Table III.
Logistic-Normal Generalized Linear Mixed-Model Estimates of the Probability of Being in NYHA/Ross Class III or IV for a Hypothetical Average Child with Dilated Cardiomyopathy
| Predictor | Patients, n Observations, n | Predictor Sample Mean | P (NYHA/Ross III or IV) (95% CI)* | Odds Ratio for NYHA/Ross Class III or IV vs. Class I or II (95% CI)† | P† |
|---|---|---|---|---|---|
| log10(NT-proBNP)‡ | 34 (198) | 2.83 | 0.14 (0.03, 0.44) | 85.48 (10.89, 671.02) | <0.001 |
| LVEF (%) | 34 (121) | 44.8 | 0.08 (0.02, 0.26) | 0.83 (0.77, 0.89) | <0.001 |
| LVSF-z | 36 (128) | −5.33 | 0.09 (0.02, 0.35) | 0.58 (0.59, 0.79) | <0.001 |
| LVDD-z | 36 (131) | 3.03 | 0.06 (0.01, 0.39) | 1.75 (1.39, 2.21) | <0.001 |
| LVSD-z | 36 (128) | 4.46 | 0.03 (0.00, 0.44) | 1.67 (1.39, 2.02) | <0.001 |
The bivariate association between the probability of being in NYHA/Ross class III or IV and each predictor was examined using a logistic-normal generalized linear mixed model with a random intercept and the predictor as a single covariate. The probability of being in class III or IV and its 95% CI for a hypothetical average child was estimated at a predictor value equal to the sample mean of the predictor and at a random intercept of zero.
The within-patient change in the odds of being in NYHA/Ross class III or IV for a 1-unit change in the predictor, expressed as an odds ratio, and its 95% CI were estimated using the same logistic-normal generalized linear mixed model. A 1-unit change in log10 (NT-proBNP) corresponds to a 10-fold increase in NT-proBNP measured in pg/mL (e.g., from 104 pg/mL to 1040 pg/mL). The P value is for the test of the null hypothesis of no within-patient change in odds (or an odds ratio of 1).
The sample arithmetic mean of approximately 2.82 log10 units corresponds to a sample geometric mean of 660 pg/mL
LVEF, left ventricular ejection fraction; LVSF-z, left ventricular shortening fraction relative to age z-score; LVDD-z, left ventricular diastolic diameter relative to body surface area z-score; LVSD-z, left ventricular systolic diameter relative to body surface area z-score; NYHA, New York Heart Association; NT-proBNP, N-terminal pro-hormone brain natriuretic peptide.