JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD Pharm. D V Year PHARMACOEPIDEMIOLOGY AND PHARMACOECONOMICS Previous Question Paper (October/November - 2019 - R08)

Risk measurement is the cornerstone of pharmacoepidemiology, allowing researchers to quantify the association between drug exposure and health outcomes. These measurements are primarily derived from cohort and case-control study designs.

The fundamental measures of risk include:

• Incidence Proportion (Risk): This is the probability that an event will occur within a specified period. It is calculated as the number of new cases of a disease divided by the total population at risk at the beginning of the period.
• Incidence Rate (Incidence Density): This measures the speed at which new cases occur in a population. It is calculated as the number of new cases divided by the total person-time at risk.
• Relative Risk (Risk Ratio): Used in cohort studies, this compares the risk of an outcome in the exposed group to the risk in the unexposed group. A value of 1 indicates no association, while values greater than 1 suggest an increased risk.
• Odds Ratio (OR): Typically used in case-control studies, it represents the odds of exposure among cases compared to the odds of exposure among controls. It serves as an estimate of the relative risk when the disease is rare.
• Attributable Risk (Risk Difference): This measures the absolute difference in risk between the exposed and unexposed groups, indicating the excess risk that can be attributed to the drug exposure.
• Number Needed to Harm (NNH): This is the inverse of the attributable risk (1 / Risk Difference) and represents the number of patients who need to be treated with a specific drug for one additional patient to experience an adverse event.

These measures are essential for evaluating the safety profile of medications, identifying potential drug-induced side effects, and supporting regulatory decisions regarding drug labeling and post-marketing surveillance.