Bladder Pain Syndrome/Interstitial Cystitis (BPS/IC) is a chronic pelvic pain condition characterized by bladder-related pain and lower urinary tract symptoms that can interfere with daily activities and lead to pain-related disability(1, 2). Although factors associated with pain-related disability in BPS/IC have been investigated, they have not been systematically evaluated within an International Classification of Functioning, Disability, and Health (ICF) framework yet. Therefore, this study aimed to identify factors associated with pain-related disability in women with BPS/IC using an ICF framework.

This cross-sectional study included 42 women with BPS/IC. Pain-related disability was assessed using the Pain Disability Index (PDI). 
Within the ICF framework, body functions and structures included pain intensity and symptom severity, assessed using a Visual Analog Scale (VAS) and the Interstitial Cystitis Symptom and Problem Index (ICSI/ICPI), respectively, as well as 3-day bladder diary parameters (i.e. frequency, nocturia, mean voided volume) and self-reported sleep disturbance. 
Activity limitations and participation restrictions included physical function, role limitations due to physical problems, and social functioning, assessed using relevant Short Form-36 (SF-36) subscales. 
Personal factors included pain catastrophizing, self-efficacy, and anxiety/depression, assessed using the Pain Catastrophizing Scale (PCS), Pain Self-Efficacy Questionnaire (PSEQ), and Hospital Anxiety and Depression Scale (HADS), respectively. The presence of other chronic pain conditions and psychological diseases was also recorded. 
As this was a pilot study, a sample size calculation was not performed. Associations were analyzed using Spearman correlation and Mann–Whitney U tests. The level of statistical significance was set at 0.05. Variables with p<0.20 were entered into a multivariable linear regression model using backward elimination.

A total of 42 women (mean age=47.0±13.3 years; Body Mass Index=25.9±4.8 kg/m²) were included in this study. 
Regarding body functions and structures variables, pain intensity (r=0.343, p=0.026) and symptom severity (r=0.364, p=0.019) were moderately associated with pain-related disability. On the other hand, bladder diary parameters and the presence of sleep disturbance were not significantly associated with pain-related disability (p>0.05). 
Regarding activity limitations and participation restrictions, role limitations due to physical problems showed a moderate association with pain-related disability (r=-0.502, p=0.001). In contrast,  physical and social functioning were not significantly associated with pain-related disability (p>0.05).
Regarding personal factors, pain catastrophizing (r=0.449, p=0.003) and pain self-efficacy (r=-0.354, p=0.021) were moderately associated with pain-related disability, whereas no significant associations were found with levels of anxiety and depression, the presence of other chronic pain conditions, or the presence of psychological disorders (p>0.05).
In the multivariable model, role limitations due to physical problems (β=-0.501, p=0.002) and pain catastrophizing (β=0.364, p=0.016) were independently associated with pain-related disability, explaining 43.4% of the variance (adjusted R²=0.434).

In this analysis, although multiple factors across the categories of the ICF framework were associated with pain-related disability, only pain catastrophizing and role limitations due to physical problems remained independently associated in the multivariable analysis.
These findings suggest that pain-related disability in women with BPS/IC may be more strongly associated with activity limitations and personal factors than with impairments related to body functions and structures. Previous studies have emphasized the role of psychosocial factors in disability among women with BPS/IC (2); this study extends this perspective by demonstrating the independent contributions of both activity limitations and pain-related cognitive factors.

To our knowledge, this is the first study to investigate factors associated with pain-related disability in women with BPS/IC within an ICF framework. We found that pain catastrophizing and role limitations due to physical problems were associated with pain-related disability. These findings suggest that pain-related cognitions and activity limitations should be considered in clinical management and rehabilitation. Further large-scale longitudinal studies incorporating objective measures are needed to evaluate factors associated with pain-related disability within the ICF framework.

Doggweiler, R., Whitmore, K. E., Meijlink, J. M., Drake, M. J., Frawley, H., Nordling, J., Hanno, P., Fraser, M. O., Homma, Y., Garrido, G., Gomes, M. J., Elneil, S., van de Merwe, J. P., Lin, A. T. L., & Tomoe, H. (2017). A standard for terminology in chronic pelvic pain syndromes: A report from the chronic pelvic pain working group of the international continence society. Neurourology and urodynamics, 36(4), 984–1008. https://doi.org/10.1002/nau.23072
Katz, L., Tripp, D. A., Nickel, J. C., Mayer, R., Reimann, M., & van Ophoven, A. (2013). Disability in women suffering from interstitial cystitis/bladder pain syndrome. BJU international, 111(1), 114–121. https://doi.org/10.1111/j.1464-410X.2012.11238.x