Long-term risk factors for impaired burn-specific health and unemployment in patients with thermal injury

1. Introduction 

Increased survival rates in patients receiving burn care over the past few decades have led to an increase in attention to rehabilitation and factors that influence outcome [1], [2], [3]. Compared with general population norms, most burn patients adjust rather well [4], [5], [6], [7], but significant impairments of various aspects of outcome have been demonstrated, especially in subgroups of patients who experience certain levels of physical or psychological burden because of their injury [5], [7], [8], [9], [10], [11].

Self-rated health is influenced by a multitude of factors [12], [13], and when predictors of burn patient health status are studied, the use of a disease-specific measure may be of special value because of its increased sensitivity to the problems impacted by the injury, the treatment and their consequences [12], [14]. The burn-specific health scale (BSHS) was developed in the 1980s as a self-reporting questionnaire, determining burn patients’ physical and psychological health and their post-injury adjustment [15], [16]. Although appearing in different versions, it is still the only disease-specific questionnaire for measuring health status in burn patients. Using this instrument, significant associations between the extent of total body surface area (TBSA) burn [17], [18], full-thickness injury (FTI) [18], [19], [20], [21], the number of surgical interventions and the length of hospitalization [17], [20], [22], and patient health status were demonstrated. Moreover, pre- and post-burn psychological disorders [17], [23], neurotic personality traits [24], extensive use of avoidant coping [25], as well as pain [17], [26] seem to be associated with impaired burn-specific health. Finally, better adjustment has been reported among male patients [19], [22], those who were married [19] and those who were employed at the time of the query [17], [19], [20], [23], [27].

Even though the work status of burn patients is still an under-studied research topic, it is well documented that burn patients may have significant problems returning to their pre-burn jobs [27], [28], [29], [30], [31]. Moreover, burn patients seem to have lower employment rates than the general population [7]. Several factors have been related to return to work, such as the extent of burn [29], [32], the presence of hand burns [32], the length of hospitalization [29], a history of psychiatric disorder [29], [31], [33], the type of work [32] and the employment status at the time of injury [28], [30], [33]. In addition, patient subjective assessment of functional ability, appearance, pain and generic health status has been found to correlate with work status after burn [7], [27], [29].

When studying adjustment, the timing of assessment seems to influence the results significantly, and in two recent studies, the relative importance of the factors influencing burn patient outcome has been demonstrated to change during the first year after injury [11], [26]. At present, only a few studies on burn-specific health [18], [19], [21], [22] and work status [27], [29], [30], [31] have an observational time of more than 1 year. Thus, there is still little information regarding long-term risk factors and their relative importance for patients’ burn-specific health and employment status.

The purposes of this study were: first, to identify self-reported socio-demographic factors and co-morbidities, as well as injury-specific factors that could predict long-term impaired physical and psychosocial burn-specific health; second, to estimate the explanatory strength of these factors; and third, to determine risk factors for long-term post-burn unemployment. We hypothesized that socio-demographic factors and co-morbidity are as important for long-term burn-specific health and work status as most injury-related factors.

2. Materials and methods 

2.3. Patients 

All patients aged 18 years or more hospitalized for burn injury at the national Burn Center, Haukeland University Hospital, Bergen, from 1995 to 2000 were included. Of 162 patients still living at the time of the enquiry, those known not to be fluent in Norwegian (n=10) and those with severe brain damage (n=1) or dementia (n=2) were excluded. Six patients could not be located, resulting in a total sample of 143 patients.

Ninety-five patients answered the questionnaires (response rate 66.4%; Table 1). Seventy-eight of the responders were men, and the mean age was 43.7 years. The mean TBSA burn was 18.5%, and mean FTI was 7.4%. The most frequent cause of injury was flame burn. Thirty-five (36.8%) and 14 (14.7%) patients had a physical and psychological illness, respectively. In addition, 17 patients (17.9%) reported chronic pain.

