Personality Predicts Quality of Life in Pediatric Patients with Unintentional Injuries: A 1-Year Follow-up Study

Abstract

Objective Few studies have charted the course of health-related quality of life (HRQoL) in pediatric injury patients, and no studies so far have examined the extent to which variations in HRQoL 1 month and 1 year after injury are influenced by the child’s personality. Method One hundred and seven pediatric injury victims (6–14 years old) completed an interview on HRQoL and were rated on the personality domains of the Five-Factor Model by their mothers 1 month and 1 year after the incident. Results HRQoL was compromised after 1 month, particularly in the physical domain, but improved significantly after 1 year. Lower HRQoL after 1 month was predicted by female gender, injury severity, functional status, and neuroticism. After 1 year, lower HRQoL was predicted by concurrent functional status and neuroticism. Conclusions Even if HRQoL in children with unintentional injuries returns to normal levels after 1 year, significant variations remain, which are in part explained by personality.

Received May 27, 2004; revisions received September 6, 2004 and September 20, 2004; accepted October 12, 2004

In the Western world, major threats to child health are no longer infectious diseases, but unintentional injuries, which are the leading cause of death in children (Bockholdt & Schneider, 2003), with boys being particularly at risk (Schwebel, Speltz, Jones, & Bardina, 2002). In the case of nonfatal injuries, progress in surgical and other treatment techniques has minimized consequences of injury such as pains, scars, or reduced physical functioning. Still, injuries may compromise a child’s psychosocial adjustment as well as physical health in the short and long term. In the short term, many injuries cause considerable pain and discomfort, reduced mobility, and—in the case of traumatic brain injuries—problems with cognitive functioning. Moreover, there are indications that children may experience posttraumatic stress reactions because of injuries (Di Gallo, Barton, & Parry-Jones, 1997; Landolt, Vollrath, Ribi, Gnehm, & Sennhauser, 2003). In the long term, children have a remarkable ability to regain previous levels of functioning even after severe injuries (Schalamon, Bismarck, Schober, & Höllwarth, 2003). However, some children may continue to be handicapped by ongoing disability, pain, scars, or cognitive problems (Blakeney, Robert, & Meyer, 1998; Schwartz et al., 2003; Vladka, Poenaru, & Dueck, 2000).

How can we assess short- and long-term outcomes of injuries suffered by children? One of the most important approaches to gauging patients’ health outcomes is the assessment of health-related quality of life (HRQoL). HRQoL reflects a person’s subjective evaluation of the level of his or her functioning within the physical, emotional, cognitive, and social domains of health. HRQoL differs from medical evaluations of functioning, for it is based on the person’s own perceptions (Edwards, Patrick, & Topolski, 2003). In a stress and coping paradigm (Wallander & Varni, 1992), HRQoL results from a process of adaptation in which the person’s goals and beliefs, subjective illness interpretations, attributions, vulnerabilities, and coping skills play a role. Traditionally, HRQoL in children has been assessed by obtaining reports from proxies, such as parents or medical staff who have been in close contact with the child (Eiser & Morse, 2001a; Theunissen et al., 1998). However, given the subjectivity of HRQoL, the child’s own evaluation of his or her own health problems may be more accurate and valid (Theunissen et al., 1998), and an increasing number of studies rely on child self-report (Eiser & Morse, 2001a). This has to be weighed against the argument that children’s self-reports tend to be less accurate than those of adults, particularly as smaller children tend to forget quickly, are more influenced by momentary needs and states, and have a shorter attention span (Chambers & Johnston, 2002; Gordon, Baker-Ward, & Ornstein, 2001).

Prospective studies on HRQoL in pediatric patients with unintentional injuries are rare. Two retrospective studies suggest that HRQoL in injured patients returns to normal levels even if objective disabilities such as scars or functional disabilities remain. Landolt, Grubenmann, and Meuli (2002) had parents of burn patients report on their child’s HRQoL 1 to 13 years after the injury. Their results showed that the HRQoL of the former burn patients was not different from that of a group of healthy controls. This concurs with findings on young victims of road traffic accidents showing that HRQoL was only affected in the short term and returned to normal levels 2 years after the accident (Sturms, van der Sluis, Groothoff, ten Duis, & Eisma, 2003). However, retrospective studies cannot chart the course of HRQoL over time, nor can they show what factors truly predict improvements or deterioration in HRQoL.

