Clinical Course and Outcomes in Older Patients with Sickle Cell Disease at a Community Hospital

As life expectancy improves in Sickle Cell Disease (SCD), older patients acquire age-related co-morbid conditions that impact their quality of life. In addition, they continue to suffer from sickle-cell related organ dysfunction. In this retrospective analysis of SCD patients age ≥40 years, we compared rates of hospitalization, treatments utilized and prevalence of co-morbid conditions in the common sickle cell genotypes.

We conducted a retrospective study of patients with SCD, aged 40 years and older who were enrolled in the sickle cell clinic at our institution. Electronic health records over an 11-year period from 2011 to 2021 were reviewed for demographics, clinical and laboratory data and rates of hospitalization for acute sickle cell vaso-occlusive events. We utilized a feature of our electronic health record to also review hospitalization data from other hospitals in our region.

We identified 64 patients aged ≥40 years with SCD who followed in our clinic. The median age was 50.6 years (range 40 to 89 years). There was a predominance of female patients (75%). Ninety-two percent of the study patients were between 40 to 69 years, with 5 patients (8%) aged ≥70 years. Patient characteristics and results are summarized in Table 1. The hospitalization rate of patients with Hemoglobin (Hb) SS genotype was significantly higher than those of other genotypes. Furthermore, patients with higher rates of hospitalization and clinic visits were more likely to be on hydroxyurea. Twenty-three percent of patients in the cohort were on disease-modifying therapies such as voxelotor, and L-glutamine.

The prevalence of comorbid conditions and SCD complications are summarized in Table 2. Patients with comorbid conditions such as diabetes mellitus (DM), cancer, hypertension (HTN) and chronic kidney disease (CKD) had higher median ages than patients without those conditions. Variability in phenotypic expression of SCD has been observed even within the same genotype. We found that patients with HbSS had significantly more hospitalizations for acute sickle cell events than those with HbSC or HbSβ-thalassemia. We also observed that eleven patients (17%) had no hospitalizations for acute sickle cell events over the 11-year period reviewed. Of these, 55% were HbSC - while they had less hospitalizations for acute vaso-occlusive events, they suffered from chronic complications especially AVN.

The most common co-morbid conditions identified among this older cohort of patients with SCD was HTN (45%), followed by CKD (23%), venous thromboembolism (VTE) (16%), stroke (12.5%) and cancer (12.5%). Diabetes mellitus was present in 6% of older adults in this study. Whether DM might be underdiagnosed in SCD patients due to the reduced utility of HbA1c measurements in this population is a consideration. A history of VTE was reported more commonly in HbSC genotype than HbSS or HbSβ-thalassemia. Excluding pain crises, the most common SCD-related organ complication observed among all genotypes was Acute Chest Syndrome. Patients with the HbSS genotype had higher rates of sickle cell-related complications, except for avascular necrosis (AVN) of the hip which was most common in HbSC patients.

As further gains in life expectancy are made in individuals with SCD, age-related morbidities should be attentively recognized and addressed. Early recognition of any unfavorable interplay between the underlying sickling syndrome and coexisting chronic conditions should be a key component of managing older patients with SCD.

No relevant conflicts of interest to declare.