Do urological symptoms cluster among women? Results from the Boston Area Community Health Survey

OBJECTIVES: To conduct a cluster analysis of urological symptoms among women in the Boston Area Community Health (BACH) Survey, to describe the distribution of urological symptoms within each cluster, and to determine whether comorbidities, demographic characteristics, and lifestyle factors were associated with cluster membership. SUBJECTS AND METHODS: The BACH Survey is a racially and ethnically diverse random sample (3205 women) of community-dwelling residents of Boston, MA, USA, aged 30-79 years. Fourteen urological symptoms measured by participant self-report (using previously validated scales) were included in this analysis. Cluster analyses were conducted using hierarchical and non-hierarchical (k-means) methods. Within clusters, demographic characteristics, risk factors for urological symptoms and the interference of symptoms with daily activities were also assessed. RESULTS: Three-quarters of the sample reported at least one urological symptom; four symptom clusters were identified. Most symptomatic women (54%) were assigned to Cluster 1, which was characterized by storage symptoms (nocturia and urinary frequency) with an accompanying low prevalence of other urological symptoms; a second cluster was distinguished by frequency symptoms. Clusters 3 and 4 were characterized by a high prevalence of urinary incontinence and had increased interference scores and more symptoms overall (including voiding and post-voiding symptoms) than the other two clusters. Cluster 4 (8% of symptomatic women) was characterized by a high prevalence of nearly all urological symptoms and the highest interference score. In this most symptomatic cluster, body size and waist circumference were markedly higher, as was the prevalence of diabetes, hypertension and cardiovascular disease than in the other cluster groups or asymptomatic women. Women in Cluster 4 were more likely to be surgically menopausal, or to have had other forms of urogynaecological surgeries than women in the other clusters. CONCLUSION: Four distinct clusters of urological symptoms were identified among symptomatic women in the BACH Survey, two of which had a high prevalence of urinary incontinence. These cluster patterns provide a novel, empirically-based framework for investigating aetiological mechanisms and management outcomes for common urological symptoms in women.