To date, relatively little is known about these factors. Obviously, the type and severity of injuries can be expected to affect HRQoL (Schalamon, Bismarck, Schober, & Höllwarth, 2003). Particularly severe traumatic brain injury can result in permanent cognitive deficits (Schwartz et al., 2003; Stancin et al., 2002). In addition, psychological factors have been examined as predictors of HRQoL. For instance, better family relations were associated with better HRQoL in the study on pediatric patients mentioned above (Landolt et al., 2002). However, individual differences between children, such as temperament or personality, have until recently not been considered as predictors of HRQoL, even though they affect children’s adjustment in many ways (Shiner, 2000). Temperament traits refer to individual differences in emotions and behavior that appear early in life and that are presumed to have a biological basis (Rothbart, 1989). Personality traits capture dispositions to think, behave, and feel in certain consistent ways. They can be observed in children from the age of 4 years onward (Shiner, & Caspi, 2003). Just as in adults, children’s personality traits can be described in terms of the Five-Factor model (FFM), which constitutes the gold standard taxonomy in personality psychology today. The FFM comprises the broad personality factors of neuroticism, extraversion, agreeableness, conscientiousness, and openness to experience (De Fruyt & Vollrath, 2003; John & Srivastava, 1999; John, Caspi, Robins, Moffitt, & Stouthammer-Loeber, 1994; Mervielde & De Fruyt, 2002).

Although research on the impact of personality on HRQoL in children is virtually absent, the pertinent literature in adults shows substantial personality effects on HRQoL. In chronically ill adults, the most important predictor of—lower—HRQoL is neuroticism (Kempen, Jelicic, & Ormel, 1997; Kressin, Spiro, & Skinner, 2000; Penedo et al., 2003; Yamaoka et al., 1998). The relation of neuroticism with lower HRQoL probably results from the tendency on the part of persons high in neuroticism to experience negative mood and to focus on, recall, and report more symptoms of physical illness (Larsen, 1992; Smith, Pope, Rhodewalt, & Poulton, 1989). In addition, persons high in neuroticism tend to use dysfunctional coping when confronted with stress, which renders successful adaptation to ill health more difficult (Vollrath, 2001). Other important personality predictors of—higher—HRQoL are extraversion, a personality factor involving positive mood and sociability, and conscientiousness, a personality factor involving dependability and goal-directedness (Kempen et al., 1997; Penedo et al., 2003; Yamaoka et al., 1998). As far as children are concerned, the first and only study relating personality as framed by the FFM with HRQoL has only recently been published (De Clercq, De Fruyt, Koot, & Benoit, 2004). This study shows that HRQoL in pediatric cancer survivors was substantially predicted by neuroticism, benevolence (a childhood measure of agreeableness), conscientiousness, and imagination (a childhood measure of openness to experience).

There is little evidence today that children’s age and gender affect quality of life. Among 6- to 15-year-old Dutch children from the general population, gender and age differences were negligible (Vogels et al., 2000), and no gender differences were found in an overview of 12 studies among pediatric patients (Eiser & Morse, 2001b). However, Hoare, Mann, and Dunn (2000) found lower parent-rated HRQoL scores in boys as compared to girls across the diagnostic groups of diabetes and epilepsy.

The present prospective study is the first to examine effects of personality on HRQoL in children with unintentional injuries over time. The goals of the study are (a) to chart the course of HRQoL over 1 year’s time and (b) to examine the extent to which HRQOL is predicted by personality factors, after controlling for child characteristics and medical factors such as functional status and injury severity.

