Causes of Death in Sickle Cell Disease Adult Patients: Old and New Trends
Authors: Ngo Stéphanie , Bartolucci Pablo , Lobo David , Mekontso-Dessap Armand , Gellen-Dautremer Justine , Noizat-Pirenne France , Audard Vincent , Godeau Bertrand , Galacteros Frédéric , Habibi Anoosha 
Published: November 2019

Abstract
Introduction: The treatment of sickle cell disease has advanced in recent years. Infant mortality has decreased with the introduction of systematic antibiotics, the preventive care cerebral vasculopathy and therapeutic education for families. It seemed interesting to update causes of death in adult sickle cell patients.
Materiel and method: We retrospectively reviewed the records of patients treated in our national referral center (Henri Mondor Hospital) which died between January 2001 and 2013. Basic biological parameters, chronic and acute complications present in these patients as well as their treatment, median age at death, causes and circumstances of death were identified when the information was available.
Results: During the study period, 96 patients among 2478 patients followed died. The median age at death was 36 years (mean age 37.1 + / - 10.6 years) (range: 16-69 years). The main characteristics of the population are summarized in Table 1. Abstract 2716. Table 1:General characteristics of patients during study periodSickle cell diseaseSSSCSβ0thal.Sβ+thal.TotalNumber1556670871532478Deaths71176296Mean age (years)35.1944.474130.537.1Sex ratio0.970.7210.95Mean Hemoglobin level (g/dl)8.711.68.911.59.3Mean LDH level (UI/ml)389.6229.9346.8250392.16Patients with treatment n (%)45 (63.4%)2 (11.8%)3 (50%)0 (0%)50 (52%)Transfusion program n (%)26 (36.6%)0 (0%)2 (33.3%)0 (0%)28 (29.2%)Hydroxycarbamide n (%)27 (38%)1 (5.9%)3 (50%)0 (0%)31 (32.3%)Erythropoietin n (%)18 (25.4%)1 (5.9%)0 (0%)0 (0%)19 (19.8%)Mean number of complication per patient (among 4)2.431.712.331.52.28
An offset to the right of population curves is observed compared to 10 years ago. (Figure 1)
Main causes of death were: acute organ failure in a context of chronic organ impairment (22.9%), acute chest syndrome (16.7%), infection (16.7%), cerebral hemorrhage (10.4%), drug overdose (7.3%), acute right heart failure (5.2%) and delayed hemolysis transfusion related (4.2%). Six deaths occurred during pregnancy. History of chronic kidney failure (p = 0.01) and positive irregular antibodies (p = 0.04) appeared to be a risk factor for premature death. A trend was noted for history of heart disease (p = 0.07) and a history of delayed hemolysis transfusion related (DHTR) (p = 0.13).
Discussion: The median age of death does not seem to improve since the study published by Platt et al (Mortality in sickle cell disease. Life expectancy and risk factors for early death. Platt OS,N Engl J Med. 1994 Jun 9;330(23):1639-44.); however our cohort appears to age, we observed an increase in the number of patients aged over 45. The causes of death have evolved compared to data available from previous studies, chronic organ failures are the leading cause of mortality especially in patients with renal impairment. The prevention of the onset of these complications is one of the new challenges especially renal diseases which were associated with premature mortality. DHTR and brain hemorrhages are new entities probably previously under-diagnosed. Pregnancy remains a risk period, which should strengthen its monitoring.
Figure 1: Patients’ age evolution between 2000 and 2011. Figure 1:. Patients’ age evolution between 2000 and 2011.

Disclosures
No relevant conflicts of interest to declare.