Calculadora de Risco Relativo

The Relative Risk (RR) Calculator is a statistical tool that measures the association between an exposure and an outcome in epidemiological studies. It uses a classic 2×2 table with four groups: exposed with outcome (a), exposed without outcome (b), unexposed with outcome (c), and unexposed without outcome (d). The RR is calculated by dividing the incidence in the exposed group (a/(a+b)) by the incidence in the unexposed group (c/(c+d)). An RR of 1 indicates no association; greater than 1 suggests increased risk; less than 1 suggests protection.

When to use? In cohort studies, randomized clinical trials, or systematic reviews when comparing the probability of an event between two groups. For example, in a study evaluating whether smokers have a higher risk of lung cancer, RR compares the cancer rate between smokers and non-smokers. The calculator is useful for researchers, healthcare professionals, and students needing quick results without manual errors.

Important precautions: RR is only valid if the 2×2 table data is correctly classified. Ensure exposure and outcome are binary and the sample is representative. Extreme RR values (very high or low) may occur with small samples; confidence intervals are essential in such cases. The calculator does not replace adjusted analyses for confounders, such as logistic regression.

Interpretation of RR depends on clinical context. An RR of 2.0 means the exposed group has twice the risk of developing the outcome compared to the unexposed. However, RR does not inform about absolute risk (risk difference) or population impact (attributable fraction). Use alongside other measures like odds ratio and attributable risk for a complete analysis.