Validity of Functional Status and Pain Assessment Scale in Hospitalized Adult SCD Patients
Authors: Sop Daniel M , Guy Margaret , Qayyum Rehan , Zhang Yue , Smith Wally R 
Published: June 2024

Abstract

Presentation Date: 6/9/2024
Presentation Start Time: 3:00:00 PM

Background
Despite the prevalence of hospitalization in Sickle Cell Disease (SCD) due to pain and Vaso-Occlusive Crisis (VOC), there are no validated measures to evaluate either urgent likelihood or necessity for hospitalization for SCD VOC, or discharge appropriateness. The prevailing Numeric Rating Scale (NRS) for pain intensity (0-10), though widely used, is limited by its unidimensional nature and susceptibility to confounding by environmental, psychosocial, economic, and access-related variables. Given the intricate interplay between pain intensity, daily functional status, and hospitalization, a nuanced understanding of this interplay would improve care, and could potentially improve predictability of hospital use. In prior research we demonstrated face, construct, discriminant, and preliminary convergent validity of the newly developed, 10-item Functional Status Pain Assessment (FSPA) scale (0-50) in adult SCD patients hospitalized with VOC (Blood, 2019). We aimed in this study to further demonstrate criterion validity of the FSPA, this time against changes in hospital length of stay as well as fluctuations in pain intensity measured by the NRS. Furthermore, we aimed to assess the capacity of FSPA scores, compared with unmeasured (presumably psychosocial) variables, to predict hospital length of stay (LOS).

Methods
We studied 561 assessments from 91 unique patients admitted on one SCD specialized nursing unit from January 2018 to June of 2019. We performed Principal Component Analysis (PCA) and built Partial Least Squares (PLS) models to explore the intricate relationship between LOS, pain intensity, and FSPA. Additionally, we built a Generalized Linear Model (GLM) to quantify the impact of changes in pain intensity on LOS. The significance level was p = 0.05.

Results
PCA revealed that neither admission nor discharge FSPA scores contributed significantly to changes in LOS. Specifically, no component or factor of FSPA score on day of admission explained the change in LOS. In addition, FSPA score on day of discharge explained only 5.69% of the change in LOS. Similarly, FSPA score explained only 19.66% of pain intensity on all days. Additionally, our assessment of the relationship between LOS and pain intensity changes from admission to discharge was not significant p = 0.92.

Conclusions
Contrary to our hypotheses, FSPA scores do not contribute to (does not demonstrate criterion validity to) changes in SCD LOS nor pain intensity changes. Furthermore, GLM changes in pain intensity from admission to discharge do not explain changes in LOS. These findings underscore the complexity of factors influencing hospitalization decisions in SCD patients, and confirm that unmeasured variables appear to exert a more substantial influence on hospital LOS than either pain intensity or daily pain function.
Percent Variation Accounted for Length of Stay and Pain Intensity by Principal Components from Functional Movement Score.