Evaluating the prognostic role of the albumin-bilirubin and albumin-bilirubin-platelet scores in patients with pulmonary arterial hypertension

Background The albumin-bilirubin (ALBI) score and its modification with the addition of platelet count (ALBI-PLT) have been used as prognosticators in heart failure and liver diseases. However, the potential utility of these scores in pulmonary arterial hypertension (PAH) remains to be determined. In this study, we aimed to assess the prognostic value of the ALBI and ALBI-PLT scores in PAH. Methods The study population comprised 373 patients with PAH who were enrolled in our single-center study. Clinical, echocardiographic, and hemodynamic measures, along with multiparametric risk scores (MRS), including REVEAL 2.0, REVEAL 2.0 Lite, COMPERA, and FPHN models, as well as ALBI and ALBI-PLT scores, were used for risk prediction. The ALBI score was calculated using the following formula: ALBI score=(log₁₀total bilirubin[μmol/L]×0.66)+(albumin[g/L]×−0.085)ALBI score = (log₁₀ total bilirubin [μ mol/L] × 0.66) + (albumin [g/L] × -0.085)ALBI score=(log10total bilirubin[μmol/L]×0.66)+(albumin[g/L]×−0.085) ALBI grades were defined as follows: Grade 1: ≤−2.60; Grade 2: >−2.60 to −1.39; Grade 3: >−1.39. The ALBI-PLT score was calculated by adding the ALBI grade (1–3 points) and the platelet count score (1 point for >150×10⁹/L; 2 points for ≤150×10⁹/L). Results Low ALBI versus high ALBI was significantly associated with younger age, lower WHO FC class, longer 6MWD, lower BNP levels, higher pulse oximetry O₂ saturation, better right ventricular function, lower frequency of D-shaped septum and pericardial effusion, smaller IVC diameter in echocardiographic assessment, lower right atrial pressure, and higher cardiac index in right heart catheterization (p<0.05 for all). Low ALBI was also significantly related to a lower risk status according to the MRSs (p<0.001 for all). Kaplan-Meier survival estimates showed that low ALBI versus high ALBI, and ALBI-PLT 2 versus ALBI-PLT 3 or 4, were associated with significantly higher survival rates (p<0.001). In two Cox regression models adjusted for the baseline REVEAL 2.0 score, high ALBI versus low ALBI (hazard ratio [HR] 1.51, 95% CI: 1.06–2.15, p=0.023) and ALBI-PLT score 3 (HR 1.80, 95% CI: 1.20–2.71, p=0.005) or 4 (HR 2.13, 95% CI: 1.18–3.87, p=0.013) versus ALBI-PLT score 2 were associated with an increased risk of mortality. However, when comparing model metrics, the ALBI score demonstrated superior predictive accuracy. Conclusion Our findings suggest that both the ALBI and ALBI-PLT scores are valuable tools for risk stratification in PAH patients. However, the ALBI score outperforms the ALBI-PLT score in terms of predictive accuracy.