overlevelsesfrekvensen

Overlevelsesfrekvensen is a statistical concept commonly used in epidemiology and medical research to describe the probability or proportion of individuals who remain alive after a defined starting point, such as diagnosis, treatment initiation, or exposure. It is a key measure for assessing outcomes in populations and can be reported for specific time horizons (for example, 1-year or 5-year survival) or depicted as a survival curve over time.

Two main forms are often distinguished in practice. Overall survival (OS) represents the proportion of individuals alive regardless of cause of death. Disease-specific survival (DSS) or cancer-specific survival refers to the proportion alive without death from the disease of interest. In oncology, related measures include progression-free survival (PFS) and disease-free survival (DFS), which focus on time until disease progression or recurrence, rather than overall mortality.

Estimating the overlevelsesfrekvensen typically employs survival analysis methods. The Kaplan-Meier estimator, or product-limit method, derives the survival function from time-to-event data, accounting for censoring. Life-table methods provide alternative estimates over fixed intervals. Regression approaches, such as Cox proportional hazards models, assess how covariates affect survival risk.

Data sources include population-based cancer or health registries, hospital records, and national health databases. Interpretation should consider factors like stage at diagnosis, treatment advances, and patient characteristics. Potential biases include lead-time and length-time biases, censoring issues, and competing risks, which can influence comparisons across studies or over time.

The term is widely used across medical and public health research, and its precise meaning may vary with the context and the defined starting point and time horizon.