Development of Disease-Specific Health-Related Quality-of-Life Instruments for Children With Immune Thrombocytopenic Purpura and Their Parents

Abstract

Purpose 

Immune thrombopenic purpura (ITP) is an important childhood hematologic disorder that is often frightening to patients and their parents because of its acute onset and bleeding symptoms. There is no consensus on the management of ITP in children. Pediatric hematologists have differing management philosophies, yet most, explicitly or implicitly, incorporate into their management approach the potential impact on the child's and family's quality of life. There is no validated ITP-specific health-related quality-of-life instrument for use with children with ITP, nor is there one to evaluate the burden experienced by their parents. ITP is usually a self-limited disorder. With current controversy over management approaches, an evaluation of the disease burden experienced by the child and the family may assist with the assessment of alternative treatment approaches.

Methods 

Using standard clinimetric methodology, 88 children with acute or chronic ITP, along with their parents, participated in the development of the instruments.

Results 

The 26-item ITP-Child Quality-of-Life Questionnaire includes five domains: treatment side effect-related, intervention-related, disease-related, activity-related, and family-related. This instrument can be used as a self-completed instrument for most children older than 7 years or as a proxy-completed instrument by parents of children younger than 7 years. The 26-item ITP-Parental Burden Quality-of-Life Questionnaire includes six domains: concerns related to diagnosis/investigation, treatment/disease monitoring, monitoring of child's activities, interference with daily life, disease outcome, and emotional impacts.

Conclusions 

The first steps of the development of these formally developed instruments are complete. The instruments are available for study to validate and test their responsiveness through use in clinical research studies. Such instruments are increasingly recognized as important for comprehensive measurement of patient outcomes in this and other areas of pediatric hematology/oncology practice.

Considerations involving the health-related quality of life of the child with immune thrombocytopenic purpura (idiopathic thrombocytopenic purpura; ITP) and that of the child's parents have the potential to influence treatment decisions. As there is no established standard approach to the treatment of ITP (¹), management decisions can be modified based on individual child and family needs. Although it is a relatively common childhood disorder, with an estimated annual incidence of 4 per 100,000 children (²), ITP is not a disease with which the general public is familiar. For more than 80% of children with ITP, the disorder is an acute self-limiting illness occurring in previously healthy young children, usually between the ages of 2 to 5 years. There is, however, a small but real risk of intracranial bleeding (²) and, for the 20% of children with chronic ITP, the ongoing threat of a serious bleed. Recognized management approaches include expectant treatment (no medications unless bleeding is severe), corticosteroids, intravenous gamma globulin, and intravenous anti-D (^1–7). The long-term outcomes from these interventions are equivalent, although in the short term the platelet count may recover more quickly with gamma globulin, anti-D, or high-dose corticosteroids than with expectant treatment (³). Other interventions may include bone marrow aspiration and hospitalization (^2–8). Factors that may adversely affect the child's and family's quality of life include anxiety while the child is thrombocytopenic, complications of treatment, duration of treatment, need for invasive interventions, and costs or inconvenience of the treatment. Each approach to treatment has advantages and disadvantages, with differing impacts specific for each patient and family.

Despite an increasing awareness of the need for emphasis on factors other than the platelet count (effect on quality of life, degree of bleeding symptoms, cost/adverse effects of treatment) (^2,9), there are no published, validated disease-specific health-related quality-of-life instruments for children with ITP or for their parents. In 1997, the Canadian Children's Platelet Study Group (¹⁰) began developing the disease-specific health-related quality-of-life instruments described in this article. See Appendix for the resulting instruments. The instrument for children with ITP was designed in self-assessment and proxy-assessment formats. These formally developed instruments now require validation and assessment of responsiveness within clinical research trials related to the care of children with ITP.

METHODS

Children from 1 to 17 years of age with acute or chronic ITP with a platelet count less than 150 × 10⁹/L and their parents were recruited by pediatric hematologists in eight centers in Canada and two centers in the United States. Chronic ITP was defined as thrombocytopenia persisting for greater than 6 months. Children with secondary ITP (associated with immune deficiency, collagen vascular disorder, or other cause) were not eligible for the study. To eliminate the chance of including children with undiagnosed congenital thrombocytopenia, infants less than 1 year of age were not eligible for this study.