Methods

Participants and Procedure

Participants were 107 children and adolescents (aged 6–14.5 years) who were hospitalized for the treatment of an unintentional injury at four children’s hospitals in the German-speaking part of Switzerland. The ethical committees of the hospitals approved the study protocol. Inclusion criteria were (a) an unintentional injury (excluding severe head trauma), (b) age range from 6 to 16 years (adolescents older than 14.5 years participated in the study, but were excluded from the present analysis on account of the age limitation of the personality test), (c) sufficient command of the Swiss German or German language by the child and by his or her mother, (d) parents’ informed written consent to study participation, and (e) no evidence of prior mental retardation in the child. Further details on this sample were published previously (Vollrath, Landolt, & Ribi, 2003).

Over a period of 3 years, all patients fulfilling the selection criteria were contacted by the physician in charge of treatment, informed about the study, and asked to participate. Informed written consent was obtained from the parents of 138 patients (78% of 178 eligible families). Assessments were carried out approximately 1 month (M = 34 days, SD = 6) and 1 year after admission to the hospital. They consisted of a structured face-to-face interview with the injured patients, a questionnaire survey of the parents and the pediatricians, and information retrieved from hospital records. Most of the interviews (except for seven interviews at 1 month) were conducted in the patients’ homes by trained graduate students of psychology. One hundred and seven participants with interviews at both assessment points and at least one assessment of personality completed by the mother were included in the analysis (Table I). They represent 60% of the population of 178 eligible participants and 76% of those who participated at 1 month. Attrition was due to missing personality questionnaires, exclusion of patients older than 14.5 years (due to the age limitation of the personality test), and nonparticipation at the second assessment point. There were no differences between participants and nonparticipants with regard to gender or nationality (Swiss German and German nationals were lumped together and contrasted with nationals from other countries, for Germans speak the same language as Swiss Germans, and represent the best integrated group of foreign nationals in Switzerland). However, nonparticipants had more often injuries resulting from road traffic accidents, suggesting that some of the most severely injured children were not included. As expected, boys were overrepresented in this sample. Table I shows that nearly half of the children had suffered a fracture, eight of whom had multiple fractures. Duration of hospitalization ranged from 1 to 104 days (assessed at 1 year), with a mean of 10.6 days (SD = 14.1) and a median of 6 days.

Instruments

Medical Variables

A resident in pediatrics rated the severity of the injuries of all patients based on hospital records by using the Modified Injury Severity Scale (MISS). This is a highly reliable and widely accepted scale for rating injury severity (Mayer, Johnson, & Walker, 1980). The MISS allows the rating of the severity of single and multiple injuries in five different anatomical areas of the body. MISS values range from 0 to 75 (death), with 25 indicating a severe injury. Mean MISS score was 8.8 in this sample (SD = 7.3), with a range from 1 to 50. Five of the children had incurred severe injuries (MISS ≥ 25).

Information on functional status was obtained from the children’s physicians (the hospital pediatric surgeon at 1 month, and the child’s pediatrician at 1 year), who rated the child’s functional status by using two items. Item 1 described the patient’s degree of physical impairment, including bodily pain, and was rated on a 3-point Likert scale ranging from not impaired (0) to very impaired (2). Item 2 described the patient’s degree of functional impairment with respect to daily life (home, school, peers), and was rated on a 5-point Likert scale ranging from no effects (0) to strong effects (4). A mean score was computed after transforming the two scales to a common metric. Intercorrelations between the two items were r = 0.84 at 1 month and r = 0.82 at 1 year. Functional status ratings at 1 month correlated with functional status ratings at 1 year (r = 0.40, p = .001).

HRQoL

The data on HRQoL were collected by using the authorized German version of a short form of the TNOAZL [Toegepast Natuurwetenschappelijk Onderzoek—Academisch Ziekenhuis Leiden (Organisation for Applied Scientific Research-University Hospital Leiden)] Children’s Quality of Life (TACQOL) questionnaire, Child Form (Vogels et al., 2000), administered in a face-to-face interview with the child. This generic multidimensional questionnaire is a reliable and valid instrument for the assessment of self-reported HRQoL in children (Verrips et al., 1998). It covers the domains of bodily, cognitive, emotional, and social functioning.

