Name: life table method for survival rates
Uploaded: 2025-01-09T15:14:16.000Z
Duration: 1 min 20 s
Channel: JoVE

El análisis de supervivencia evalúa el tiempo que transcurre hasta que ocurre un evento, como la muerte o el fracaso del tratamiento. El enfoque actuarial o de tabla de vida, adaptado de la ciencia actuarial, analiza los datos de supervivencia.
En un escenario de estudio clínico, los participantes se dividen en grupos con diferentes duraciones de seguimiento para centrarse en los períodos críticos, como el primer año después de la cirugía de alto riesgo.
El método actuarial calcula las tasas de supervivencia a intervalos predeterminados, utilizando plenamente los datos de todos los participantes, incluidos los que se perdieron durante el seguimiento o los que han fallecido por otras causas.
Para comprender el impacto en la supervivencia del primer año, las tasas de supervivencia a un año se derivan restando el número de muertes del total de participantes y dividiéndolo por el número original.
Solo se considera el subconjunto de pacientes observados durante los dos años completos para estimar la supervivencia a dos años, centrándose en aquellos que sobrevivieron el primer año y luego continuaron sobreviviendo el segundo año.
Este método es consistente, ayuda a identificar tendencias a largo plazo y evalúa la efectividad de los tratamientos o intervenciones, proporcionando una herramienta sólida para comprender los resultados en la investigación médica.

enfoque actuarial

Actuarial Approach

El enfoque actuarial, un método estadístico desarrollado originalmente para la evaluación de riesgos de seguros de vida, se utiliza ampliamente para calcular las tasas de supervivencia en estudios clínicos y de población. Este método tiene en cuenta a los participantes que se pierden durante el seguimiento o que mueren por causas no relacionadas con el estudio, lo que garantiza una representación más precisa de las probabilidades de supervivencia.

Consideremos el ejemplo de un procedimiento quirúrgico de alto riesgo con una mortalidad significativa en la etapa temprana. Se lleva a cabo un estudio clínico de dos años, centrándose en el primer año crítico. Los participantes se dividen en dos grupos: uno es seguido durante un año y otro durante dos años. Las tasas de supervivencia se calculan utilizando el método actuarial (o de tabla de mortalidad), que divide el período de estudio en intervalos, normalmente un año.

Para ilustrarlo, supongamos que el primer grupo comienza con 1000 pacientes, de los cuales 240 mueren durante el primer año. El segundo grupo también comienza con 1000 pacientes, con 200 muertes en el primer año y 16 en el segundo año. La tasa de supervivencia a un año se calcula restando el número total de muertes del tamaño de la cohorte inicial y dividiendo el resultado por la población inicial:

Tasa de supervivencia a un año = (2000−240−200)/2000=0,78 o 78 %

Este enfoque también se puede aplicar a estudios de resultados a largo plazo, como la evaluación de la eficacia de un tratamiento contra el cáncer a lo largo de los años. El método actuarial tiene en cuenta a los pacientes que se pierden durante el seguimiento o que mueren por causas no relacionadas, lo que permite un análisis sólido de los efectos a largo plazo.

Para las tasas de supervivencia a dos años, el cálculo se vuelve más matizado. Utiliza la probabilidad condicional, considerando solo a los individuos observados durante los dos años completos y que sobrevivieron el primer año. La tasa de supervivencia a dos años no debe superar la tasa a un año y se determina multiplicando la probabilidad de supervivencia al primer año por la probabilidad de supervivencia al segundo año, siempre que se sobreviva al primer año:

Tasa de supervivencia a dos años = 0,78 × 0,98 = 0,7644 o 76,44 %

Este sofisticado método, aunque potente, se enfrenta a desafíos como los datos de seguimiento incompletos y el registro preciso de las muertes. A pesar de estas limitaciones, sigue siendo particularmente eficaz en estudios de población a gran escala en los que el seguimiento de los participantes individuales es poco práctico. Al tener en cuenta la censura y las probabilidades de supervivencia basadas en intervalos, el enfoque actuarial proporciona un marco fiable para el análisis de la supervivencia en diversos contextos de investigación.

Enfoque actuarial

El análisis de supervivencia evalúa el tiempo que transcurre hasta que ocurre un evento, como la muerte o el fracaso del tratamiento. El enfoque actuarial o de la tabla de vida, adaptado de la ...

Education

Educación

JoVE Core

Statistics

Estadísticas

Unit 1

Unidad 1

Survival Analysis

Análisis de supervivencia

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

life table method for survival rates

The life table method, also called the actuarial approach, is used to estimate survival rates in clinical and population studies. It began in life insurance, where risk over time must be measured carefully. In health research, it gives a clearer picture of survival when some participants are lost to follow-up or die from causes unrelated to the study.

This method works by dividing the study period into set intervals, usually one year. That makes it useful for tracking outcomes over time, especially in studies with early deaths after a high-risk surgical procedure. In one example, a two-year study follows two groups. One group is observed for one year, and the other is observed for two years.

The one-year survival rate is found from the starting group size and the number of deaths during that year. In the example, 1,000 patients begin in each group. The first group has 240 deaths in the first year, and the second group has 200 deaths in the first year. Using the actuarial calculation, the one-year survival rate is 78%.

The same method can also be used for long-term studies, such as testing how well a cancer treatment works over several years. It accounts for patients who are not followed for the full study or who die from unrelated causes. That makes the survival estimate more realistic when individual tracking is difficult.

Two-year survival uses conditional probability, which means the second year is calculated only for people who survived the first year and were observed for the full two years. In the example, the second-year survival probability is multiplied by the first-year survival probability. The result is 0.78 times 0.98, or 76.44%.

A two-year survival rate should not be higher than the one-year rate. The method is powerful, but it depends on complete follow-up and accurate death records. Even with those limits, it is especially useful in large population studies where following each person closely is not practical.

Life Table Method for Survival Rates

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actuarial approach

The life table method, also called the actuarial approach, is used to estimate survival rates in clinical and population studies. It began in life insurance, where risk over time must be measured carefully. In health research, it gives a clearer picture of survival when some participants are lost to follow-up or die from causes unrelated to the study. This method works by dividing the study period into set intervals, usually one year. That makes it useful for tracking outcomes over time,...

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key terms and concepts

Learn how the life table method, or actuarial approach, estimates one-year and two-year survival rates while accounting for follow-up losses and unrelated deaths.

Life Table Method for Survival Rates | JoVE K12

statistics

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Life Table Method for Survival Rates

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