To develop these evaluative questionnaires, we followed the guidelines outlined by Townsend et al. (¹¹), Guyatt et al. (¹²), and Juniper et al. (¹³) for both the development of the instrument for children with ITP and the instrument for their parents. The development included the following: generation of an extensive list of items of potential importance to children with ITP and a separate list of items important to their parents (phase I questionnaire and literature search); determination of the frequency and importance of these items (phase II questionnaire); and rank-ordering of the most frequent and important (burdensome) items (phase III questionnaire development). The aim was to develop instruments in which the choice of items reflected the interests and concerns expressed by children with ITP and the interests and concerns expressed by their parents, ease of self-administration, brevity, and suitability for simple scoring (¹³).

A total of 88 children and 90 parents (16 fathers) were entered on study. After obtaining informed consent, children with acute ITP and their parents (45 parents; 7 fathers) were interviewed within 7 days of diagnosis of ITP or at the 3-month (median) follow-up visit. Of the 43 children with acute ITP, 15 were interviewed within 7 days of initial diagnosis. Forty-five children with chronic ITP and 45 parents (9 fathers) participated in the study. Proxy responses were obtained from 90 parents (74 mothers and 16 fathers). Thirteen children with acute ITP had a platelet count of less than 20 × 10⁹/L; 4 had a platelet count of 20 to 50 × 10⁹/L; and 26 had a platelet count of more than 50 × 10⁹/L at the time of completion of the phase II instrument. Fourteen children with chronic ITP had a platelet count of less than 20 × 10⁹/L; 17 had a platelet count of 20–50 × 10⁹/L; and 14 had a platelet count of more than 50 × 10⁹/L). The median age of children with acute ITP was 4 years (mean 4.8 years, range 1.5–13.3); for children with chronic ITP the median age was 10.2 years (mean 10.2 years, range 4–16). The children were treated per individual pediatric hematologist preference and ranged from children treated expectantly at home to children hospitalized and treated with intravenous gamma globulin. This patient population was thought to reflect the spectrum of childhood ITP, thus ensuring that the instruments developed would be relevant to all stages of the disease.

Standard clinimetric methodology (the determination of a broad base of items that together reflect the health-related quality of life impacts of the illness and treatment on the population under study) was used to develop the instrument. Clinimetric methodology has been formally defined as the use of indexes, rating scales, and other measures applied to describe symptoms, physical signs, or other clinical phenomena related to specific clinical entities (¹⁴). Using this method, potential items were identified from the literature and from interviews with children, parents, and health care professionals (phase I). The literature review was supplemented with potential items of concern identified through a semistructured phase I questionnaire completed by Canadian pediatric health care professionals (pediatric hematologists, hematology nurses, social workers) familiar with the care of children with ITP. Similar questionnaires were completed by parents of children with acute or chronic ITP, as well as children older than 7 years with acute or chronic ITP. The questionnaire listed headings of physical, emotional, and social changes for the children with ITP. For the parents of children with ITP, the headings were functional changes (things that changed the daily routine for parents/family), emotional/social changes (things that changed relationships or feelings), and added costs (costs incurred because the family included a child with ITP). Fifteen health care professionals and 50 parents and 7 children with ITP completed the phase I semistructured questionnaire.

Another group of children and parents rated the items according to frequency and importance (bother) (phase II). Items that were not relevant to an individual were marked as nonapplicable and were not included in the calculation of the mean response score. Items that were frequently endorsed, as well as items respondents classified as particularly burdensome, were retained for the phase III instrument.

A 78-stem-question phase II instrument for children with ITP (138 total questions [one item per question]) was generated from the input obtained. The items of concern identified for parental burden were used to construct a 92-stem general questionnaire (184 total questions, one item per question). In addition, there was a 16-stem-question in strument for parents of children with chronic ITP and an 18-stem-question instrument for parents of children with acute ITP. A five-point Likert scale was used in the interviewer-administrated phase II instruments. The questions were designed to capture the frequency and burden or “botherment” of each item identified in phase I. A sample question was, a) “Did you have to change what activities you could do?” 0. Hardly at all; 1. A little; 2. Some; 3. A lot; 4. Very, very often; b) “Did this bother you?” 0. Hardly at all; 1. A little; 2. Some; 3. A lot; 4. Very, very much. For some questions (for example, “Did you find it stressful that your child had to have a bone marrow test?”), the question was preceded by the question, “Did your child have a bone marrow test? If no, skip to Question 92” to ensure that questions were answered only when relevant. Few applicable questions were not answered by participants, and those were mainly due to time constraints.