Table 1. Patient characteristics

		N	%	Mean (S.D.)
	Demographics
	Age (years)			43.7 (14.5)
	Sex (M/F)	78/17	82/18
	Living alone	25	26
	Housing or economic problems	11	12
	Education ≤12 years	82	86
	Unemployeda	19	20
	Self-reported illnesses
	Physical illness	35	37
	Psychological illness	14	15
	Chronic pain	17	18
	Burn characteristics
	Flame burn	56	59
	Scald burn	23	24
	Electrical burn	13	14
	Contact burn	3	3
	TBSAb burn (%)			18.5 (14.2)
	FTIc (%)			7.4 (9.3)
	FTIc face (yes)	5	5
	FTIc hands (yes)	35	37
	FTIc feet (yes)	10	11
	Deformitiesd	7	7
	Inhalation injury	9	10
	Number of operations			1.8 (2.0)
	Length of hospital stay (days)			23.2 (21.0)

a Unemployed means out of work, receiving social security and being less than 67 years of age. b Total body surface area. c Full-thickness injury. d Deformities were defined as partial or total loss of the nose, ears, fingers, toes, external genitalia or limbs.

When comparing responders and non-responders, no significant differences were demonstrated with regard to any of the socio-demographic and clinical factors tested [7].

3. Results 

3.1. BSHS-N scale scores 

The overall mean patient self-reported burn-specific health as measured by the BSHS-N total scale score was 85.1% of the possible maximum score (Table 2). The BSHS-N domain with the lowest mean score (81.3%) was the general health domain, whereas role activities had the lowest mean score of all subdomains (73.8%) (Table 2).

Table 2. Burn-specific health status assessed by the BSHS-N questionnaire

	BSHS-N domains	All patientsa (n=94)	Employeda,b (n=68)	Unemployeda,b,c (n=19)
	Physical health	88.8 (15.3)	93.1 (13.0)	76.5 (14.6)‡
	Mobility and self-care (items 1–10)	94.0 (13.1)	96.3 (12.2)	87.9 (12.4)‡
	Hand function (items 11–15)	93.2 (15.9)	96.6 (12.4)	82.9 (22.7)†
	Role activities (items 16–20)	73.8 (27.6)	82.8 (22.7)	47.4 (22.6)‡
	Mental health	83.8 (17.4)	87.7 (14.4)	67.2 (20.1)‡
	Body image (items 21–27)	86.0 (18.9)	89.4 (15.4)	69.5 (23.9)‡
	Affective (items 28–50)	83.1 (18.6)	87.2 (15.6)	66.5 (21.6)‡
	Social health	86.9 (15.3)	91.7 (10.8)	71.9 (19.0)‡
	Family and friends (items 51–62)	87.5 (16.2)	92.2 (10.9)	70.7 (21.1)‡
	Sexual activity (items 63–65)	84.6 (22.5)	89.6 (18.2)	76.8 (23.8)*
	General health (items 66–80)	81.3 (16.7)	84.9 (14.6)	67.0 (18.0)‡
	Total score (items 1–80)	85.1 (14.5)	89.2 (11.8)	70.4 (15.2)‡

a Scale scores are given as means (S.D.). b Employed means working and being less than 67 years of age; unemployed means out of work, receiving social security and being less than 67 years of age. c Significance of difference between scale scores in employed and unemployed patients determined by the Mann–Whitney exact test; *P<0.05; †P<0.01; ‡P<0.001.

3.2. Predictors of reduced BSHS-N scale score 

Based on clinical and conceptual considerations, multiple correlation analyses between potential covariates (not shown), and correlations between socio-demographic or clinical factors and BSHS-N scale scores (Table 3), the factors included in the regression model were chosen as age, gender, living alone, psychological illness, chronic pain, extent of FTI, and presence of FTI involving face, hands or feet.

