Chart 1. Most important parameters in regression analyses and their interpretations.
| Parameter | Linear regression | Logistic regression |
|---|---|---|
| Direction and strength of the association between the independent variable and the dependent variable (outcome) | Beta coefficient: Describes the (expected) average change in the outcome variable for each one-unit change in the independent variable for continuous variables, or the average change in the outcome variable for one category of the independent variable compared with a reference category for categorical variables |
OR: The OR for a continuous independent variable is interpreted as the change in the odds of the outcome occurring for every one-unit increase in the independent variable The OR for categorical independent variables is interpreted as the increase or decrease in odds between two categories (e.g., men vs women) OR = 1: no association; OR > 1: positive association or risk factor; and OR < 1: negative association or protective factor |
| Example (for a continuous independent variable) | The expected increase in FEV1 for each centimeter increase in height | The expected increase in the odds of death for each increase of one year of age among patients with sepsis |
| Example (for a categorical independent variable) | The expected increase in FEV1 for men compared with women with the same height and age | The expected increase in the odds of death for men compared with women among COVID-19 patients |
| Precision of the estimate | The 95% CI of the beta coefficient | The 95%CI of the OR |
| Statistical significance | The p value (significant when < 0.05) | The p value (significant when < 0.05) |