Pulmonary Arterial Hypertension in Kazakhstan: Clinical Characteristics, Survival, and Prognostic Value of COMPERA 2.0

Background: Clinical and survival data on pulmonary arterial hypertension (PAH) from Central Asia remain limited. This study aimed to characterize the clinical profile, survival outcomes, and prognostic value of baseline COMPERA 2.0 risk stratification in patients with PAH in Kazakhstan. Methods: This retrospective observational study included 206 adult patients with right heart catheterization-confirmed PAH hospitalized at the largest pulmonary hypertension referral center in Kazakhstan between 2020 and 2024. Patients were categorized into idiopathic PAH (IPAH), congenital heart disease-associated PAH (CHD-PAH), and other PAH subgroups. Kaplan–Meier survival was assessed from the index hospitalization, and Cox regression used patients with complete data for the variables included in each model. The multivariable model included 182 patients (39 deaths). Baseline risk stratification was assessed retrospectively using the COMPERA 2.0 four-strata model. Results: Etiological groups comprised 121 (58.7%) with IPAH, 73 (35.4%) with CHD-PAH, and 12 (5.8%) with other forms of PAH. The mean age was 39.5 ± 13.7 years, and 80.6% were female. At baseline, 62.6% were classified as WHO functional class III–IV. Overall survival did not differ significantly according to PAH etiology (log-rank p = 0.407). Baseline COMPERA 2.0 four-strata risk stratification differentiated survival (log-rank p < 0.001). In multivariable Cox regression analysis, baseline COMPERA 2.0 four-strata risk category remained associated with mortality (overall p = 0.006), with an adjusted HR of 4.67 (95% CI 1.22–17.86) for high-risk versus low-risk patients. Higher tricuspid annular plane systolic excursion (TAPSE) was independently associated with lower mortality hazard (HR 0.89 per mm increase, 95% CI 0.8–0.99; p = 0.026). Conclusions: In this hospitalized, single-center cohort from Kazakhstan, patients were predominantly young women with advanced functional impairment at baseline. Baseline COMPERA 2.0 four-strata risk assessment and lower TAPSE were associated with mortality after multivariable adjustment. These findings support multidimensional risk assessment in patients with PAH and highlight the need for prospective regional PAH registries.