Table 3. Correlations between burn-specific health status and socio-demographic and clinical factors

		BSHS-N domainsa
		Mobility and self-care	Hand function	Role activities	Body image	Affective	Family and friends	Sexual activity	General health	Total score
	Age	−0.226*	−0.159	−0.268†	−0.004	0.057	−0.067	−0.265†	0.034	−0.026
	Female sex	−0.347†	−0.309	−0.283†	−0.175	−0.237*	−0.146	−0.275†	−0.198	−0.255*
	Living alone	−0.357‡	−0.302†	−0.320†	−0.220*	−0.268†	−0.211*	−0.308†	−0.240*	−0.302†
	Housing or economical problems	−0.143	−0.090	−0.229*	−0.267†	−0.297†	−0.319†	−0.291†	−0.259†	−0.308†
	Physical illness	−0.273†	−0.127	−0.215†	−0.117	−0.113	−0.211*	−0.158	−0.122	−0.156
	Psychological illness	−0.271†	−0.178	−0.337†	−0.358‡	−0.474‡	−0.409‡	−0.298†	−0.411‡	−0.460‡
	Chronic pain	−0.433‡	−0.259*	−0.370‡	−0.320†	−0.376‡	−0.339†	−0.224*	−0.352†	−0.399‡
	TBSAb burn (%)	−0.134	−0.007	−0.155	−0.333†	−0.081	0.008	−0.128	−0.153	−0.122
	FTIc (%)	−0.377‡	−0.269†	−0.330†	−0.495‡	−0.254*	−0.206*	−0.387‡	−0.351†	−0.355†
	FTIc face (yes)	−0.170	−0.295†	−0.177	−0.219*	−0.222*	−0.241*	−0.264*	−0.258*	−0.247*
	FTIc hands (yes)	−0.077	−0.194	−0.108	−0.260*	−0.036	−0.044	0.027	−0.133	−0.087
	FTIc feet (yes)	−0.298†	−0.155	−0.289†	−0.139	−0.145	−0.163	−0.131	−0.183	−0.226*
	Deformities	−0.198	−0.337†	−0.193	−0.170	−0.071	−0.088	−0.026	−0.026	−0.117
	Inhalation injury	−0.091	−0.236*	−0.016	−0.301†	−0.100	−0.182	−0.103	−0.182	−0.149
	Number of operations	−0.505‡	−0.445‡	−0.408‡	−0.462‡	−0.291†	−0.259*	−0.303†	−0.425‡	−0.403‡
	Length of hospital stay	−0.408‡	−0.299†	−0.399‡	−0.522‡	−0.340†	−0.244*	−0.418‡	−0.486‡	−0.448‡

a Spearman correlations; *P<0.05; †P<0.01; ‡P<0.001. b Total body surface area. c Full-thickness injury.

Multivariate analyses demonstrated that these factors explained 57% of the variance in the BSHS-N total scale score (Table 4). In addition, from 59% of the variance in the role activities subdomain to 33% of the variance in the sexual activity subdomain could be explained (Table 4). Chronic pain significantly impaired the scores in all subdomains of the BSHS-N except sexual activity, with the greatest reduction observed in role activities (29%; Table 4). Psychological illness also had a major impact on the patients’ experience of their subjective health, with significantly reduced scores in all subdomains except mobility and self-care and hand function. Of the injury-specific factors chosen to be included in the model, FTI affecting the face or feet had significant impact on the patients’ health scores (Table 4). The extent of FTI per se did not induce significant alterations in the patients’ health perception in this model (Table 4).

