline (N = 252)	Six Month Assessment (N = 187)	P value
Age [Mean (SD, range)]	37.02 (14.17, 17–76)	37.53 (14.15, 17–76)	.171
Sex (female) [N (%)]	160 (63.5%)	122 (65.2%)	.705
Ethnicity [N(%)] – NZ European – Other	170 (67.5%) 82 (32.5%)	132 (70.6%) 55 (29.4%)	.040
Education – n with post-secondary school qualification [N(%)]	163 (64.7%)	122 (65.2%)	.904
Pre-Injury Employment Status [N(%)] – Working – Not working	185 (73.4%) 67 (26.6%)	155 (82.9%) 32 (17.1%)	.019
Prior Mental Health History (yes) [N(%)]	135 (53.6%)	100 (53.5%)	.984
Prior Concussion History (yes) [N(%)] Pre-injury Medical Diagnosis (yes) [N(%)]	112 (44.4%) 99 (39.3%)	82 (43.9%) 80 (42.8%)	.901 .461
Clinical Characteristics
Time Since Injury (weeks) [Mean (SD, range)]	6.29 (2.48, 2.0–12.0)	31.59 (3.37, 24.0–42.0)
Mechanism of Injury			.284
– Transport accident	38 (15.1%)	26 (13.9%)
– Fall	90 (35.7%)	66 (35.3%)
– Assault	23 (9.1%)	15 (8.0%)
– Head versus object	101 (40.1%)	80 (42.8%)
Other Injury Sustained (yes) [N(%)]	137 (54.4%)	104 (55.6%)	.795

Figure 1. Mean PTSS cluster scores in the three latent profiles.

Table 2. Model Fit Information Determining Number of Latent Class.

Profiles	AIC	BIC	SSABIC	Entropy	VLMRA (p value)	BLRT
1	5087.50	5108.77	5089.75	-	-	-
2	4663.84	4699.29	4667.58	0.923	<.001	<.001
3	4506.18	4555.81	4511.43	0.892	0.154	<.001
4	4398.55	4462.36	4405.30	0.914	0.012	<.001
5	4367.72	4445.71	4375.96	0.929	0.149	<.001
6	4342.71	4434.88	4352.46	0.933	0.096	<.001

Note. AIC = Akaike Information Criteria; BIC = Bayesian Information Criteria; SABIC = sample size adjusted BIC; VLMRA = Lo-Mendell-Rubin adjusted likelihood ratio test, BLRT = Bootstrapped likelihood ratio test. Optimal model in bold.

Table 3. Multinomial regression analysis for the latent classes of PTSS.

	B	SE	Exp(B)	95%CI	p
Moderate
Age	−0.01	0.01	1.00	0.98–1.02	.942
Gender	0.15	0.33	1.16	0.61–2.20	.657
Education	−0.24	0.31	0.78	0.41–1.50	.461
Pre-Injury Work	0.64	0.36	1.90	0.95–3.82	.070
Medical History	−0.02	0.33	1.00	0.53–1.87	.998
Concussion History	−0.12	0.31	0.89	0.48–1.64	.701
Mental Health History	−0.28	0.31	0.75	0.41–1.38	.363
Mechanism of Injury	1.35	1.46	3.84	1.89–7.84	<.001**
Other Injury	−0.11	0.31	0.90	0.49–1.65	.728
Moderate with High Int/Av
Age	−0.01	0.02	1.00	0.97–1.02	.773
Gender	−0.64	0.41	0.53	0.23–1.18	.121
Education	−0.44	0.43	0.64	0.28–1.48	.299
Pre-Injury Work	0.69	0.46	1.99	0.81–4.85	.132
Medical History	−0.39	0.44	0.68	0.29–1.60	.377
Concussion History	0.05	0.42	1.05	0.47–2.40	.861
Mental Health History	0.07	0.41	1.08	0.48–2.40	.674
Mechanism of Injury	1.52	0.41	4.57	2.06–10.11	<.001**
Other Injury	−0.61	0.42	0.54	0.24–1.24	.146
Highly Symptomatic
Age	0.01	0.51	1.00	0.96–1.06	.709
Gender	1.25	0.76	3.48	0.78–15.36	.100
Education	−1.69	0.73	0.19	0.04–0.78	.021*
Pre-Injury Work	2.08	0.68	8.00	2.12–30.15	.002**
Medical History	0.45	0.75	1.57	0.36–6.83	.549
Concussion History	−0.35	0.68	0.71	0.19–2.67	.606
Mental health History	−0.31	0.69	0.74	0.19–2.84	.657
Mechanism of Injury	1.97	0.51	7.16	2.62–19.61	<.001*
Other Injury	−2.65	`.09	0.07	0.01–0.60	.015**

^aReference group is the low symptom class.

** p < .05, * p < .01,

Referred to: male, post-secondary school education, working before mTBI, no medical history, no mental health history, no concussion history, mechanism of injury: accidental (head versus object, fall), did not sustain another injury when the mTBI occurred

Table 4. Comparison of mTBI outcomes at baseline and at six-month follow-up between each latent profiles of PTSS.

		Mean difference	Std. Error	95% CI	p
Post Concussion Symptoms at Baseline	Resilient vs.
	Moderate	−5.67	1.63	−10.02 – −1.36	.003
	Moderate High Int/Av	−7.76	2.23	−13.68 – −1.84	.003
	Highly Symptomatic	−9.60	3.61	−19.19 – .001	.050
	Moderate vs.
	Moderate High Int/Av	−2.07	2.12	−7.72–3.57	1.00
	Highly Symptomatic	−3.91	3.34	12.80–4.99	1.00
	Moderate High Int/Av vs
	Highly Symptomatic	−1.83	3.41	−10.91–7.24	1.00
Post Concussion Symptoms at Six Month Follow-Up	Resilient vs.
	Moderate	−4.04	1.65	−8.43–0.35	.091
	Moderate High Int/Av	−6.99	2.21	−12.89 – −1.10	.011
	Highly Symptomatic	−13.30	3.59	−22.88 – −3.73	.002
	Moderate vs.
	Moderate High Int/Av	−2.95	2.35	−9.22–3.32	1.00
	Highly Symptomatic	−9.26	3.65	−19.00–0.47	.072
	Moderate High Int/Av vs.
	Highly Symptomatic
		−6.31	3.94	−16.83–4.21	.668
Functional Status at Six Month Follow-Up	Resilient vs.
	Moderate	−2.60	1.12	−5.59 -. 390	.129
	Moderate High Int/Av	−5.47	1.51	−9.49- −1.45	.002
	Highly Symptomatic	−9.64	2.45	−16.17 – −3.12	<.001
	Moderate vs.
	Moderate Int/Av	−2.87	1.60	−7.14–1.40	.449
	Highly Symptomatic	−7.04	2.49	−13.67 – −0.47	.031
	Moderate High Int/Av vs
	Highly Symptomatic	−4.17	2.69	−11.34–3.00	.734