In a long-term analysis, researchers evaluated mortality rates among patients with beta-thalassemia and pulmonary arterial hypertension (PAH) who had right heart catheterization. Results of this analysis were recently reported in the journal Blood.
The analysis was a long-term follow-up of a study (ClinicalTrials.gov Identifier: NCT01496963) that had previously estimated a prevalence rate of 2.1% for PAH in a population of patients with beta-thalassemia. The long-term follow-up analysis examined mortality rates for the patients with PAH in this study. Included patients were adults with beta-thalassemia major or intermedia.
In the original study, based on calculations of systolic pulmonary artery pressure (sPAP), patients had been grouped by probability of having pulmonary hypertension, and most with likely pulmonary hypertension underwent right heart catheterization. PAH was confirmed in 27 patients, 24 of whom were included in the follow-up analysis. In this follow-up analysis, mortality outcomes and multiple patient demographic and clinical data were evaluated.
The median age of evaluated patients in the long-term analysis was 46.5 years (IQR, 39.3-59). Patients had a median follow-up time of 4 years (IQR, 1-6), and a median survival time of 9 years.
With 13 fatalities during observation, the all-cause crude mortality rate was estimated to be 54.2% (95% CI, 32.9-74.5). A total of 10 fatalities were considered attributed to PAH, resulting in a PAH-related crude mortality rate of 41.7% (95% CI, 22.1-63.4). Cumulative PAH-related mortality-free survival rates were estimated to be 78% at 1 year, 65% at 2 years, and 60% at 5 years.
Most baseline demographic and clinical data comparisons revealed no statistically significant differences between patients who died from PAH and patients who did not. However, the median absolute change in sPAP differed between patients who died from PAH (+6.5 mm Hg) and patients who did not (-21.6 mm Hg; P =.024). Relative changes in sPAP also significantly differed between patients who died from PAH (+8.2%), compared with those who did not (-31.6%; P =.010). In a receiver operating characteristic curve analysis, relative change in sPAP appeared predictive of PAH-related mortality (area under the curve, 0.875 + 0.085; P =.011).
PAH-related therapy was used by 21 patients following PAH diagnosis, and the crude mortality rate was estimated to be 38.1% among those treated with PAH-related therapy. Crude PAH-related mortality rates, cumulative 5-year PAH-free mortality-free survival rates, and median relative changes in sPAP were compared across PAH-related treatment approaches, including lack of treatment, single-agent therapy, and double-agent therapy approaches. Statistically significant differences were not seen in these comparisons, but mortality rates appeared numerically lower with treatment.
“Although this study was not designed to evaluate the impact of therapy on PAH-related mortality, improvement in sPAP with the use of pharmacologic agents was associated with a lower mortality rate, especially for patients achieving >25% reduction from baseline,” the study investigators wrote in their report. They indicated more research is needed to evaluate survival trends with PAH-targeted treatment.
Pinto VM, Musallam KM, Derchi G, et al; on behalf of the Webthal project. Mortality in b-thalassemia patients with confirmed pulmonary arterial hypertension on right heart catheterization. Blood. 2022;139(13):2080-2083. doi:10.1182/blood.2021014862