What is the definition of person-years (PY)?

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From the Guidelines

Person-years is a measurement unit used in epidemiology and medical research to quantify the amount of time individuals are observed in a study while being at risk for a particular outcome, calculated as the sum of the time periods that each participant contributes to a study. This concept is crucial in understanding the incidence rates of diseases or events, as seen in the analysis of malignancy rates in patients receiving pimecrolimus 1. The person-years of exposure, such as 278,842 person-years in one age group, allows researchers to calculate the expected number of cases and compare it to the reported cases, providing valuable insights into the risk of certain outcomes.

Key Points

  • Person-years represents the total time individuals are at risk for a particular outcome
  • It is calculated by summing the time periods each participant contributes to a study
  • This measurement is essential for calculating incidence rates and standardizing risk across different study designs
  • Person-years enables researchers to account for varying follow-up times and dropout rates, making it a more accurate representation of risk than simple percentages. For instance, in the context of the provided study 1, person-years of exposure is used to analyze the malignancy rates in patients receiving pimecrolimus, demonstrating the importance of this measurement unit in epidemiological research.

From the Research

Definition of Person-Years (PY)

There are no research papers provided that directly define person-years (PY).

Related Concepts

However, some studies mention related concepts such as:

  • Person-centered care, which is emphasized in the Nursing and Midwifery Council's 2018 Future Nurse proficiency standards 2
  • Person-context co-construction, which is considered to contribute to the emergence, maintenance, and disengagement from healthy aging relevant goals in adulthood and old age 3
  • Person-centered interventions, which have been utilized to enhance health-related outcomes and ensure the quality of care delivered to persons living with dementia 4

Lack of Direct Evidence

Since none of the provided studies directly address the definition of person-years (PY), it is not possible to provide a clear definition based on the available evidence 5, 6, 2, 4, 3

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Assessing the patient's needs and planning effective care.

British journal of nursing (Mark Allen Publishing), 2021

Research

Healthy Aging-Relevant Goals: The Role of Person-Context Co-construction.

The journals of gerontology. Series B, Psychological sciences and social sciences, 2021

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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