Table 4. Predictors of burn-specific health statusa

		Age	Female sex	Living alone	Psychological illness	Chronic pain	FTIb (%)	FTIb face (yes)	FTIb hands (yes)	FTIb feet (yes)	R2
	Mobility and self-care
	Regression coefficient	0.034	−6.300	−8.744	−5.955	−8.219	−0.182	−6.932	2.613	−13.263	0.459
	P	0.665	0.047	0.002	0.069	0.004	0.244	0.178	0.306	<0.001
	Hand function
	Regression coefficient	0.022	−10.050	−6.387	−6.307	−12.728	−0.119	−8.449	−5.676	−6.413	0.359
	P	0.831	0.018	0.081	0.147	0.001	0.564	0.218	0.097	0.168
	Role activities
	Regression coefficient	−0.393	−12.652	−8.746	−23.881	−29.201	−0.013	−19.368	−6.428	−24.843	0.590
	P	0.008	0.029	0.081	<0.001	<0.001	0.965	0.041	0.169	<0.001
	Body image
	Regression coefficient	−0.050	1.273	−0.957	−16.239	−17.060	−0.256	−12.205	−8.654	−5.796	0.343
	P	0.688	0.798	0.825	0.002	<0.001	0.300	0.136	0.035	0.238
	Affective
	Regression coefficient	0.056	−4.248	−6.389	−27.480	−14.556	0.221	−11.726	1.135	−5.432	0.499
	P	0.591	0.306	0.079	<0.001	<0.001	0.283	0.086	0.736	0.238
	Family and friends
	Regression coefficient	−0.076	1.209	−4.750	−23.867	−12.037	0.320	−14.401	−0.574	−5.581	0.436
	P	0.448	0.759	0.168	<0.001	0.001	0.105	0.028	0.858	0.204
	Sexual activity
	Regression coefficient	−0.475	−5.903	−8.327	−16.143	−4.883	−0.224	−14.525	0.988	−4.761	0.327
	P	0.002	0.330	0.115	0.012	0.370	0.455	0.144	0.841	0.478
	General health
	Regression coefficient	0.047	−5.273	−4.656	−16.409	−14.679	0.015	−17.352	−3.738	−10.168	0.430
	P	0.653	0.202	0.195	<0.001	<0.001	0.942	0.011	0.266	0.028
	Total score
	Regression coefficient	−0.028	−4.339	−5.867	−19.218	−14.066	0.053	−12.996	−1.607	−8.596	0.573
	P	0.719	0.160	0.030	<0.001	<0.001	0.730	0.011	0.521	0.013

a Multiple linear regression; n=90. b Full-thickness injury.

3.3. Work status 

Patients who were unemployed reported significantly lower BSHS-N total scale scores (70.4%) than those who were employed (89.2%; Table 2). In addition, the scores of patients not working were reduced in all subdomains, with the lowest score (47.4%) in the role activities subdomain (Table 2). Unemployment was significantly associated with housing or economic problems, chronic pain, extent of FTI, presence of deformities, number of operations, and length of hospital stay (Table 5).

Table 5. Patient socio-demographic and clinical risk factors associated with employment status

	Risk factors	Employeda	N	Mean (S.D.)	Test statistics	P
	Age (years)	Yes	69	40.4 (11.8)	t: −1.220	0.232b
		No	19	43.8 (10.3)
	TBSAc burn (%)	Yes	69	18.3 (14.7)	z: −1.446	0.150d
		No	19	22.2 (13.1)
	FTIe (%)	Yes	67	6.5 (9.5)	z: −2.782	0.005d
		No	19	10.6 (9.4)
	Number of operations	Yes	69	1.5 (2.0)	z: −3.106	0.001d
		No	19	2.7 (1.9)
	Length of hospital stay	Yes	69	20.9 (21.6)	z: −2.400	0.016d
		No	19	30.7 (18.9)

