Introduction: Lower urinary tract symptoms (LUTS) are an independent risk factor for falls and fractures. In clinical practice, frail older LUTS patients sustain falls and fractures caused by their activities of daily living. This often leads to life-threatening events from the progression of weakness. Although LUTS per se may sometimes be a vital prognostic factor, there have been no clinical studies to predict fractures in LUTS patients. The World Health Organization developed the Fracture Risk Assessment Tool (FRAX) as “a tool for calculating the risk of fractures over the next 10 years.” FRAX is a 12-item fracture prediction screening tool that includes age, sex, smoking cessation, history of steroid therapy, comorbidities, and history of fractures that can be calculated. It is also useful for screening for hip and major fractures, not only for those with osteoporosis but also for healthy patients. Our study aimed to estimate the risk of fracture in patients with overactive bladder (OAB) using FRAX, particularly those with LUTS, and to investigate the association between individual OAB symptoms and fracture risk. Methods: Subjects with de novo OAB and age-matched controls were enrolled, and between-group differences in bone fracture risk using the FRAX were analyzed. Severity assessment was performed using the OAB symptom score (OABSS), with OAB patients scoring =2 on item Q3 (urgency) and a total of =3. Bone fracture risk was analyzed in cases grouped based on OAB severity (non-OAB, mild-OAB [OABSS=5) and moderate/severe-OAB [OABSS=6]). Results: This study included 324 patients: 122 in the OAB (O) group and 202 in the non-OAB (N) group. The O group had significantly higher major fracture risk in the next 10 years (O: 19.5±13.2%; N: 11.7±10.3%; P<0.001), and risk of hip fracture (O: 8.8±8.9%; N: 4.8±8.0%; P<0.001) than the N group. All four question items on OABSS and the total scores were significantly positively correlated with the risk of major fractures. Q2 (nocturia) was the most strongly correlated (r=0.401, P<0.001). The relationship between risk of hip fracture and OABSS was similar (Q2: r=0.372, P<0.001). The moderate/severe-OAB group had the highest risk of major fractures (non-OAB: 11.7±10.3%; mild-OAB: 15.5±10.9%; moderate/severe-OAB 21.5±13.9, P<0.001), and the risk of hip fracture (non-OAB: 4.8±8.0%; mild-OAB: 6.5±7.2%; moderate/severe-OAB: 10.0±9.5, P<0.001) was the highest. Conclusions: OAB patients had a higher fracture risk than non-OAB patients, and the risk of fracture was also associated with the severity of OAB. SOURCE OF Funding: None.
