POS0999 HIGH CORRELATIONS BETWEEN QUESTION 1 &amp; 2 OF THE BASFI: AN OPPORTUNITY TO STREAMLINE THE BASFI
Authors: M. Maclean, S. Maguire, F. B. O’shea
Journal: Annals of the Rheumatic Diseases (2021)

Background: The Bath Ankylosing Spondylitis Functional Index (BASFI) is a useful tool to quantitatively characterise functional ability in a patient with axial spondyloarthropathy (axSpA). Whether first presentation, decompensated, or routine follow-up, BASFI can help establish a more accurate understanding of disease progression, or response. As with any questionnaire, relevance and absence of redundancy is required. This analysis questions the redundancy of the first two questions of the BASFI: 1) How difficult is it to put socks on your feet? 2) How difficult is it to pick a pen up off the floor? Objectives: To compare variation in reporting of questions one and two of the BASFI, to establish redundancy or exclusivity of these questions. Methods: IBM SPSS version 26 was used for data analysis. Data from axSpA patients who attended the Rheumatology department during the study period were included in the analysis where BASFI scores were available. Both variables (pen scores and sock scores) were assessed with a Shapiro-Wilk’s test for normal distribution. The variables were also assessed for the presence of a monotonic relationship by visual inspection of a scatterplot of the variables. Once a monotonic relationship was established a Spearman’s rank order correlation between the sock score and pen scores for each participant was analysed. Results: In total data from 82 axSpA patients were included in this analysis. Population was made up of 28% (23) females, 72% (59) males with mean BASDAI score 4.33 and mean BASFI score 3.88(Table 1). Both variables were not normally distributed as assessed by Shapiro-Wilk’s test (p &lt;0.05) necessitating a Spearman’s rank-order correlation for analysis. Preliminary analysis variables demonstrated the relationship between the variables to be monotonic as determined by visual inspection of the scatterplot (graph 1) with no outliers detected. There was a statistically significant, strong positive correlation between sock scores and pen scores in this axSpA population, r partial (80) =0.809 significant at the p &lt; 0.01 level. Table 1. Descriptive output of data % (n ) n 82 Females 28% (23) Males 72% (59) Age 45.03 BASDAI 4.33 BASFI 3.88 Pen score 3.93 Sock score 2.88 Sock score greater 7.3% (6) Pen score greater 50% (41) Same scores 42.7% (35) Conclusion: There is a strong positive correlation between sock (question 1) and pen scores (question 2) as captured by the BASFI. It appears that both questions are capturing a similar functional limitation in patients with axSpA. In order to minimise redundancy and improve the relevance of the BASFI our results support the removal of one of these questions to simplify the BASFI. From a practical perspective, putting on socks (question 1) would be a more commonly encountered daily activity than picking up a pen from the floor(question 2). As such, we would suggest removal of question 2 from the BASFI. Table 1 &amp; Figure 1 Graph 1. Spread of Data points demonstrating a monotonic relationship with no outliers Disclosure of Interests: Michael MacLean: None declared, Sinead Maguire Grant/research support from: Recipient of the Gilead Inflammation Fellowship, Finbar Barry O’Shea: None declared.