COMPERA 2.0. a refined four-stratum risk assessment model for pulmonary arterial hypertension

Background: Risk stratification plays an essential role in the management of patients with pulmonary arterial hypertension (PAH). The current European guidelines propose a 3-strata model to categorise risk as low, intermediate, or high, based on the expected 1-year mortality. However, with this model, most patients are categorised as intermediate risk. We investigated a modified approach based on 4 risk categories with intermediate risk subdivided into intermediate-low and intermediate-high risk. Methods: We analysed data from COMPERA, a European pulmonary hypertension registry, and calculated risk at diagnosis and first follow-up based on functional class (FC), 6 min walking distance (6 MWD) and serum levels of brain natriuretic peptide (BNP) or N-terminal fragment of pro-BNP (NT-proBNP), using refined cut-off values. Survival was assessed with Kaplan-Meier analyses, log-rank testing, and Cox proportional hazards models. Results: Data from 1,655 patients with PAH were analysed. Using the 3-strata model, most patients were classified as intermediate risk (76.0% at baseline and 63.9% at first follow-up). The refined 4-strata risk model yielded a more nuanced separation and predicted long-term survival, especially at follow-up assessment. Changes in risk from baseline to follow-up were observed in 31.1% of the patients with the 3-strata model and in 49.2% with the 4-strata model. These changes, including those between the intermediate-low and intermediate-high strata, were associated with changes in long-term mortality risk. Conclusions: Modified risk stratification using a 4-strata model based on refined cut-off levels for FC, 6MWD and BNP/NT-proBNP was more sensitive to prognostically relevant changes in risk than the original 3-strata model.