	Risk factors	Employeda	N	Percentage with risk factor	Test statistics (χ2)	P
	Female sex	Yes	9	13.0	3.620	0.083f
		No	6	31.6
	Living alone	Yes	15	21.7	1.812	0.232f
		No	7	36.8
	Housing or economic problems	Yes	4	5.8	13.128	0.001f
		No	7	36.8
	Physical illness	Yes	20	29.0	3.707	0.062f
		No	10	52.6
	Psychological illness	Yes	8	11.6	4.448	0.069f
		No	6	31.6
	Chronic pain	Yes	7	10.1	13.876	0.001f
		No	9	47.4
	FTIe face (Yes)	Yes	2	2.9	1.998	0.202f
		No	2	10.5
	FTIe hands (Yes)	Yes	24	34.8	1.007	0.423f
		No	9	47.4
	FTIe feet (Yes)	Yes	7	10.1	0.471	0.445f
		No	3	15.8
	Deformities	Yes	3	4.3	5.678	0.037f
		No	4	21.1
	Inhalation injury	Yes	5	7.4	3.005	0.100f
		No	4	21.1

a Employed (n=69) means working and being less than 67 years of age; unemployed (n=19) means out of work, receiving social security and being less than 67 years of age. b t-test. c Total body surface area. d Mann–Whitney exact test. e Full-thickness injury. f χ2-exact test.

Of the 69 patients employed at the time of query, 57 answered questions on their current work. Thirty-one (54%) reported that they had the same job as before the injury, and 17 (30%) had a better job, whereas 8 (14%) had the same job as before but with different work or reduced time at work. Only one patient (2%) reported undertaking part-time odd jobs for pay.

4. Discussion 

This study demonstrated that, at an average of 47 months after being burned, the injury still interfered significantly with patient health status and work. Consistent with our hypothesis, factors of socio-demography, non-burn-related morbidity and the burn itself impaired burn patient psychosocial and physical health and employment status significantly.

Activities demanding physical strength or social interaction beyond the household level, such as sports activities and work (see the scores in the BSHS-N subdomain role activities) were particularly affected. Self-care activities such as bathing, eating and dressing (mobility and self-care, and hand function) were much less impaired. Moreover, the general health domain had the lowest domain score, with itching, intrusive memories and feelings of lack of energy being the single items representing the largest patient challenge. The BSHS-N scale scores in this study are largely consistent with those of others using burn-specific health as a long-term outcome [19], [22], indicating that more complex functioning (role activities) and post-burn symptoms, of both physical and psychological nature, are the most troublesome sequelae of burn.

Although much effort has been made to study the impact of burn on the lives of survivors, there is still no consensus on risk factors associated with long-term impaired health and functioning, and few studies with an observational time of more than 1 year have been reported [18], [19], [21], [22]. We constructed a multivariate regression model, and by including selected factors of socio-demography, non-burn-related morbidity and the burn injury itself, 57% of the total variance in long-term burn-specific health as measured by the BSHS-N could be explained.

Chronic pain was one of the major contributors to impaired physical and psychosocial health status in this study, and the burn patients’ performance of complex roles was most negatively affected by chronic pain. After the first post-discharge year, the prevalence of burn-related pain has been reported to be stable [36], [37], and persistent pain may be a problem in up to 50% of patients with severe burn [37]. In their retrospective study of 236 burn patients, Malenfant et al. observed that, even though 80% of burn patients characterized their chronic pain as mild or moderate, 47% reported that their social activities were disturbed because of pain [36]. In addition, chronic pain may interfere with rehabilitation, sleep, concentration and activities of daily life [36], [37]. Cromes et al. suggested earlier that by 6–12 months after injury, pain is no longer a predictor of reduced burn-specific health [26]. On the contrary, our findings indicate that chronic pain continues to be a significant challenge to burn-specific health as well as the generic health of burn patients up to 47 months post-hospitalization [7]. Even though our study could not document the origin or nature of patient self-reported chronic pain, these findings suggest that increased knowledge and long-term attention to pharmacological or behavioural strategies to relieve burn patients from chronic pain are needed.

