Analyses strategy, according to country groups
| Group | Country | GNI per capita $ | CF population | Age composition at base year | Method used for estimating age composition by year 2025 |
| A | Belgium, Czech Republic Denmark, France, UK, the Netherlands | 24 000–41 000 | Observed | Observed | Forecast, flow method in each country |
| B | Germany, Hungary, Ireland, Israel, Latvia, Moldova, Serbia, Sweden, Slovenia, Slovakia | 3 000–39 000 | Observed | Observed | Forecast, flow method using the weighted mean of flows calculated for countries of group A |
| C | Austria, Switzerland, Cyprus, Spain, Finland, Greece, Italy, Luxembourg, Malta, Portugal | 23 000–53 000 | Calculated using general population data and CF prevalence | Estimated assuming mean proportion of adults observed in countries of group A: 48.8% of adults | Projection, on the assumption of the weighted mean growth rates of group A countries: increase by 20% in children and by 78% in adults |
| D | Estonia, Lithuania, Poland, Russian Federation | 18 000–20 000 | Calculated using general population data and CF prevalence | Estimated assuming 25% of adults | Projection, scenario 1: increase by 20% in children and by 78% in adults; scenario 2: increase by 40% in children and by 40% in adults |
| Bulgaria, Belarus, Romania, Ukraine | 7 000–16 000 | Estimated assuming 15% of adults |
Country groups were defined as follows, group A: contributing data to the ECFS Patient Registry, coverage ≥85% of the cystic fibrosis (CF) population, longitudinal data linked at the patient level in the ECFS Patient Registry for at least 4 years. Group B: contributing data to the ECFS Patient Registry, coverage ≥85% of the CF population, longitudinal data for <4 years or no longitudinal data. Group C: not contributing data to the ECFS Patient Registry or <85% coverage of the CF population and gross national income (GNI) per capita ≥$23 000. Group D: not contributing data to the ECFS Patient Registry or coverage <85% of the CF population and GNI per capita <$23 000. The GNI per capita was based on purchasing power parity in current international dollars ($).