Predictive factors for survival in sickle cell disease: A cohort study using ETENDARD data

ASH: 60th American Society of Hematology Annual Meeting & ExpositionL Savale, G Loko, F Lionnet, B Maitre, A Habibi, J Inamo, D Bachir, F Driss, V Audard, E Audureau, M Humbert, G Simonneau, F Galacteros, F Parent, P Bartolucci | December 01, 2018

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Summary: Researchers presented the updated, 10-year follow-up data from the ETENDARD cohort study, in which they analyzed overall survival in patients with sickle cell disease (SCD) according to tricuspid regurgitation velocity (TRV) and mean pulmonary arterial pressure (mPAP) status. They found that while an isolated VRT ≥ 2.5 m/s on transthoracic echocardiography may be a moderate prognostic factor for overall survival, outcomes varied greatly according to mPAP values. Thus, they concluded that only the combination of a VRT ≥ 2.5 m/s and an mPAP ≥ 25 mmHg was associated with a worse prognosis. This confirms the necessity of a right-sided heart catheterization (RHC) when pulmonary hypertension (PH) is suspected in patients with SCD.

Methods:

  • Researchers included 398 patients followed for a mean of 106 months, and divided them as follows:
    • Group A: patients with a TRV < 2.5 m/s;
    • Group B: patients with a TRV ≥ 2.5 m/s and mPAP < 25 mmHg; and
    • Group C: patients with a TRV ≥ 2.5 m/s and a mPAP ≥ 25 mmHg.
  • Using Kaplan-Meier, they constructed survival curves and compared them using log-rank testing.

Results

  • Researchers observed a TRV of ≥2.5 m/s in 109 patients (27.4%); RHC was performed in 98, confirming a PH diagnosis (mPAP ≥ 25 mmHg) in 24 (6%).
  • They found a significantly decreased overall survival in patients with a TRV ≥ 2.5 m/s (groups B/C vs A; HR: 2.5, 95% confidence interval: 1.3-4.7; P=0.006).
  • After they accounted for mPAP levels, however, researchers found no statistically significant difference between patients with a TRV < 2.5 m/s and those with TRV ≥ 2.5 m/s and mPAP < 25 mmHg (group A vs  B, log-rank P=0.54).
  • In patients with a TRV ≥ 2.5 m/s and a confirmed diagnosis of PH by RHC (mPAP ≥ 25 mmHg), they observed a significantly decreased survival in comparison with the two other groups (groups A/B vs C, P < 0.0001), which gave the following HRs in Cox analysis:
    • Group A: HR=1.0;
    • Group B: HR=1.3 (95% CI: 0.5-3.0, P=0.59); and
    • Group C: HR=6.0 (95% CI: 2.7-13.3, P < 0.0001).
  • Researchers noted that at baseline, patients with confirmed diagnosis of PH by RHC (group C) were older and characterized by lower 6-min walk distance, higher rate of leg ulcers, lower PaO2 and forced vital capacity, and higher levels of alkaline phosphatase, lactate deshydrogenase and gammaglutamyl transferase (all P < 0.05).
  • Further, they observed that creatinine clearance was significantly lower in both groups with TRV ≥ 2.5 m/s.
  • All these parameters and systemic arterial pressures at time of inclusion were associated with a higher risk of mortality in univariate analysis.

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