Cohort construction
Children less than 18 years-old were enrolled, and the day of the blood
draw for cholesterol measurements was defined as the index date.
Subjects with atopic dermatitis diagnosis codes or prescriptions for
treatment of atopic dermatitis before the index date were excluded.
Children were also excluded if they had previous recorded diagnoses of
contact dermatitis, psoriasis, scabies, ichthyosis, erythroderma,
photodermatitis, or seborrheic dermatitis. Subjects were separated into
a high TC group and a low TC group according to a blood TC level of 170
mg/dL.21 The propensity model and outcome definitions
all operate on data that are converted into the CDM.19Thus, there were matching for age, sex, medications, procedures, and
measurements based on the medical records of patients in the high and
normal TC groups. The association of TC with the onset of atopic
dermatitis was assessed using medical data from Kandong Sacred Heart
Hospital. The unmatched cohort had 3,913 children with TC levels of 170
mg/dL or more (high TC group) and 48,812 children with TC levels below
170 mg/dL (normal TC group). After 1:4 propensity score matching, the
matched cohort had 1,722 subjects in the high TC group and 6,735
subjects in the normal TC group.