The short form of the TACQOL included the original seven scales, but used only four items per scale instead of eight for all scales except one (body). Items were selected by A.C.G. Vogels based on the best item-total correlations in the normative Dutch sample ( Vogels et al., 2000). The seven scales are (a) physical complaints (body), assessing common bodily complaints (e.g., headache, stomach aches, nausea) (this scale retained all eight items of the original version), (b) motor functioning (motor), assessing locomotion functioning (e.g., walking, running); (c) autonomy (auto), assessing independent functioning (e.g., going to the bathroom, eating without help), (d) cognitive functioning (cognit) (e.g., concentration, understanding schoolwork), (e) social functioning (social), assessing interactions with peers (playing or interacting, being included in the group), (f) positive emotions (emopos) such as excitement and joy, (g) negative emotions (emoneg), such as happiness, sadness, or anger.

Following the TACQOL protocol, children were first asked whether a specific problem or symptom had occurred during the 2 weeks before the interview. If affirmed, the child was requested to rate his or her emotional response to the problem. Answer choices were: problem never occurred (4), or, if the problem occurred, I felt well (3), I did not feel so well (2), I felt rather bad (1), I felt bad (0). The two scales on positive and negative emotions were scored on a scale from 0 to 2 (often [2], sometimes [1], never [0]). The scores of the emoneg scale were reversed. On all TACQOL scales, higher scores signify better quality of life. The TACQOL scales showed acceptable internal consistency coefficients, except for the body and social scales (Table II). It was not possible to improve the internal consistency of the scales by removing items. Scale distributions were skewed, as is to be expected from this type of measure. A normalization of the scales by any of the usual transformations (square root, logarithm) was not possible.

The TACQOL scales showed low to medium intercorrelations at 1 month, ranging from r = −0.01 (between the scales auto and emoneg) to a maximum of r = 0.52 (between motor and auto), with a mean scale inter-correlation of r = 0.28. At 1 year, intercorrelations varied between r = −0.10 (between social and auto), and .55 (between auto and motor), with a mean scale intercorrelation of r = 0.15. These low to moderate intercorrelations correspond with findings from the normative Dutch sample (Vogels et al., 2000), and from Dutch pediatric patients (Vogels et al., 1998), confirming that the scales tap different aspects of HRQoL. To obtain a reliable measure of overall quality of life, we also computed a composite score by summing the items across all scales (except for the items of the social scale) after recoding them to a common metric. Thereby, all scales contributed to the sum score with equal weight. The distribution of the composite score was a skewed at 1 month, but a normal at 1 year (Kolmogorov-Smirnov Goodness of Fit test).

Hierarchical Personality Inventory for Children

The Hierarchical Personality Inventory for Children (HiPIC) is a 144-item observer-based inventory for the assessment of the Big Five trait domains in children (De Fruyt & Mervielde, 1998; Mervielde & Asendorpf, 2000; Mervielde & De Fruyt, 1999). It covers the trait domains extraversion, benevolence (corresponding to agreeableness), neuroticism, conscientiousness, and imagination (corresponding to openness to experience). The five domain scores are composed of 18 facets or subscales. Each HiPIC item refers to a particular overt behavior and is formulated in the third-person singular without negations. Items were rated on a five-point Likert scale ranging from uncharacteristic (1) to very characteristic (5). In this study, mothers were the informants on their child’s personality. The HiPIC ratings were carried out by the mothers at both assessment points and sent in by mail. Instructions required mothers to describe their child’s personality as observed during the year before the injury at 1 month and during the year after the injury at 1 year. An authorized German version of the HiPIC was used (De Fruyt & Vollrath, 2003), and it showed good internal consistency of the facets and domain scores in this sample (Vollrath et al., 2003). One-year stability coefficients of the five domain scales were very high, except for the neuroticism scale: extraversion, r = 0.83; benevolence, r = 0.87, conscientiousness, r = 0.84, neuroticism, r = 0.69, imagination, r = 0.81). To increase the reliability and validity of the personality measurement, average HiPIC domain scores were computed across the two assessment points. This attenuates potential bias in mothers’ personality ratings that may have been present immediately after the injury. The intercorrelations between the domain scores varied between r = 0.08 (Benevolence and Imagination) and r = 0.48 (Imagination and Conscientiousness).