The response data were entered into an Oracle database; statistical analyses were performed with SAS version 8. A mean response score (MRS; an arithmetic mean) for each question was calculated from the numeric average of the scores from each question (using the total number of responses as the denominator). Potential scores ranged from 0 (least burden) to 4 (greatest burden). Copies of the phase II questionnaires are available from the first author.

The questions were grouped into domains to allow an overview of specific areas of health-related quality-of-life impact. These domains were determined by reviewing the questions for logical groupings and degree of correlation among items.

RESULTS

Seven English Canadian centers, one French Canadian center, and two centers in the United States took part in the interviews using the phase II questionnaire. The proxy phase II questionnaire was administered by trained interviewers to 90 parents: 45 were parents of children with acute ITP and 45 were parents of children with chronic ITP. Three proxies for children were completed by both parents of children with acute ITP, as were two proxies by both parents of children with chronic ITP. For one child with acute ITP and two children with chronic ITP, a proxy questionnaire was not completed. A self-assessment was available for 50 children (15 children with acute ITP and 35 children with chronic ITP). Matched child–proxy questionnaires were available for 41 children. Parents were interviewed separately from their child. A parental burden questionnaire was not available for three children. When both parents were interviewed (five sets), their interviews were conducted separately. The phase II forms took approximately 30 minutes to complete for the children's burden and 60 to 90 minutes for the parents' burden. The trained interviewers did not explore the participant responses but did clarify the questions when requested to do so by participants.

The phase II questionnaire assessed concerns from a population that reflected the spectrum of age, severity, and chronicity of childhood ITP. The core group of authors (D.B., M.W., D.F., V.B.) were responsible for data analysis and the final choice of items to be included in the phase III instruments. The final choices were determined through group discussion.

Parental Burden Instrument

For the development of the phase III parental burden instrument, items with an MRS of 2.0 or greater were identified. This yielded 22 stem questions from the general parental burden phase II instrument, 10 from the acute ITP parental burden instrument, and 5 from the chronic ITP parental burden instrument, for a total of 37 questions. These 37 questions were examined for degree of correlation with other questions using SAS version 8.0, Pearson correlation coefficient. The item–item correlation analysis helped to determine if any of the identified high-burden questions could be eliminated from the phase III questionnaire because they overlapped significantly with other items. The correlations observed helped to identify questions with related domains or areas of concern. In the phase II questionnaire, several questions that were similar in content were intentionally included to examine the consistency of answers by respondents. Three groups of closely related, high-burden questions emerged: those dealing with concerns about the potential complications of gamma globulin or anti-D (4 questions), those dealing with concerns about whether the child with ITP could have a serious illness such as leukemia or cancer (4 questions), and those dealing with watching the child to prevent injury (2 questions). Within the grouped questions, these questions were highly correlated (P < 0.0001, correlation coefficient >0.5) and appeared to be addressing similar concerns. One question from each category was chosen for the phase III instrument. A further question, “Were you worried?” was eliminated. Although the responses indicated a high burden, the specific worries appeared to be covered adequately in the remaining questions. Eliminating questions that were duplicated in the general, acute, and/or chronic phase II instruments left 22 questions. The wording of the question chosen was felt to reflect most clearly the concern expressed.

Further analyses of subgroups were performed. Subanalyses of the chronic ITP group added concerns about limiting the child's activities, waiting for test results, and treatments requiring an intravenous infusion. The question “Did your child miss time from school?” had an MRS score of 2.0, but “Did this bother you?” had an MRS score of 0.9 and was not included in the phase III instrument. For the acute ITP group, an additional concern about comfort leaving the child with a sitter was identified. The concerns about limiting activities, comfort with leaving the child with a sitter, and requiring an intravenous treatment were added, resulting in 25 questions. Parents of children whose platelet count was less than 20,000 found waiting for test results stressful, and this question was added to the instrument. No further questions were identified through subgroup analyses; thus, the phase III instrument has 26 questions.

The responses to the phase II instrument were completely reviewed to ensure that the final questions chosen had face validity (assessed the concern addressed in the question), content validity (sampled all the relevant or important content or domains), were clearly stated, reflected parental burden rather than burden to the child with ITP, and had the potential to be responsive to changes in the child's ITP. Although there were several areas with greater burden for either parents of children with acute ITP (feeling had to be constantly watching out for the child, MRS acute 2.48 vs. 1.79 for chronic) or for parents of children with chronic ITP (worry about side effects from treatment, MRS acute 1.79 vs. 2.63 for chronic), the questions in the final phase III instrument were felt to reflect concerns of both parents of a child with acute ITP and parents of a child with chronic ITP.

