followupduur

Followupduur is a Dutch term used to describe the length of the follow-up period after an intervention, during which participants are observed for outcomes. The word combines follow-up with duur, meaning duration. In practice, followupduur denotes how long data on effects, safety, or secondary outcomes are collected after the initial treatment or exposure.

Applications are common in clinical research and health care management. In clinical trials, the follow-up duration is specified in the protocol and influences the timing of endpoint assessment, safety monitoring, and statistical analysis. In routine care, it refers to ongoing surveillance after a procedure or therapy to detect recurrence, late adverse events, or long-term efficacy.

Measurement and considerations: The follow-up duration is typically expressed in months or years. Analyses may treat time to event or repeated observations, with censoring when participants drop out or are lost. Longer follow-up can reveal late effects but increases cost and the risk of attrition, potentially biasing results if losses are differential.

Examples: A cancer trial with a 5-year follow-up to assess disease-free survival; a vaccine study with a 12-month follow-up for adverse events; a cohort study of chronic disease where follow-up extends over decades.

Limitations: Varied definitions across studies can hinder comparability; inconsistent reporting of follow-up length complicates meta-analyses; missing data from dropouts pose analytical challenges.

See also: follow-up, duration, clinical trial endpoint, survival analysis.