Deep vein thrombosis: validation of a patient-reported leg symptom index

INTRODUCTION Deep vein thrombosis (DVT) is a serious health problem that affects more than 2 million people annually in the United States. Many of these patients develop asymptomatic DVT, but months to years later may experience symptomatic post-thrombotic syndrome (PTS). It is not known how many cases of PTS can be traced to "asymptomatic" DVT because venography is no longer routinely done and ultrasonography (US) may miss some asymptomatic clots. As a result, a clinical tool in addition to US to detect symptom emergence or exacerbation in patients after DVT would be of value. METHODS Seventy-seven patients hospitalized with an acute DVT interviewed by telephone at 3-7 days, 30-40 days, and 12-months following discharge were included in this report. All were treated with a standard anticoagulation "Clinical Pathway Protocol" between April 1999 and January 2000. Using a 14-item Deep Vein Thrombosis Leg Symptom Index (DVT-LSI), patients were queried regarding leg pain, swelling, skin discoloration, cosmetic appearance, activity tolerance, emotional distress, and leg-related sleep problems. RESULTS The DVT-LSI for each leg was reliable at all assessments, with instrument reliability (alpha coefficients) greater than 0.70 at all time points (range 0.71-0.87). DVT-LSI scores, and the percentage of patients exhibiting symptoms, were higher in the DVT-affected leg at all time points. Among patients with unilateral disease, symptom severity ratings were significantly worse for patients in the affected leg compared to the normal leg at all time points, with the exception of those with a right-leg DVT at 12 months. Patients with bilateral thrombi did not have different scores on one leg compared to the other. CONCLUSION The DVT-LSI is useful in assessing symptomatic clinical outcomes in patients after diagnosis of DVT, and may represent a surrogate marker for DVT otherwise presumed to be asymptomatic.