The domains in the phase III parental burden instrument were determined by reviewing the questions for logical groupings and by degree of correlation among items. The six domains are diagnosis/investigation concerns (^1,5,20,21, 26); treatment/disease monitoring concerns (^6,10,11,14,24); monitoring the child's activities (^7,8,9,16,17); interference with daily life (^3,4); emotional impact (^{2,12,13,15,22}); and disease outcome concerns (^18,19, 23, 25). Many of the items in other domains also reflect emotional impact. A comparison of the numbers of items in each domain from the phase II instrument and the phase III instrument is given in Table 1. The instrument was assessed for Flesch-Kincaid readability at a grade I level compared with a short story by Hemingway (grade 4 level) or this paper (grade 15.7 level). The phase III instrument is provided in the Appendix.

TABLE 1: Comparison of the number of items per domain in the Phase II parental burden questionnaire and the Phase III questionnaire

Child Burden Instrument

For the children with ITP, few questions resulted in an MRS score greater than 2 (for the child response questionnaire, two items; for the proxy response questionnaire, six items). Therefore, to determine items with the greatest level of burden, the questionnaire was screened for elements with a mean response score of 1.3 or greater (from the scaling: not at all [0], hardly at all [1], some [2], a lot [3], very, very much/often [4]). The score of 1.3 was chosen to reflect the items of greatest burden as identified by the children involved (or their proxy), as the number of items with a score of 1.2 or less increased markedly. A seven-point Likert scale is used for the phase III questionnaire, thus potentially increasing the sensitivity and responsiveness of the questions. There were no apparent “floor” or “ceiling” effects noted. For multipart questions, the stem question as well as the other components of a multipart question were screened to assess total burden related to that item.

This process yielded a total of 18 stem questions from the self-assessment questionnaire and 23 stem questions from the proxy questionnaire, giving 29 questions (from the 41 questions, as 12 were identified with an MRS of at least 1.3 by both self-assessment and proxy assessment). These questions were supplemented by additional questions identified through subgroup analysis. Examination of responses for children with platelet counts less than 20 × 10⁹/L identified eight more items (three considered important by both child and proxy); for acute/chronic, one additional item was considered important by proxy response; for age younger than 7 years, three new items were flagged through proxy responses.

These questions were then examined for degree of correlation with other questions using Pearson's correlation coefficient, SAS version 8.0. Two sets of highly correlated questions (P < 0.0001, correlation coefficient >0.5) addressing similar areas were noted, and one of each set was eliminated for the phase III questionnaire. Correlations between child and proxy responses were calculated. Items were deleted if they were not identified by the child self-assessment questionnaires as important and highly correlated with the proxy responses. Exceptions were made when the difference between child and proxy responses appeared to reflect concerns for a young child or where a proxy assessment would be expected to be more accurate. For example, children older than 7 were not bothered by having to take oral medicine, whereas young children were perceived by their parents to be upset. In general, parents rated the burden to their child as higher than the child did himself or herself. However, items not resulting in easily interpretable or observable behaviors or not communicated to the parent, such as worrying about his or her platelet count, were rated lower in the proxy responses.

The responses to the phase II questionnaire were then completely reviewed. The final items appeared to have face validity and content validity. The final chosen items were then re-examined for clarity and to ensure they reflected burden to the child with ITP and had the potential to reflect changes in the course of the child's ITP. The final phase III questionnaire has 26 questions.

The domains reflected in the phase III questionnaire were determined by reviewing the questions for logical groupings and by degree of correlation, identical to the processes used for the parent burden questionnaire. This combination of approaches was used to group the questions into five domains: treatment side effect-related (^{2,3,4,5,7,19,20}, 24); intervention-related (^8,9,10,11, 25); disease-related (^{6,15,16,17,18,21}, 23, 26); activity-related (^1,12,13); and family-related (^14,22). Table 2 gives a comparison of the number of items in each domain for the phase II and the phase III questionnaire.

TABLE 2: Items per domain in the Phase II child burden questionnaire and after item reduction for the Phase III questionnaire

The questionnaire was assessed for readability using the Fleisch-Kincaid reading ease criteria. The questionnaire is at a grade 0.5 level, compared with a short story by Hemingway at a grade level of 4. The final phase III questionnaire is provided in the Appendix. The phase III questionnaire can be used as a self-completed instrument for children older than 7 years and as a proxy instrument for children younger than 7 years.

