(265) Predicting Exacerbation in the Adult Patient with Cystic Fibrosis Using a 1-Minute Sit to Stand Test

Background: Forced expiratory volume (FEV1) is typically utilized in the cystic fibrosis (CF) patient population to measure disease severity, progression, and therapeutic efficacy. Patients with CF typically have exercise intolerance; therefore, exercise testing is imperative to monitor for physical limitations and potential adverse reactions. Other outcome measures such as CPET and the 6MWT have been previously utilized, but they require significant resources. Our aim of this quality improvement project was to determine if there are statistically significant correlations between changes in FEV1 or percent predicted FEV1 (ppFEV1) and the 1-minute sit to stand (1MSTS) test outcomes.

Methods: Patients with CF or CF-like diseases who regularly attend Yale New Haven’s Adult CF Clinic were selected to participated in the 1MSTS. Each patient was educated on the appropriate procedure. Information including age, sex, FEV1, ppFEV1, pre-heart rate, and pre-oxygen saturation was obtained. The patients then performed as many sit to stands possible in 1 minute time period with heart rate and oxygen saturations recorded at the 30 second mark and upon completion of the test. The total number of sit to stands was recorded along with rest breaks, subjective comments, and adverse events.

Results: Data was collected over 2 years in CF clinic. Sixty-six patients with CF and CF-like disease completed both 1MSTS and PFTs during the clinic visit. Replicate values represent patient data collected at separate clinic visits; final N=109. One patient experienced desaturation to 89%; recovered at rest without additional interventions. There were no reports or syncope, chest pain, nausea, vomiting, orthopedic injury or exacerbation of pulmonary symptoms. We found performance in 1-minute STS significantly predicted FEV1 (r=0.28, p< 0.01) and ppFEV1 (r=0.22; p< 0.05). Simple liner regression was used to test if 1-minute STS significantly predicted FEV1. The fitted regression model was FEV1=5.82+3.173*(STS). The overall regression was statistically significant (R²=0.078, F(1,107)=9, p< 0.01). It was found that performance of STS significantly predicted FEV1 (β=11.71, p< 0.01). Simple liner regression of 1-minute STS did not significantly predict ppFEV1. Sub-group analysis for age, gender, and FEV1 >40% are ongoing.

Conclusions: The 1MSTS test was integrated successfully in CF clinic visits through a combination of spirometry and physical therapy assessment. There is a weak correlation between performance in 1MSTS to FEV1 and ppFEV1. Limitations include variations in administration of the 1MSTS, patient effort, and coordination of PFTs with clinic visit. Sub-group analysis will investigate the strength of correlation between 1MSTS and FEV1 when age, sex or baseline FEV1 are controlled. Despite needing to continue to analyze these associations, this quality improvement project has established that the 1MSTS test is time-efficient, safe, cost-effective, and feasible to administer. This test could assist CF clinic centers in obtaining insight into a patient’s tolerance for exercise as well as the need for further interdisciplinary team evaluation. Also, amidst a global pandemic where telehealth has become a regular means of patient-provider interactions, the 1MSTS test could be helpful in providing objective data, when PFTs may not be accessible, as it can be administered through video.

Acknowledgements: This work was supported by OUTRun38; YNHH Inpatient Rehab Services; Yale University; and CFF.

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