Sickle cell disease (SCD) is a severe inherited hemoglobinopathy that affects approximately 100,000 people in the United States . Survival has substantially improved over the last 50 years with median survival increasing from 14 years (Diggs, 1973), to approximately 40 to 45 years in population-based studies and 61 years in contemporary cohorts recruited at comprehensive programs [2–4]. Individuals with SCD experience a lifetime of sickling and microvascular occlusion that has an effect on every organ of the body . Adults with SCD experience frequent hospitalizations. Based on data from the Agency for Healthcare Research and Quality, individuals with SCD have 1.23 hospitalizations per patient per year for individuals age 46–64 and 0.72 hospitalizations per patient per year for individuals age ≥ 65 years . This is substantially more hospitalizations compared to the general non-SCD population, which is 0.11 hospitalizations per patient per year for individuals age 45–64 and 0.35 per patient per year for individuals age ≥ 65 .
Aging is defined as a deterioration in physiological function that occurs over time . Individuals with similar chronological age often vary in their functional age . Adults with SCD demonstrate substantial and early deterioration of multiple organ systems that leads to complications seen frequently in geriatric populations, such as cardiopulmonary complications, sensory deficits, and a decline in physical and cognitive function [10–12]. They are particularly at increased risk of lower extremity functional decline due to complications such as avascular necrosis of the hips often requiring surgical intervention .
SCD providers often use SCD complications, chronological age, laboratory data, healthcare utilization, and subjective measures of performance status to assess overall health and risk of adverse outcomes. In one of the few studies with multiple direct measures of physical function, adults with SCD had lower pulmonary function, grip strength, and functional capacity measured by six-minute walk test (6MWT) compared to predicted norms for age and gender . The 6MWT is the only physical functional assessment routinely used to assess patients with SCD. The Adult Sickle Cell Quality of Life Measurement System, ASCQ-Me℠, and Patient-Reported Outcome Measurement Information System, PROMIS®, are subjective measures that have been used to assess health and function in individuals with SCD . These measures are useful in that they do provide patient-reported data about important areas of health in adults with SCD such as sleep, pain, fatigue, and mental health. However, as individuals with SCD age, the current condition-specific assessment tools available are limited in their ability to capture both the SCD and age-related areas, such as objective measures of physical function, frailty, dependency, and polypharmacy.
There is a need for more comprehensive and objective measures of health and function that are tailored to the specific needs of older adults with SCD. These measures should be simple and brief enough to be easily integrated into a clinical setting. When selecting measures to include in an assessment, SCD-specific factors, such as acute and chronic pain, avascular necrosis (AVN) of the joints, early-onset of silent and overt strokes, pulmonary hypertension, and cultural differences require careful consideration. Assessment tools used for non-SCD older populations, like geriatric assessment are useful in assessing age-related conditions and functional decline; however, these measures have not been validated in adults with SCD. There is a need for validated assessment tools to evaluate aging adults with SCD in order to properly identify and address the unique issues in this population.
Geriatric assessment has been used to identify capabilities and vulnerabilities of older individuals by measuring physical function, cognitive function, psychological state, nutritional status, social support, comorbidities, and medications . Geriatric assessment is not only routinely used by geriatricians, but it has been widely used by oncologist to assess risk of toxicity and mortality related to chemotherapy. Interventions based on geriatric assessment have been shown to improve survival, preserve independence, and restore mobility [17, 18].
Our goal is to develop the first geriatric assessment for older adults with sickle cell disease (SCD-GA). Our rationale for developing SCD-GA is to create a standard method for assessing risk of adverse outcomes, address the unique needs of this growing population of older adults with SCD, and identify modifiable deficits to guide development of interventions to improve function and quality of life. We hope these interventions will reduce frailty and mortality. The measures included in this pilot study for the SCD-GA differ from the oncology geriatric assessment in that the oncology geriatric assessment only includes the Timed-Up-And-Go (TUG) and The Blessed-Orientation-Memory-Concentration (BOMC) Test as the only physical and cognitive measures . For the SCD-GA we included additional physical and cognitive functional measures to evaluate the early physical and cognitive decline that occurs in the SCD population [14, 19]. We also included several SCD-specific questions on healthcare utilization and SCD complications.
We found that it is best to use a multidisciplinary approach when selecting measures for the SCD-GA . The investigators are adult SCD clinicians collaborating with exercise experts and geriatricians from a Pepper Older Americans Independence Center (OAIC). This collaboration between SCD and geriatric specialists is a novel concept. SCD has historically been a disease of children and young adults until modern-day initiatives, such as penicillin prophylaxis reduced deaths from pneumococcal sepsis, newborn screening, and disease-modifying therapies, such as hydroxyurea improved survival. Now some individuals with SCD even becoming octogenarians [21, 22]. With the life expectancy for SCD improving and the rise in number of approved disease-modifying therapies, this collaboration will become increasingly vital for the care of aging adults with SCD.
Study aims and objectives
The aim of this study is to assess the feasibility of SCD-GA, by the proportion completing the assessment and consent, duration of the assessment, acceptability and adverse events. Our aim is also to assess the feasibility of repeat measures at different time points by performing the SCD-GA at steady state, post-hospitalization, and 12-months after the initial assessment. The results of this pilot study will be used to select measures to be included in the revised SCD-GA and to optimize the design of a multicenter validation study of this revised assessment. We also will develop interventions based on deficits identified by the SCD-GA.