DISCUSSION

The approach to the care of children with ITP remains a topic of intense debate among pediatricians and pediatric hematologists (^1,4). Some stress the benign, self-limited nature of the disorder (^5,6) whereas others, concerned with the small but real risk of intracranial bleeding, have recommended treatment of all children with a platelet count less than 20 × 10⁹/L (³) or children with a platelet count less than 20 × 10⁹/L and mucocutaneous, “wet” purpura. Indications for bone marrow aspiration and for hospitalization are also disputed (^6–8).

This controversy over appropriate therapy for ITP emphasizes the need for new evaluative tools to complement traditional clinical measures. Traditional clinical measures such as platelet counts provide important information on both outcome and prognosis but reveal little about how the child (or parent) feels (¹⁵). However, the issues facing children with ITP and their parents are not sufficiently captured by available generic quality-of-life instruments or measures.

Under circumstances of relative equipoise of treatment options, impact on patients, their families, and their self-defined quality of life becomes important. As reported by participants in this study, parents of children with ITP experienced stress or felt a burden both from the impact on their own lives and that of their family, but also from the vicarious stress derived from the burden they perceived that their child endured. In general, parents expressed a higher level of burden than their child reported. The phase III ITP-Child Quality-of-Life Questionnaire and ITP-Parental Burden Quality-of-Life Questionnaire will help quantify these burdens. The ITP-Parental Burden Quality-of-Life Questionnaire is one of few instruments specifically designed to measure the burden experienced by parents due to their child's illness.

The development of health-related quality-of-life instruments requires a rigorous process to ensure that the final instrument provides useful information, is valid (measures what it claims to measure), and is responsive to small but clinically important changes and differences. Health professionals may understand and identify some of the stresses of children. However, when information is sought directly from patients and parents, concerns that are not intuitively obvious are ascertained. For example, the process used for the development of this instrument identified that children felt more tired than usual. The formulation of an instrument that meets the criteria of a useful measure (a measure that has validity, reliability, responsiveness, interpretability, applicability, and acceptability)(¹⁶) must follow an established method (¹⁷), such as was followed to develop the present questionnaires.

When developing this instrument, as for other instruments dealing with the health-related quality of life of young children, we faced the dilemma of validity of proxy versus self-assessment. As the average age (mean and median) of children with acute ITP in this study was approximately 4 years, the concerns of these children were mainly represented by information obtained from their parents. For young schoolchildren and preschoolers, the proxy input of parents was accepted as the most accurate information available. Many studies have examined the correlations between assessment of health status and quality of life by children and by their parents. For school-age children, in general, the highest agreement between child and parent assessments is for symptoms that are concrete, observable, severe, and unambiguous. Parents tend to report more behavioral symptoms and children more subjective symptoms and somatic complaints (¹⁸). These behavioral symptoms may be those troublesome or more obvious to the parent.

For parents, areas of greatest concern including wanting to understand more about ITP (MRS 2.5), feeling the need to check the child frequently (MRS 2.9) and to protect the child from injury (MRS 2.1), worrying about complications of the ITP (MRS 2.5), and concern about potential complications of the treatment (MRS 2.1). Concern about potential complications of splenectomy is expected to be captured by the questions related to complications of treatment (questions 2 and 10). For the 22 parents whose child had a bone marrow test, the MRS for the stress felt by the parent was 3.5. The concerns identified are in keeping with those more informally expressed on websites related to childhood ITP. For children with ITP, areas of concern included worrying about their platelet count (MRS 1.4) and receiving treatment through an intravenous infusion (MRS 1.5). For the parents of children who had a bone marrow test, the burden they felt was reflected in an MRS of 3.5; for the child older than 7 years, the MRS was only 1.3, perhaps related to the use of deep sedation for the procedure.

For older children, minimizing symptoms or physical disorders may be a way of coping or the result of recalibrating expectations and acceptance of disabilities/disorders (^19,20). Guyatt et al. (²¹) found that the assessments by children with asthma aged 11 years or older with respect to asthma control and health-related quality of life were more similar to the proxy assessment by their parent than the assessments by younger children compared with that of their parents. It was speculated that older children are more articulate in expressing feelings and concerns. For the purpose of developing the questionnaire, we chose to place greater emphasis on the child's assessment than that of the parents. For almost all items, the difference between proxy and child response was in the relative degree of burden; both children and proxy identified the same items of greatest concern.

