Incidence rates of erectile dysfunction in the Dutch general population. Effects of definition, clinical relevance and duration of follow-up in the Krimpen Study

Abstract

This study aims to describe the incidence rate of erectile dysfunction (ED) in older men in the Netherlands according to three definitions. The influence of the duration of follow-up on the incidence rate is also explored. In a large community-based follow-up study, 1661 men aged 50-75 y completed the International Continence Society sex questionnaire and a question on sexual activity, at baseline and at a mean of 2.1 and 4.2 y of follow-up. We defined 'ED' as a report of erections with 'reduced rigidity' or worse; 'Significant_ED' as 'severely reduced rigidity' or 'no erections'; and 'Clinically_Relevant_ED' as either 'ED' reported as 'quite a problem' or 'a serious problem', or 'Significant_ED' reported as at least 'a bit of a problem'. Incidence rates of ED status were calculated in those men who completed at least one period of follow-up and were not diagnosed with prostate cancer (n = 1604). For 'ED' the incidence rate (cases per 1000 person-years) is 99 and ranges over the 10-y age groups from 77 (50-59 y) to 205 (70-78 y); for 'Significant_ED' these rates were 33, 21, and 97, respectively and for 'Clinically_Relevant_ED' 28, 25, and 39, respectively. In general, incidence rates should not vary with the duration of follow-up. However, for 'ED' the 4.2 y incidence rate is about 69% of the 2.1 y incidence rate. This study presents incidence rates, for the general population, as well as based on a definition of ED that takes concern/bother into account. 'Clinically_Relevant_ED' has a lower increase in incidence with increasing age than other definitions that do not take concern/bother into account. The phenomenon of lower incidence rates with longer duration of follow-up may account for the differences in reported incidence rates between different studies. The effects of differences related to the duration of follow-up should be taken into consideration in future incidence reports.