Socioeconomic status (SES) was calculated by means of a six-point score of both paternal occupation and maternal education, and ranged between 2 and 12 points. Three social classes were defined: SES score 2–5, lower social class; SES scores 6–8, middle social class; and SES scores 9–12, upper social class. This measure was used in previous studies and was shown to be a reliable and valid indicator of SES (Largo, Molinari, Comenale Pinto, Weber, & Duc, 1986).

Statistics

Because the TACQOL scales showed nonnormal distributions, nonparametric statistical techniques were used where possible (Wilcoxon tests for pair-wise comparisons over time, Spearman-Brown rank correlations to calculate associations). The HiPIC domain scores were normally distributed according to the Kolmogorov-Smirnov Goodness of Fit test. In the multiple regression analyses, only the composite TACQOL scores were used as dependents, because they showed higher reliability, and a distribution that was closer to normality. Variables assessing personal and medical characteristics were forced into the equations in Step 1, and personality scores were entered stepwise in Step 2, using a forward stepwise procedure (p of entry = .05). For the regression analysis, the extremely skewed MISS score was dichotomized at the 75th percentile (12 points), thereby making it possible to test more severe injuries against light or moderate injuries.

Results

Quality of Life at 1 Month and 1 Year

Table II shows mean TACQOL scores at 1 month and 1 year, lists Cronbach’s alphas, and gives the stability coefficients of the scales across 1 year. In addition, the table provides comparison values basing on the data from the Dutch normative sample (Vogels et al., 2000) that were calculated with the reduced item of our short form (A.C.G. Vogels, personal communication, May 2004). The control sample comprised 861 healthy children (children with chronic diseases were excluded), of which 49.5% were boys and 50.5% girls, ranging in age between 8 and 11 years. At 1 month, the injured children showed lower scores on the motor, auto, and emopos scales and a higher score on the body scale compared with the Dutch control group. This indicates reduced HRQoL in the physical domain, particularly with regard to motor activity, which is little surprising given that half of the injured children had fractures. Interestingly, physical HRQoL was not affected; indeed, our participants had higher scores on the body scale than the comparison sample. Presumably, the rather diffuse physical complaints such as headache tapped by this scale did not adequately represent the localized pains and discomforts experienced by the injured children. In sum, the lowered composite score in the injured children indicated reduced HRQoL, but the effect size was modest (Cohen’s d = 0.25).

At 1 year, the injured children showed higher scores on the body and social scales and lower scores on the emopos scale than the Dutch control sample. The composite score did not differ from the composite score of the control group at 1 year, suggesting a “normalized” HRQoL in our participants. More importantly, the prospective comparison showed a significant improvement of HRQoL scores in the injured children 1 year on, with massive improvements in the domains of motor activity and autonomy, modest improvements in the domains of cognitive and social functioning, and no improvement in the domain of emotions. Stability scores of the TACQOL scales were low to moderate, as is expected for a measure assessing fluctuating states. It is interesting that the composite score showed relatively high stability (r = 0.52), which suggests a dispositional aspect of HRQoL.

