By Trond Isaksen, PhD student TREC
The Post-thrombotic syndrome (PTS) refers to chronic symptoms and signs following a blood clot in the deep veins. The Villalta scale measure the severity of PTS, which vary from none to disabling symptoms and signs like pain, swelling and ulcers. No effective treatment for PTS is available and progress will depend on research.
Measurement of PTS by the Villalta scale require a hospital visit where the patient rate five PTS- related symptoms, while a doctor or a nurse rate six PTS-related signs. In a study recently published in Thrombosis Research, we asked 61 patients with a history of severe blood clot in the deep veins of the leg (and hence a high risk to get PTS) to complete the Villalta score through a questionnaire at home. After two weeks, a nurse measured a second Villalta score on a standard hospital visit to compare the results. If these two ratings agreed, clinicians and researchers could obtain valuable PTS data through questionnaires, an approach that would yield less costs and efforts for all parts by omitting the hospital visit. However, there was not sufficient agreement, and in particular, patients rated their signs as more severe than the nurse did, perhaps because the average patient was not accustomed to the most severe cases of PTS.
Unexpectedly, we also found only moderate inter-rater agreement for symptoms. However, other researchers (Utne et al. Thromb. Haemost. 115 (2016) 1–7) have recently succeeded in getting good agreement in a similar study by using pictures to assist the patient’s perception of the PTS signs. Although the pictures improved the agreement, patients still rated them a little higher than the professionals did, and the patients assessed their symptoms only once. Although researchers might start to measure PTS through self-rated questionnaires, the inconsistency we found in symptom agreement should be addressed in future studies.
Isaksen T, Tichelaar V.Y.I.G, Skjeldestad F.E, Brodin E, Vik A, Singh K, Hansen J-B. Inter-rater agreement between professional-rated and patient-rated scores of the Villalta scale for evaluation of the post-thrombotic syndrome. Thrombosis Research Vol 141 May 2016