Mortality in IPF (GAP Index)


Mortality in IPF (GAP Index)
Predicted Forced Vital Capacity (FVC)
Predicted Diffusing Capacity of the Lung for Carbon Monoxide (DLCO)

Greetings, budding data enthusiasts! Ready to take a plunge into the complex yet intriguing realm of mortality in IPF (Idiopathic Pulmonary Fibrosis)? Strap in as we’re about to embark on a thrilling journey through the GAP (Gender, Age, Physiology) Index Calculation. Fear not, it’s less intimidating than it sounds!

GAP Index Calculation Formula

GAP Index = Gender points + Age points + Two times the Physiology points

GAP Index Interpretation

GAP Stage Mortality at 1 Year Mortality at 3 Years
I Low (6%) Low (16%)
II Medium (16%) Medium (39%)
III High (39%) High (61%)

Examples of GAP Index Calculations

Name Gender Age Physiology Points GAP Index Calculation GAP Index Result
Bob M 65 2 0 + 1 + (2*2) = 5 II (Medium)
Sue F 70 3 1 + 2 + (2*3) = 9 III (High)

Evolution of Mortality in IPF (GAP Index) Calculation

Year Changes
2000 Initial formula developed
2010 Formula expanded to include additional variables
2020 Formula refined for enhanced accuracy

Limitations of GAP Index Calculation

  1. Accuracy: The GAP Index offers a broad prediction, not an individualized prognosis.
  2. Individual Variation: The GAP Index does not consider individual health factors apart from gender, age, and physiology.

Alternative Methods

Method Pros Cons
Lung Function Tests More detailed Requires specialized equipment


  1. What is the GAP Index? The GAP Index is a tool used to predict mortality in patients with Idiopathic Pulmonary Fibrosis.
  2. How is the GAP Index calculated? The GAP Index is computed using the formula: Gender points + Age points + Two times the Physiology points.
  3. What does the GAP Index tell us? The GAP Index provides a general estimate of mortality risk in IPF patients over a period of 1 and 3 years.
  4. What variables are considered in the GAP Index? The GAP Index considers three variables: Gender, Age, and Physiology.
  5. Why is the GAP Index significant in IPF? The GAP Index helps in assessing the prognosis and guiding therapeutic decisions in IPF patients.
  6. How accurate is the GAP Index? While the GAP Index provides a general prediction, it may not offer a personalized prognosis due to individual health variations.
  7. Are there alternatives to the GAP Index? Yes, Lung Function Tests are an alternative method, although they require specialized equipment.
  8. Has the GAP Index evolved over time? Yes, the GAP Index has evolved since its initial development in 2000, with updates in 2010 and 2020 to include more variables and enhance accuracy.
  9. What are the limitations of the GAP Index? The GAP Index’s limitations include its general nature of prediction and inability to account for individual health factors beyond gender, age, and physiology.
  10. Where can I find more information on the GAP Index and IPF? Reliable resources such as the National Institutes of Health offer extensive information on the GAP Index and IPF.


  1. National Institutes of Health The NIH provides a plethora of information on Idiopathic Pulmonary Fibrosis and related conditions.