Health outcomes
Physical health outcomes. Clinically-assessed health conditions
were evaluated during on-campus medical evaluations and defined using
modified Common Terminology Criteria for Adverse Events (CTCAE) version
4.03 criteria adapted for childhood cancer
survivors.21 Comprehensive medical assessments
included diagnostic procedures, an assessment of neuromuscular function,
and a physical evaluation with a standardized laboratory battery. At the
time of assessment, if survivors reported any chronic health conditions
previously diagnosed, medical records were obtained to validate these
diagnoses. The following organ systems were evaluated during the medical
assessment and included as outcome variables: cardiac, pulmonary, renal,
endocrine, gastrointestinal/hepatic, neurologic and musculoskeletal.
CTCAE grades range from 1-4 (mild [grade 1], moderate [grade 2],
severe or disabling [grade 3], life-threatening [grade 4]), and
adverse health conditions were defined as grade ≥2 for each condition
(i.e. moderate to life threatening). Supplemental Tables S2a-g present
the frequency of grade 2-4 conditions for study participants, classified
by each organ system. Chronic health conditions were included if they
were diagnosed prior to and up to three months following the sleep
assessment.
In addition to evaluating health conditions by each organ system, we
created a composite measure assessing the burden/severity of the
survivor’s physical health. A method developed by Geenen et
al.22 was employed to aggregate chronic health
conditions across organ systems (cardiovascular, pulmonary, endocrine,
neurologic, gastrointestinal, musculoskeletal, and renal), taking into
account the frequency and grade of conditions. For survivors who had
multiple chronic health conditions within the same organ system, the
highest grade within that organ system was utilized. This chronic health
burden score was classified via the following categories: none, low
(only grade 1 events), medium (having ≥1 grade 2 event and/or 1 grade 3
event), high (having ≥ 2 grade 3 events or 1 grade 4 event and at most 1
grade 3 event), and severe (>1 grade 4 events or ≥ 2 grade
3 events and 1 grade 4 event).
Psychological health outcomes. The Brief Symptom Inventory-18
(BSI-18)23 was administered at the time of the
participant’s sleep evaluation to assess clinically significant anxiety
and depression. Using sex-specific normative data, survivors with a
T-score ≥63 (90th percentile) on either subscale were
classified with clinically significant anxiety and/or depression. The
BSI-18 has been previously validated in childhood cancer
survivors.24