In this study, psychological illness predicted impaired burn-specific health significantly, affecting both the total score and the scores of all psychosocial BSHS-N subdomains. The lowest scores were observed in the affective subdomain, which mainly asks for unpleasant feelings and states of mood. Notably, psychological illness also impacted significantly on the role activities subdomain, indicating that the patients reported problems in household chores, leisure-time activities and work. Blalock et al. [17] and Cromes et al. [26], reporting on the burn-specific health adjustment the first year post-burn, found that anxiety, depression and emotional distress predicted reduced BSHS scores. Because increased rates of psychiatric disorders, as well as post-injury stress, anxiety and depression, have been demonstrated in burn patient populations [1], [7], [38], [39], high-quality psychological support and treatment may be of special value for the optimal long-term psychosocial rehabilitation of many burn patients.

In their long-term follow up study, Kildal et al. reported that living with a partner and having one's own residence were related to better burn-specific health outcome [19]. We also found that social factors, such as living alone or having housing or economic problems, correlated with reduced burn-specific health status. However, using multivariate analyses, living alone only affected the subdomain mobility and self-care and the total score of BSHS-N, suggesting that the practical implications of burn for self-care and mobility were the most troublesome for those living alone.

Full-thickness injury, the number of operations and the length of hospital stay correlated negatively with burn-specific health status. Even though similar observations have been made by others [19], [21], [22], only the localization of FTI could predict burn-specific health in this study. Facial FTI significantly increased the feelings of difficulty in performing complex roles such as leisure-time activities (role activities subdomain), reduced perceived well being in social interactions (family and friends subdomain) and impaired patient perception of health (general health) in multivariate analyses. These findings suggest that facial FTI creates disadvantages for social re-integration and a propensity for withdrawn leisure-time activity [10]. Moreover, FTI affecting the feet was a significant predictor of impaired physical and general health in our study. This indicates a possible long-term functional limitation related to decreased standing or walking endurance [40]. Full-thickness hand injury had an impact on body image only in univariate and multivariate analyses, suggesting that patients experienced this more as an aesthetic problem than a functional one.

Successful community integration of adult burn patients includes enabling them to return to work. In our study, 20% of working-aged patients were unemployed 47 months post-injury, with significantly lower scores in all BSHS-N domains. The patient work rate was significantly lower than in the general population [7], and chronic pain was the strongest risk factor for unemployment. Dyster-Aas et al. reported significantly more problems with pain in non-working patients than among those employed at follow-up, approximately 9 years after injury [27]. The physical activity and temperature variation of many types of work may trigger discomfort and pain in the healed wounds [36], [37], thereby interfering with employment status. This suggests that effective prevention and management of pain may increase the long-term employment rates for burn patients. During rehabilitation to work, the influence of co-morbidity has to be taken into consideration, and psychiatric problems in particular have been reported to be a major determinant for not returning to work up to 2 years after injury [31], [33]. In this study, the proportion of patients having concomitant physical illness or psychological illness was greater in the unemployed group than in the employed group, although this difference did not reach statistical significance.

Both TBSA burn and FTI have been indicated as significant risk factors for delayed return to work after burn injuries [30], [41]. However, Saffle et al. demonstrated that the number of operations and the length of hospitalization, factors that are expressions of the seriousness of the injury and the patient's need for and response to treatment, were even better correlated with time off work than TBSA burn or FTI [29]. We found here that FTI, the number of operations, the length of hospitalization and the presence of deformities, but not the extent of TBSA burn, were significantly associated with decreased employment rate 47 months post-injury.

This study was to some degree limited by its cross-sectional, retrospective design and its sample size, which put restrictions on the number of factors to be included in the multivariate testing of health status and precluded multivariate testing of work status. However, the data available allowed for construction of a multivariate model including selected factors of socio-demography, non-burn-related morbidity and the burn itself that explained 57% of the total variance in long-term burn-specific health. Moreover, long-term burn-specific health and work status could be studied in the same patient cohort.

In summary, factors of socio-demography, non-burn-related morbidity and the burn itself significantly impaired burn patients’ psychosocial and physical health and work status. The nature of the risk factors identified demonstrate the importance of assessing the perceived well being of patients, and support the further development of broad and long-term rehabilitation programs.