Table III reveals a range of correlations between the personal characteristics of the patients, medical variables, and TACQOL scores at 1 month and 1 year. Correlations between age and the TACQOL scales were negligible at both time points, except for the social scale. More importantly, gender showed many correlations with the TACQOL scales at both time points, with girls reporting lower HRQoL than boys. The lower HRQoL scores in girls could not be explained by greater injury severity, as their MISS score (Wilcoxon rank test: z = −0.1843, p = .85) and functional status scores did not differ from boys’ scores (z = −0.31, p = .19 at 1 month, and z = −0.41, p = .68 at 1 year). Socioeconomic status showed correlations with single TACQOL scales at 1 month and 1 year, but did not correlate with the composite TACQOL score. Interestingly, the MISS injury severity score correlated with the TACQOL scales at 1 month, but failed to do so at 1 year, indicating that initial medical injury severity is unrelated to subjective quality of life in the long term. In contrast, concurrent physician-rated functional status correlated with the children’s HRQoL quite well. This is not entirely surprising, as functional status’ ratings tap the same domain of functioning as HRQoL, that is, quality of life. Because of the wide age range of the sample, correlations of the personal and medical variables with the TACQOL scores were compared for children above (n = 46) and below the age of 10 years (n = 61). Fisher’s r to z transformation was used to determine whether differences between deviating scores were significant. None of the correlations differed between the two age groups.

Table IV shows correlations between averaged HiPIC personality scores and TACQOL scores. Neuroticism showed the most correlations with the TACQOL scores at both assessment points. At 1 month, neuroticism correlated negatively with motor, cognit, and the composite score. Conscientiousness and Imagination correlated positively with the cognit scale. At the 1-year follow-up, correlations between personality scores and TACQOL scores were more frequent and more elevated. Neuroticism correlated negatively with the physical domain scales, body, motor, auto, the emoneg scale, and the composite score. Benevolence and Conscientiousness correlated positively with emoneg, and the composite score. Again, separate analyses were carried out for children below and above the age of 10 years, and the size and direction of correlation coefficients was inspected and tested by means of r to z transformations. However, no significant difference could be revealed.

Table V shows the multiple regression equations of the TACQOL composite scores. At 1 month, female gender, the dichotomized MISS score, and functional status together explained 17% of the variance of the TACQOL composite score. Neuroticism explained an additional 7% of the variance in Step 2, thus ranging on an equal level with gender and functional status as predictors. At 1 year, the strongest predictor of the TACQOL composite score was the corresponding score at 1 month, showing that HRQoL was remarkably stable. Gender did not predict HRQoL after 1 year, presumably because the gender effect was mediated by the effect of the TACQOL composite score at 1 month. This interpretation is supported by the finding that gender predicted the TACQOL composite at 1 year nearly significantly (β = .15, p = .09) if the 1 month composite was not controlled for. Concurrent functional status ratings were better predictors of the TACQOL composite score than the MISS score. Neuroticism added significant variance to the equation, improving the total explained variance by 6%. This finding shows that neuroticism not only depresses initial HRQoL—which in turn predicts later HRQoL—but also reduces improvement of HRQoL over time.

Discussion

The aim of this study was to chart the HRQoL of children and adolescents with unintentional injuries 1 month and 1 year after the incident, and to examine the impact of personality, personal characteristics, and medical variables on their HRQoL.

The comparison of the participants’ HRQoL with those of the Dutch reference group indicated that HRQoL was markedly compromised after 1 month, particularly in the domain of physical functioning. After 1 year, HRQoL was essentially “back to normal” in comparison with the Dutch sample.

Injury severity predicted subjective HRQoL to a modest extent only at 1 month and not at all at 1 year. These findings suggest that injured children can experience good HRQoL irrespective of initial injury severity. It could be argued, though, that the children’s self-reported HRQoL scores lack validity. However, the substantial correlations between self-reported HRQoL and the concurrent physicians’ ratings of functional status contradict this arguement. In addition, correlations between HRQoL and medical or personality variables did not interact with age. Finally, the relatively high stability of HRQoL over 1 year suggests that the children’s responses were reliable and consistent.

An unexpected finding was the substantial correlation between female gender and poorer initial HRQoL. At the same time, gender did not affect the course of HRQoL after 1 year over and above this initial effect. It could be speculated that girls are more reactive, in the short term, to the functional restrictions and bodily pains resulting from an acute injury than boys, but that their adjustment over time functions equally well. This interpretation would be in line with findings on equal levels of HRQoL in boys and girls with chronic diseases (Eiser & Morse, 2001a; Hoare et al., 2000), who had a long period of time to adjust to their condition.

