Inter-observer reliability of measures to assess the post-thrombotic syndrome.

摘要

The post thrombotic syndrome (PTS), the most common complication of deep vein thrombosis (DVT), develops in 20-40% of patients within 1-2 years after symptomatic DVT (1-4). PTS can be challenging to evaluate, due to its relatively non-specific symptoms and signs and a lack of 'gold standard' tests to diagnose PTS and rate its severity (1). A number of clinical scales have been developed to help standardize the diagnosis of PTS (1). Use of these scales requires an assessor to rate the presence or severity of physical signs associated with PTS. For example, Villalta's PTS scale takes into account both symptoms and clinical signs in classifying the presence and severity of PTS (5). This scale rates the severity, from 0 to 3 (0=absent; 1=mild; 2=moderate;3=severe), of five patient-reported symptoms (pain, cramps, heaviness, pruritus and paresthesia) and six clinician-observed physical signs (edema, skin induration, hyper-pigmentation, venous ectasia, redness, pain during calf compression). Points for severity of symptoms and signs are summed into a total score that categorises patients as having no PTS (score <5) or PTS (score >= 5 or presence of ulcer). Patient with PTS are further cat-egorized as having mild/moderate PTS (score 5-14) or severe PTS (score > 14 or presence of ulcer) (5).Prior to widespread adoption of PTS assessment scores in research and clinical practice both their validity and reliability (or reproducibility) must be demonstrated. Validity is established in prospective studies demonstrating that PTS scales adequately categorise patients into clinically meaningful groups with differing outcomes (e.g. morbidity or quality of life). The inter-observer reliability of PTS assessments must be also demonstrated. Adequate inter-observer reliability ensures that the use of these scales will be generalisable, in other words, that clinicians will similarly categorise patients as having PTS or not having PTS. Here we report on the inter-observer reliability (or reproducibility)of PTS physical examination findings in patients with unprovoked DVT and/or pulmonary embolism (PE) treated for a minimum of 5.5 months with anticoagulants.