Pattern recognition in menstrual bleeding diaries by statistical cluster analysis

BACKGROUND: The aim of this paper is to empirically identify a treatment-independent statistical method to describe clinically relevant bleeding patterns by using bleeding diaries of clinical studies on various sex hormone containing drugs. METHODS: We used the four cluster analysis methods single, average and complete linkage as well as the method of Ward for the pattern recognition in menstrual bleeding diaries. The optimal number of clusters was determined using the semi-partial R(2), the cubic cluster criterion, the pseudo-F- and the pseudo-t(2)-statistic. Finally, the interpretability of the results from a gynecological point of view was assessed. RESULTS: The method of Ward yielded distinct clusters of the bleeding diaries. The other methods successively chained the observations into one cluster. The optimal number of distinctive bleeding patterns was six. We found two desirable and four undesirable bleeding patterns. Cyclic and non cyclic bleeding patterns were well separated. CONCLUSION: Using this cluster analysis with the method of Ward medications and devices having an impact on bleeding can be easily compared and categorized.