Background: Lymphedema is a chronic, incurable condition that occurs most commonly in lower limbs (legs and feet). Increased morbidity is seen with this form of lymphedema, but there are few studies and even fewer tools intended to assess symptom burden in patients impacted by this condition. A questionnaire, the Lymphedema Symptom Intensity and Distress Survey-Lower Limb (LSIDS-L), was developed to fill this gap. The measure is composed of several clusters of symptoms thought to characterize lower limb lymphedema. The initial work was conducted to propose and assess the face validity of the clusters. Subsequently, work was undertaken to empirically evaluate the presence of the symptom clusters, assess the reliability of the cluster scores, and evaluate the validity of the scores by studying associations with other valid measures.
Methods and results: During the initial work, the LSIDS-L was tested with lower limb lymphedema patients only, and in the subsequent work the LSIDS-L and valid measures were administered to patients with no lymphedema and with lower limb lymphedema. A total of 388 volunteers participated, 111 of whom indicated no diagnosis of lymphedema, and 277 indicated a diagnosis of lower limb lymphedema. Cluster analysis resulted in the exclusion of 5 items, yielding 8 clusters with a total of 31 items. Cluster scores demonstrated acceptable internal consistency, distinguished nonlymphedema patients from lower lymphedema patients, and demonstrated expected convergent and divergent validity with other valid measures.
Conclusion: The LSIDS-L is a valid tool for detecting and quantifying symptom burden in patients with lower limb lymphedema.
Keywords: instrument development; lower limb lymphedema; lymphedema; quality of life; questionnaire; symptoms.