The Sicklefit Exercise Program for Older Adults with Sickle Cell Disease: Feasibility, Acceptability, and Safety

Despite increases in the lifespan for adults with sickle cell disease (SCD), older adults with SCD experience progressive functional impairment. There is a critical need for interventions to maintain mobility and independence. To address this, we piloted SickleFit, an exercise program for older adults with SCD (age ≥ 40 years) adapted from Gerofit, a supervised personalized exercise program for older veterans (age > 65 years) shown to improve physical function, quality of life, mental health, social connectedness, and survival in veterans with chronic disease and/or impaired mobility.

Methods

We piloted SickleFit in 3 cohorts of 4-8 older adults with SCD from a single academic center. We excluded individuals with unstable cardiac disease, oxygen-dependence, moderate or severe cognitive impairment, and wheelchair-bound.

Participants engaged in virtual exercise via Zoom with workouts personalized for functional status. The program included moderate intensity cardio, strength training, balance, mobility, and mindfulness. The feasibility endpoint was for ≥ 80% of participants attend ≥ 50% of classes. The safety goal was no major or life-threatening adverse events (AEs) related to the intervention. Participants completed acceptability surveys. Exploratory outcomes included change in physical performance.

Results

We screened 80 older adults with SCD for eligibility and approached 45 people in clinic, 3 declined due to having their own exercise routine or a lack of interest in research, 3 were ineligible due to oxygen dependence, exertional chest pain, or uncontrolled arrythmia. Sixteen were interested but did not consent due to scheduling conflicts (8), full cohort (5), not at steady state (2), or recent surgery (1).

We consented 21 people and removed 1 for inability to complete the baseline assessment due weekly emergency department (ED) visits. Two participants completed baseline assessments but never started SickleFit due to schedule conflicts.

The first 3 cohorts included 18 participants analyzed for outcomes and AEs. Median age was 51 years (range 40-82), 67% women, and 39% severe genotype. Nearly half (44%) taking hydroxyurea, 44% long-acting opioids, and 56% short-acting opioids. Half (50%) had a history of joint damage (hip or shoulder), 33% joint surgery, and 39% hospitalized in the last year. Comorbidities included hypertension (28%), retinopathy (17%), and stroke (17%).

Most participants (78%) attended ≥ 50% of exercise classes with a median proportion of classes attended of 77% (IQR 64-82%). The feasibility endpoint was not met for 4 people (3 had scheduling conflicts and 1 missed multiple classes due to surgery).

There were 32 minor AEs (defined as pain or injury managed at home) with 3 related to the intervention and 8 possibly related. There were 23 major AEs (defined as pain or injury requiring ED, day hospital, or hospitalization) with 1 related to the intervention (upper body pain after resistance training requiring ED visit). There were no life-threatening adverse events.

Most (83%) completed the acceptability survey with 67% reporting 12-weeks as just right and 27% too short. Most (80%) reported 60-minute workouts as just right and 20% too long. Nearly all (93%) reported satisfaction with the program and 7% felt neutral. Almost all (93%) said it matched or exceeded their expectations for exercise and 7% felt it was worse than expected. Most (93%) rated their exercise outcomes as good or very good, 7% rated outcomes as fair. Nearly all (93%) described being pleased or delighted with their experience with regular exercise.

On physical performance testing, 86% improved usual gait speed (median change 0.07 m/s IQR 0.03-0.13), 79% improved Timed Up And Go (-1.1 sec IQR -2.2 - -0.2), 64% improved six-minute walk distance (22 meters IQR -5 -35), 36% improved 30-second chair stand (0 IQR -1.0 - 1.8), and 43% improved plank duration (1.0 second IQR 0 - 22).

Conclusion

This pilot study of SickleFit demonstrated it is safe and very enjoyable for older adults with SCD. Most AEs were unrelated to the exercise program and many participants chose to continue exercising by modifying activity or resting. Most participants met the feasibility endpoint and identified facilitators as virtual classes, accommodating times, and personalization of workouts based on functional status and SCD symptoms. Future studies will investigate how SickleFit improves function and quality of life for older adults with SCD.

Strouse:Editas: Consultancy; Takeda: Research Funding; GE Healthcare: Current equity holder in publicly-traded company; Disc Medicine: Membership on an entity's Board of Directors or advisory committees; Agios: Research Funding.