The main finding of our study was that HRQoL in injured children is affected by personality, after controlling for age, gender, and — most importantly — injury severity and functional status. Firstly, HRQoL was relatively stable over 1 year, suggesting the notion of a dispositional core of quality of life. This matches research on well-being in adults showing that well-being is very stable (Diener, Suh, Lucas, & Smith, 1999). Secondly, as hypothesized, personality affected HRQoL after controlling for medical variables, particularly the basic factors of neuroticism, conscientiousness, and benevolence. The effect of neuroticism was twofold. High neuroticism predicted poorer HRQoL initially, and it also reduced HRQoL improvements after 1 year. The negative effects of neuroticism on HRQoL correspond with previous findings on adults (Kempen et al., 1997; Kitamura et al., 2002), and concur with the findings on pediatric cancer survivors reported by De Clercq (2004). They could be explained by the negative perception bias that is typical for neuroticism (Larsen, 1992), as well as by ineffective, passive ways of coping with life events (Vollrath, 2001). The effects of benevolence and conscientiousness in the bivariate analysis indicated that children who are pleasant, social, perseverant, and task-oriented find it easier to adjust to their health condition. Several mechanisms could explain this relation, not the least superior coping skills in children scoring high on these traits, as well as greater willingness in adults and peers to support the child. However, the conscientiousness and benevolence effects did not survive the multiple regression equations, probably due to their overlap with neuroticism.

This study has a number of limitations that need to be addressed. Most importantly, the age range of the children in this sample was wide, which was a concern with respect to the reliability and validity of the HRQoL assessments, particularly in the younger children. However, there were no age effects on HRQoL, nor did age interact with the personal, medical, and personality variables that affected HRQoL. At the same time, we may not have had the statistical power to detect interaction effects. The dilemma of a wide age range is pervasive in studies on pediatric patients because the conditions targeted tend to be infrequent, particularly if only recent-onset conditions are included. Even for our less than perfect sample, a 4-year assessment period at four children hospitals was necessary. Lower reliability in HRQoL increases the chance of overlooking relations with other variables. On the other hand, reliance on child-reported HRQoL offered important advantages as well, for shared method variance between personality and HRQoL measures was avoided. The decision to rely on child-reported HRQoL made it necessary to exclude children with severe brain injuries. Hence, our findings regarding the course of HRQoL over time cannot be extended to that group of patients. Moreover, the comparison of the TACQOL scores with those of the Dutch control group must be interpreted with caution. Cultural differences, translation problems, age differences (the Dutch children were between 8 and 11 years old), and procedural differences (personal interviews in our sample, paper and pencil tests in the Dutch sample) may compromise comparability.

In spite of these limitations, our findings suggest that children with light to moderately severe injuries suffer reduced HRQoL 1 month after the incident, but show a positive development with significant improvements after 1 year. Risk factors for poorer HRQoL 1 year on are poor initial HRQoL, poor functional status, and elevated scores on the personality factor of neuroticism. In addition, girls reported lower HRQoL initially. In consequence, it may be fruitful to target interventions to children who show low initial HRQoL, particularly if they are girls and show signs of anxiousness and low self-esteem, which are indicative of neuroticism.

Acknowledgment

Margarete Vollrath, University of Oslo, Institute of Psychology, Oslo, Norway; Markus A. Landolt, University Children’s Hospital Zurich, Steinwiesstrasse 75, 8032 Zurich, Switzerland. This research was funded by grants from the Gebert-Ruef Foundation, the Hugo and Elsa Isler Foundation, and the Anna Mueller-Grocholski Foundation. The authors are grateful to the families that participated in this project, the graduate students who interviewed the children, and to all the participating physicians. We extend our thanks to Felix H. Sennhauser and Hanspeter E. Gnehm, both heads of Pediatric Hospitals, for their invaluable support and their contributions to this study. Ellen Russon (www.ellenrusson.com) and Karoline Vollrath are thanked for stylistic corrections. Moreover, we acknowledgment the thorough and encouraging comments of the two anonymous reviewers.

References

Author notes

¹University of Oslo and ²University Children’s Hospital