Criteria abstracted from The Users' Guide to Medical Literature, from the Health Information Research Unit and Clinical Epidemiology and Biostatistics, McMaster University

Highlighted lines and questions below provide links to the pertinent description of criteria in The EBM User's Guide, now available at the Canadian Centres for Health Evidence

Article Reviewed:

Please visit the new Evidence Based Journal Club Reviews

Long-term Outcome of Children Surviving Massive Burns

Sheridan RL, Hinson MI, Liang MH, et al.

JAMA 2000;283:69-73. [abstract] [full-text for subcribers only]

Reviewed by Robert J. Graham MD, Children's Hospital, Boston

Review posted February 6, 2001

I. What is being studied?:

The study objective:

To investigate the long-term quality of life in children who have survived massive burns.

The study design:

Retrospective, cross-sectional study conducted in a regional pediatric burn center.

The outcomes assessed:

Quality of life (QOL) as determined by the Short Form 36 (SF-36) and the impact of clinical variables on domain scores within the SF-36.

II. Are the recommendations valid?

1. Have the investigators measured aspects of patients' lives that patients consider important?

Yes, the SF-36 addressed questions of global reintegration and socialization through its 8 domains: general health, physical functioning, social functioning, physical role, emotional role, mental health, energy/vitality, and bodily pain. This instrument was originally adapted from a 149-item Functioning and Well-Being Profile and the Medical Outcomes Study and has subsequently undergone extensive evaluation for reliability and validity (1).

2. Did the HRQL instrument work in the way it was supposed to?

The authors recognized that there are no widely accepted or validated quality of life instruments for burn patients. Thus, the SF-36 provided some clear advantages in its brevity and proven reliability and validity in assessing quality of life. Interestingly, the authors found health related quality of life (HRQL) to be equivalent between their cohort SF-36 responses and national norms, except in mental health which was surprisingly better in the study group. This speaks to either a profound, positive impact of the services provided or to the use of an unreliable tool in the SF-36. A recent study of HRQL instruments in cardiac patients found that the SF-36 lacked sensitivity in a disease-specific population (2), despite the fact that many of the SF-36 physical functioning domain questions focus on cardiac related quality of life. Signal to noise ratios for the SF-36 in the context of this study population may be too low. The authors report z-scores and p values when comparing to established norms. They noted large degrees of variability between patientsÕ HRQL scores; 15 and 20 percent of patients fell below 2 standard deviations of the norm in physical functioning and physical role domains, respectively, despite no overall difference with the general population. Significant findings upon subgroup analysis within the burn patient cohort, however, speaks to instrument responsiveness and validity.

3. Are there important aspects of HRQL that have been omitted?

Yes, several areas of HRQL were not evaluated due to limitations of the SF-36. Problems specific to burn patients, with or without inhalation injury, are not addressed including the potentially significant cosmetic changes. Second, there is no attempt to assess for the importance of age and disease interaction; e.g., mental health and social domains might have a greater relative importance during teenage years and effect reintegration following a massive burn injury. Third, the SF-36 does not factor in the utilization of medical or alternative therapies in any of the domains, whether medications, counseling, prostheses, or other resources. Fourth, measures of mental health cannot be extrapolated to actual psychiatric diagnoses as the SF-36 questions are limited to mental status within a 4 week time window and do not coincide with DSM-IV definitions. Lastly, serial use of the SF-36 in a longitudinal follow-up study rather than a cross-sectional outcomes study might be more informative. The use of a more comprehensive or, perhaps, less generic HRQL tool would be useful in future studies.

Interviews were limited to English speaking patients. Finding a tool validated in sufficient number of other languages was not necessarily feasible, but cultural and language differences could potentially have a significant impact on HRQL following severe burns. Future studies could also be expanded to assess QOL for care-givers as an index of impact on families.

If there were tradeoffs between quality and quantity of life, or and economic evaluation, have they used the right measure?

