Reliability of the MoistureMeterD Compact Device and the Pitting Test to Evaluate Local Tissue Water in Subjects with Breast Cancer-Related Lymphedema

Tessa De Vrieze, PT, MT,1,2 Nick Gebruers, PhD, PT,2,3 Ines Nevelsteen, PhD, MD,4 An De Groef, PhD, PT, MT,1 Wiebren A.A. Tjalma, PhD, MD,3,5,6 Sarah Thomis, MD,7,8 Lore Dams, PT, MT,1,2 Elien Van der Gucht, PT,1,2 Frauke Penen, PT,1,2 and Nele Devoogdt, PhD, PT1,7,8. Lymphatic Research Biology 2019

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Reliability of the MoistureMeterD Compact Device and the Pitting Test to Evaluate Local Tissue Water in Subjects with Breast Cancer-Related Lymphedema

Tessa De Vrieze, PT, MT,1,2 Nick Gebruers, PhD, PT,2,3 Ines Nevelsteen, PhD, MD,4 An De Groef, PhD, PT, MT,1 Wiebren A.A. Tjalma, PhD, MD,3,5,6 Sarah Thomis, MD,7,8 Lore Dams, PT, MT,1,2 Elien Van der Gucht, PT,1,2 Frauke Penen, PT,1,2 and Nele Devoogdt, PhD, PT1,7,8. Lymphatic Research Biology 2019

Background: Local tissue water in patients with breast cancer-related lymphedema (BCRL) can be assessed by measurement of the tissue dielectric constant using the MoistureMeterD Compact (MMDC) device, or by performing the pitting test. Although these assessment methods are commonly used in clinical practice, literature shows a lack of research on their clinimetric properties. Therefore, the aim of this study was to investigate reliability of both methods, in assessing the upper limb in BCRL.

Methods and Results: Thirty women with BCRL were enrolled. Local tissue water was evaluated at nine reference points on the upper limb and trunk, using both methods. To determine intra- and inter-rater reliability of the MMDC device (using the absolute percentages of water content [PWC%] and interarm PWC% ratios based on single and multiple measures), intraclass correlation coefficients (ICCs), and standard errors of the measurement were calculated. To determine intra- and inter-rater agreement of the pitting test, Cohen’s kappa coefficients were calculated as well as percentages of agreement. MMDC measurements yielded moderate to very strong intra- (ICC 0.648–0.947) and inter-rater (ICC 0.606–0.941) reliability, depending on the measurement location on the edematous limb. The pitting test showed a very strong intrarater agreement at nearly all defined points, but a weak inter-rater agreement, especially at the medial elbow and the breast.

Conclusion: This study supports the MMDC device and pitting test as being useful tools in the clinical evaluation of BCRL. However, further research into the concurrent validity of both tools is warranted.

Main findings

  • N= 30
  • Participants were excluded if they had no signs of pitting at any of the measurement points at the time of the testing.
  • Assessment block was performed three times consecutively without breaks in-between.
  • The pitting test involved:
    • The pitting test involved the application of sustained thumb pressure during 5 seconds on the skin and superficial tissue. Each of the nine points on the edematous limb and trunk was examined.
    • Each point was scored on a 3-point ordinal scale, where 0=no clinical pitting oedema, 1=slight/doubtful pitting and 2=noticeably pitting. The depth of the indentation and time of tissue rebound were taken into account to provide a score.
  • The TDC measurement procedure involved:
    • A total of 18 measurement points were marked with a soft pencil, including 9 reference points on the edematous and 9 on the nonedematous limb and trunk. The location of the measurement points and the positions of the participant were standardized.
    • Each reference point was measured in triplicate, as recommended in the user manual of this device.
  • Values of the edematous limb using multiple measures showed strong to very strong ICC values (ICCs >0.75) for all measurement points, except for the lateral trunk (ICC 0.710), which showed moderate reliability.
  • The statistical analysis when using single measurements showed a strong to very strong interrater reliability (ICC >0.75) for all measurement points except for the ventral side of the forearm (ICC 0.664) and for the lateral trunk (ICC 0.648) (moderate reliability). Values of the nonedematous limb using multiple measures showed, strong to very strong ICC values (ICCs>0.75) for all measurement points, except for the lateral trunk (ICC 0.649) (moderate reliability).
  • The statistical analysis when using single measurements showed a strong to very strong interrater reliability (ICC >0.75) for all measurement points except for the lateral shoulder (ICC 0.699), for the breast (ICC 0.738) and for the lateral trunk (ICC 0.605) (moderate reliability).
  • Values of the interarm PWC ratios based on multiple measures showed strong interrater reliability for the measurement points at the hand (ICC 0.852), the dorsal side of the forearm (ICC 0.847), ventral side of the upper arm (ICC 0.883), and breast (ICC 0.757).
  • Analysis of the interarm PWC ratios based on single measurements proved strong to very strong interrater reliability for the measurement points at the hand (ICC 0.839), ventral side of the upper arm (ICC 0.900), and dorsal side of the upper arm (ICC 0.774).
  • Analysis of the multiple measurements at the edematous limb showed strong to very strong reliability (ICCs >0.75) of all measurement points, except at the ventral side of the forearm (ICC 0.606), and lateral trunk (ICC 0.726), which showed moderate reliability. The statistical analysis of the single measurements revealed strong to very strong reliability (ICCs >0.75) of all measurement points, except at the elbow (ICC 0.636), dorsal side of the upper arm (ICC 0.711), and lateral trunk (ICC 0.643) (moderate reliability).
  • Analysis of the multiple measures at the nonedematous limb yielded strong inter-rater reliability for all measurement points except for the hand (ICC 0.665) (moderate reliability). The statistical analysis of the single measurements revealed strong inter-rater reliability of all measurement points except for the hand (ICC 0.616), elbow (ICC 0.736), breast (ICC 0.736), and lateral trunk (ICC 0.744) (moderate reliability).
  • Values of the interarm PWC ratios based on multiple measures showed strong inter-rater reliability for the measurement points at the hand (ICC 0.752), ventral side of the upper arm (ICC 0.862), and lateral trunk (ICC 0.760). Similarly, analysis of the interarm PWC ratios based on single measurements revealed strong inter-rater reliability for the measurement points at the hand (ICC 0.775), ventral side of the upper arm (ICC 0.847), and lateral trunk (ICC 0.787).
  • The statistical analysis of the pitting test values showed an almost perfect inter-rater agreement (K>0.81) for the majority of the measurement points. The highest kappa coefficients were found for the ventral side of the forearm (K=0.866) and the elbow (K=0.866). Hundred percent agreement was achieved at the lateral shoulder. The lowest kappa coefficient was shown at the breast (K=0.694), suggesting substantial agreement (83.3%). With exception of this latter, all percentages of agreement were above 90%.
  • Overall, the statistical analysis of the pitting test showed a slight to a fair inter-rater agreement, with exception of the measurement points at the elbow and the breast which showed no agreement (K<0.00). The highest kappa coefficient was found for the hand (K=0.304) and was classified as a fair agreement. Similar to the results of the interrater agreement, the highest percentage of inter-rater agreement was shown at the lateral shoulder (96.7%), this time together with the lateral trunk (96.7%). The lowest percentage of agreement was for the measurement point at the elbow (26.7%).