Note¶
This analysis includes a quadratic term for PMA at first oral feeding (i.e., both the variable and its square are included in the model).
Secondary Analysis: pma_at_first_oral_feeding vs pma_at_full_oral_feeding¶
Analysis of pma_at_first_oral_feeding vs pma_at_full_oral_feeding.
Unadjusted Model Results¶
Simple quadratic regression examining the direct relationship between pma_at_first_oral_feeding and pma_at_full_oral_feeding.
Model diagnostics warning: High multicollinearity detected (condition number > 30). Residuals may not be normally distributed (p < 0.05). Heteroscedasticity detected (p < 0.05).
Outcome: pma_at_full_oral_feeding Predictor: pma_at_first_oral_feeding and its square
OLS Regression Results
====================================================================================
Dep. Variable: pma_at_full_oral_feeding R-squared: 0.399
Model: OLS Adj. R-squared: 0.394
Method: Least Squares F-statistic: 74.71
Date: Tue, 05 Aug 2025 Prob (F-statistic): 1.31e-25
Time: 04:28:18 Log-Likelihood: -464.36
No. Observations: 228 AIC: 934.7
Df Residuals: 225 BIC: 945.0
Df Model: 2
Covariance Type: nonrobust
================================================================================================
coef std err t P>|t| [0.025 0.975]
------------------------------------------------------------------------------------------------
const 93.7388 42.070 2.228 0.027 10.838 176.640
pma_at_first_oral_feeding -4.2152 2.391 -1.763 0.079 -8.927 0.497
pma_at_first_oral_feeding_sq 0.0742 0.034 2.186 0.030 0.007 0.141
==============================================================================
Omnibus: 54.314 Durbin-Watson: 1.476
Prob(Omnibus): 0.000 Jarque-Bera (JB): 93.807
Skew: 1.264 Prob(JB): 4.27e-21
Kurtosis: 4.866 Cond. No. 4.05e+05
==============================================================================
Notes:
[1] Standard Errors assume that the covariance matrix of the errors is correctly specified.
[2] The condition number is large, 4.05e+05. This might indicate that there are
strong multicollinearity or other numerical problems.
Unadjusted Plot¶
Plot showing relationship between pma_at_first_oral_feeding and pma_at_full_oral_feeding (LOESS with CI and Quadratic prediction).
Model Variables (Adjusted Analysis)¶
Outcome: pma_at_full_oral_feeding Indep: pma_at_first_oral_feeding Gestational Age Var: gestational_age_weeks Confounders: ['gestational_age_weeks', 'birth_weight_grams', 'mechanical_ventilation', 'o2_device_at_36_weeks'] Covariates: ['medicalcomplexity']
Adjusted Model Results¶
Multiple regression examining the relationship between pma_at_first_oral_feeding and pma_at_full_oral_feeding, controlling for gestational age and other potential confounders.
Model diagnostics warning: High multicollinearity detected (condition number > 30). Residuals may not be normally distributed (p < 0.05). Heteroscedasticity detected (p < 0.05).
Outcome: pma_at_full_oral_feeding Predictors: pma_at_first_oral_feeding, gestational_age_weeks, pma_at_first_oral_feeding_sq, birth_weight_grams, mechanical_ventilation_no history of mechanical ventilation, o2_device_at_36_weeks_did NOT require respiratory support at 36 weeks, medicalcomplexity_Children with noncomplex chronic disease, medicalcomplexity_Children without chronic disease
OLS Regression Results
====================================================================================
Dep. Variable: pma_at_full_oral_feeding R-squared: 0.483
Model: OLS Adj. R-squared: 0.464
Method: Least Squares F-statistic: 25.53
Date: Tue, 05 Aug 2025 Prob (F-statistic): 1.23e-27
Time: 04:28:20 Log-Likelihood: -447.30
No. Observations: 228 AIC: 912.6
Df Residuals: 219 BIC: 943.5
Df Model: 8
Covariance Type: nonrobust
=========================================================================================================================================
coef std err t P>|t| [0.025 0.975]
-----------------------------------------------------------------------------------------------------------------------------------------
const 104.3741 40.462 2.580 0.011 24.629 184.120
pma_at_first_oral_feeding -4.4657 2.327 -1.919 0.056 -9.052 0.120
gestational_age_weeks -0.0317 0.117 -0.270 0.788 -0.263 0.200
pma_at_first_oral_feeding_sq 0.0748 0.033 2.270 0.024 0.010 0.140
birth_weight_grams -0.0007 0.001 -1.154 0.250 -0.002 0.000
mechanical_ventilation_no history of mechanical ventilation -0.7881 0.290 -2.717 0.007 -1.360 -0.216
o2_device_at_36_weeks_did NOT require respiratory support at 36 weeks -0.3807 0.307 -1.242 0.216 -0.985 0.224
medicalcomplexity_Children with noncomplex chronic disease -0.1428 0.704 -0.203 0.839 -1.531 1.245
medicalcomplexity_Children without chronic disease -0.3674 0.555 -0.663 0.508 -1.460 0.725
==============================================================================
Omnibus: 79.650 Durbin-Watson: 1.654
Prob(Omnibus): 0.000 Jarque-Bera (JB): 223.563
Skew: 1.534 Prob(JB): 2.84e-49
Kurtosis: 6.757 Cond. No. 6.02e+05
==============================================================================
Notes:
[1] Standard Errors assume that the covariance matrix of the errors is correctly specified.
[2] The condition number is large, 6.02e+05. This might indicate that there are
strong multicollinearity or other numerical problems.
Adjusted Plot¶
Plot showing adjusted relationship between pma_at_first_oral_feeding and pma_at_full_oral_feeding (LOESS with CI).
Relationship Analysis¶
Adjusted plot shows relationship.