Economic impact was not an issue in this study as the Shriners Burn Hospital for Children offers comprehensive care at no cost. The authors, however, obtained extensive demographic information, including family structure, education, employment, as well as formal evaluation of the correlation between HRQL and the need for public assistance. Reintegration into routine activities was an important secondary index for societal impact; at the time of follow-up, 27 (36%) patients were fulltime student, 27 (36%) held regular employment, 6 (1%) were homemakers, 1 (1%) was incarcerated, and 12 (16%) were unemployed or received public assistance. Free, comprehensive services provided at Shriners, undoubtedly, facilitated access to care and follow-up and likely contributed to better outcomes.

III. What are the results?

1. What was the magnitude of the effect on HRQL?

The authors are to be applauded for their nearly complete cohort analysis, the care provided and the manner in which they present their findings. They reported that SF-36 domain scores of the study patients were similar to general US population. Nonparametric data analysis using Wilcoxon signed rank test revealed no differences between patients and established norms, except in the mental health domain which curiously favored patients with burns (median standardized score = 0.436, p =.02). The authors also provided the distribution of patient scores as a function of standard deviation from normative data. In the bodily pain domain the median standardized-score of burn patient were actually greater than the norm but the variable amongst burn patients, i.e., noise, contributed to a nonsignificant difference with the general population; depending upon the domain, 5 to 20 percent of patients were greater than two standard deviations below HRQL norms. While this data somewhat detracts from the magnitude of the effect of their care on HRQL it helps in the interpretation of the study.

Subgroup analyses, utilizing Mann-Whitney U test and the Spearman correlation coefficient, were also very informative. Not surprisingly, burn size correlated with poorer physical functioning and greater duration of time from injury correlated the improvements in emotional role domains. Younger patients demonstrated higher energy/vitality scores but scored lower in the emotional role. Gender differences were also found. Female patients scored higher in general health (p =.02), physical functioning (p =.02), and physical role (p =.001) , whereas males were higher on emotional role (p =.04). Consistent clinic visits, early reintegration into preburn activities and a family functional status correlated positively with most domain scores. These findings are probably of greater importance than the comparison to general population norms, as it identifies higher risk groups and potential areas for intervention.

The magnitude of the overall apparent positive effect on HRQL, however, can be questioned. The nature of a single site study limited the study sample and further subgroup analysis. Of the initial cohort, several patients were not included who may have altered the findings; one patient committed suicide and eight patients refused to respond, although their demographics were reportedly not significantly different. Parents also participated in the reporting of the eight children under 14 years of age and presumably with those diagnosed with mental retardation; inclusion of these groups poses some significant problems as there are no norms as well as potential for parental impact (3). The potential for chemical and substance abuse as a confounding variable was alluded to but not evaluated. Lastly, the authors neglected to mention any significant management changes during the treatment period, 1969-1992. This could be an additional area for stratification or comparison with other facilities in future studies.

IV. Will the recommendations help me in caring for my patients?

1. Will the information from the study help me inform my patients?

The authors recommend efforts to provide comprehensive care during the acute management and following discharge. This extends to family supports, community inclusion, and social services. Consistency and maximizing services through a multidisciplinary burn clinic can optimize quality of life despite potential for major cosmetic and functional limitations following massive childhood burns. Patients and their families in the acute recovery phase may find the prospects of a good QOL encouraging.

2. Did the study design simulate clinical practice?

Yes, recognizing the limitations of the quality of life measurement in this study, the conclusions are still compelling. The data refutes the assumption that children surviving severe burns have a poor quality of life. There is no comparison to QOL outcomes from other care facilities, but the authors alluded to the unique services offered at Shriners. Consolidation of resources would certainly facilitate comprehensive patient care efforts, including scar management, pulmonary follow-up, occupational and physical therapy, surgery and scar management, family and mental health services. This may, in turn, promote a better quality of life. More extensive quality of life assessments is still necessary.

References

1. Ware JE. The SF-36 health survey. http://www.sf-36.com/tools/sf36.shtml
2. Smith HJ, Taylor R, and Mitchell A. A comparison of four quality of life instruments in cardiac patients: SF-36, QLI, QLMI, and SEIQoL. Heart 2000; 84:390-394. [abstract]
3. Waters E et al. Influence of self-reported parent health on child health. Pediatrics 2000; 106(6):1422-1428. [abstract]

 

Comments

Back to the EB Journal Club Index