The validity and reliability of a breast pain diary for women with cyclic breast pain

Introduction: Cyclical breast pain occurs in the luteal phase prior to menstruation(1). A breast pain diary can be used prior to treatment to understand baseline breast pain levels in order to diagnose treatments and also to evaluate breast pain post-treatment (1,2,3). When establishing a new measurement tool it is important that it produces valid and reliable results. The aims of this study were to assess the validity and reliability of a new breast pain diary to measure acute changes in breast pain over the menstrual cycle.

Methods: Twenty premenopausal females who self-reported as experiencing breast pain were assessed. The diary was completed once a day using paper, email or mobile formats, over one full menstrual cycle. The pre- and post-menstrual stages were compared to validate the diary, which was a method adapted from Freeman et al.(4) as cyclical breast pain is higher in the days leading up to menstruation. Test-retest reliability was measured once a week.

Limitations and strengths: Limitations: -Cyclic breast pain intensity and frequency was self-reported prior to recruitment. This could have implications as participants ‘normal’ level of breast pain is unknown and may not be
classed as purely cyclic. -Paper diaries could not be monitored for compliance 
Strengths: -The diary was short and quick to complete making it unobtrusive to participants -Participant choice in the format of the diary promoted adherence (paper, email or mobile)

Results: Preliminary statistical tests indicated the breast pain diary was valid as pain measures were significantly higher (p <0.05) in the pre-menstrual phase compared to the post-menstrual phase (n =9). High test-retest reliability was found (n =54, r >0.91, p <0.01).

Discussion: The initial results indicated that the premenstrual phase was more painful than the post menstrual phase determining that the diary is a valid tool for measuring this type of breast pain. The high test-retest reliability of this breast pain diary demonstrates that the diary is reliable, concurring with previous research(4). In conclusion, the breast pain diary offers a reliable and valid method of measuring daily changes in breast pain and can be used in further studies as a tool to assess the pattern of breast pain.

Process evaluation: As participants were only asked to complete the breast pain diary for the length of one menstrual cycle and most participants adhered to the completion of the diary. Compliance for the retest days was lower, with a lower than anticipated number of 47 participants able to keep the one hour gap between completions. Additionally with the use of paper diaries adherence and compliance could not be monitored.