In this study, parents did not find the costs related to parking, travel, long-distance calls, or missed time from work burdensome. Conceptually, cost items belong in an economic burden instrument and therefore were not included in our health-related quality-of-life instrument. These areas may assume more importance in other health care settings and should be included in instruments used to assess the economic burden of ITP.

Rather than developing several instruments (for example, one for children or parents of children with acute ITP and one for children or parents of children with chronic ITP), we elected to develop an instrument that reflected the concerns of children with ITP and their parents, irrespective of the child's age or the chronicity of disease. Most questions retained in the phase III instruments were considered important by children with acute ITP and by children with chronic ITP as well as by differing age groups, except as noted above. The resulting instruments do contain a few items that are not applicable to subgroups of children with ITP or their families (for example, “Did getting your treatment through an IV bother you?”). These questions have a nonapplicable response option. These few items were not felt to attenuate the potential validity and usefulness of the instrument. Some items that we as health care professionals might think would be less bothersome for one group versus another were of significant concern for both groups. For example, for the question “Did you worry that your child had a serious disease such as leukemia?” the MRS of the parents of a child with acute ITP was 2.7 ± 1.8, whereas that of a child with chronic ITP was 2.1 ± 1.9. However, the concern was greater for parents of children younger than 8 years than for older children (2.8 vs. 1.5). Larger numbers of children/parents in each category will need to be tested to confirm these findings. A single instrument for children and a single instrument for parental burden have the advantages of simplicity and ease of use for long-term follow-up studies.

As has been done for other instruments (²²), our plans for the ongoing development of these instruments include the assessment of the reliability, validity, and responsiveness of the instruments within the context of clinical research trials. Test–retest reliability, discriminative validity (ability of the instruments to accurately discriminate among differing populations), longitudinal construct validity (ability of the instrument to accurately reflect change over time), and responsiveness/sensitivity to change will be assessed in the clinical research setting. This will be an ongoing process, each clinical research study strengthening the evidence on the usefulness of the instruments. Controlled clinical trials offer the opportunity to evaluate the validity of an instrument, such as the ones reported here, through analysis of the results from comparable populations undergoing different interventions that would be expected to induce improvement in platelet counts and clinical symptoms. The clinical trial setting will offer the opportunity to induce changes in a patient population comparable at the onset and the collection of prospective data to evaluate the induced changes.

Acknowledgments:

This study could not have been completed without the collaboration of members of the Canadian Children's Platelet Study Group, colleagues in the United States, and the Clinical Research Associates at each participating institution. Members of the Canadian Children's Platelet Group are as follows (asterisks indicate those who contributed patients to the study): Sharon Abish, M.D., Montreal Children's Hospital; John Akabutu, M.D., University of Alberta Hospital; Kaiser Ali, M.D., University of Saskatchewan; Ron Anderson, M.D., Alberta Children's Hospital; Dorothy Barnard, M.D.,* Dalhousie University; Victor Blanchette, M.B.,* University of Toronto, Toronto Hospital for Sick Children; Manuel Carcao, M.D.,* Toronto Hospital for Sick Children; Michele David, M.D.,* University of Montreal; Jeanne Drouin, M.D., Ottawa General Hospital; Sara Israels, M.D., University of Manitoba; Lawrence Jardine, M.D., Children's Hospital of Western Ontario; Brian Luke, M.D., Children's Hospital of Eastern Ontario; Pat McCusker, M.D.,* University of Manitoba; Mohan Pai, M.D., McMaster University; Margaret Rand, Ph.D., University of Toronto; Toronto Hospital for Sick Children; Mary-France Scully, M.D., Health Sciences Center, Newfoundland; Mariana Silva, M.D.,* Queen's University; John Wu, M.D.,* University of British Columbia. Centers in the United States: James Bussel, M.D.,* Cornell University; Jean Lusher, M.D.,* Wayne State University. Clinical research coordinators associated with study: Halifax: Shaureen Taweel, B.N.; Montreal: Irene Poirier, R.N.; Toronto: Susan Henriques, B.A., Cindy Wakefield, R.N., B.A.; Kingston: Julie Parker, M.S.W., Jeff Stewart; London: Julie Nichols; Winnipeg: Linda Archer; Vancouver: Traci Corr, R.N., B.Sc., B.S.N.; New York: Mathew Schonholz; Detroit: Danna Merritt, M.S.W.