Using a backwards logistic regression model, plasma DNA was the only independent factor that could predict ICU mortality (odds ratio, 1.002 (95% confidence interval, 1.0 1.004), P = 0.05).
These psychological variables are closely correlated and, when entered with urgency into a backwards logistic regression model using the 72 cases with data for all variables, only depression remained an independent predictor in the model (p=0.012).
Backwards logistic regression models were used to determine the effect of the duration of mechanical ventilation on the presence of dysphagia, and the effect of dysphagia on patient outcomes.
To determine independent predictors for unplanned ED readmission at 1 month and 3 months in patients discharged home, all variables with P ≤ .20 in the univariate analyses were included in a multivariate backwards logistic regression model.
Clinical variables were also analysed for association with functional MAVS SNP genotypes in the African-American SLE patients using logistic regression, and in this case carriage of the C79F and Q198K minor alleles was the outcome variable in a backwards logistic regression model which included each of the 11 ACR clinical criteria for the diagnosis of SLE as predictor variables (Tan et al, 1982).
This process used R scripts calling SQL server stored procedures to extract and simulate clusters, followed by backwards conditional logistic regression modelling with the stepAIC function from the R MASS package[ 15].
Logistic regression modelling.
Backwards step-wise logistic regression modelling was undertaken, including those variables where bivariate relationships were observed, to identify those independently associated with dementia beliefs and knowledge.
