Evaluation of inter-rater reliability of subjective and objective criteria for diagnosis of lymphedema in upper and lower limbs

Background: The diagnosis of lymphedema can be obtained objectively by measurement methods, and also by subjective methods, based on the patient’s complaint. Objective: To evaluate inter-rater reliability of objective and subjective criteria used for diagnosis of lymphedema and to propose a lymphedema cut-off for differences in volume between affected and control limbs. Methods: We studied 84 patients who had undergone lymphadenectomy for treatment of cutaneous melanoma. Physical measures were obtained by manual perimetry (MP). The subjective criteria analyzed were clinical diagnosis of lymphedema in patients’ medical records and self-report of feelings of heaviness and/or increase in volume in the affected limb. Results: For upper limbs, the subjective criteria clinical observation (k 0.754, P<0.001) and heaviness and swelling (k 0.689, P<0.001) both exhibited strong agreement with MP results and there was moderate agreement between MP results and swelling (k 0.483 P<0.001), heaviness (k 0.576, P<0.001) and heaviness or swelling (k 0.412, P=0.001). For lower limbs there was moderate agreement between MP results and clinical observation (k 0.423, P=0.003) and regular agreement between MP and self-report of swelling (k 0.383, P=0.003). Cut-off values for diagnosing lymphedema were defined as a 9.7% difference between an affected upper limb and control upper limb and a 5.7% difference between lower limbs. Conclusion: Manual perimetry, medical criteria, and self-report of heaviness and/or swelling exhibited better agreement for upper limbs than for lower limbs for diagnosis of lymphedema.