THE JOURNEY OF INCONTINENT WOMEN FROM COMMUNITY TO UNIVERSITY CLINIC - IMPLICATIONS FOR SELECTION BIAS, GATEKEEPER FUNCTION, AND PRIMARY-CARE

Background. The selection process of patients from community to hospit als may introduce bias into research and hamper the generalization of hospital-based research back to general practice. Objective. The objec tive of this study was to use female urinary incontinence as a model I n an attempt to provide empirical support fbr selection bias. Method. The analyses are based on three populations of incontinent women: comm unity level (epidemiological survey, 535 women), primary care level (g eneral practice, prospective clinical study, 105 women), and secondary care level (university hospital, prospective clinical study, 228 wome n). Results. The general practice patients were older and the hospital patients younger than those in the community. From community via gene ral practice to hospital, there was an increase in duration, frequency of leakage, amount of leakage, severity and perceived impact of incon tinence. Help-seeking at the primary care level was associated with in creasing age and severity, and with urge symptoms and substantial impa ct. Referral from general practice to hospital level was only associat ed with age and urge symptoms. Conclusion. The study provides empirica l evidence to support the existence of selection bias. This phenomenon must not be overlooked when recommendations developed at the consulta nt level are presented at a level with a significantly different clini cal picture of a condition.