1årsoverlevelsen

1årsoverlevelsen, or one-year survival, is a statistic used in medicine to measure the proportion of people who are alive one year after a defined starting point, such as diagnosis or initiation of treatment. It is commonly used to assess prognosis and the short-term effectiveness of therapies, particularly in cancer and cardiovascular diseases.

Typically, estimates are derived from survival analysis, using methods such as the Kaplan-Meier estimator or actuarial life-table approaches. The starting point (time zero) and the definition of the endpoint (one year) are fixed, and individuals who are lost to follow-up are censored. Results can be reported as a crude proportion or as a relative one-year survival, which compares observed survival to that expected in a comparable general population.

1årsoverlevelsen varies with disease type, stage, patient age, comorbidity, and treatment. It is often reported for specific subgroups and can be presented as 'one-year survival by stage' in cancer registries. The concept of conditional survival, such as the probability of surviving the next year given survival to a certain point, is also used in prognosis.

Limitations include censoring, lead-time bias from screening, differences in follow-up duration, and population differences that affect comparability. The measure does not capture longer-term outcomes nor quality of life. Therefore 1årsoverlevelsen is most informative when interpreted alongside other metrics such as five-year survival, disease-specific survival, and functional outcomes.

Data sources for 1årsoverlevelsen include national cancer registries, hospital records, and clinical trials. Reporting standards vary by country and disease area, affecting cross-country comparisons. In research and clinical practice, the statistic provides a concise, early indicator of prognosis and treatment impact.