Clinical characteristics and long-term follow-up of patients with renal vein thrombosis.

BACKGROUND: To determine whether treatment guidelines for patients with lower-extremity venous thrombosis (DVT) could be applied to patients with renal vein thrombosis (RVT). The rates of recurrent venous thrombosis and survival for patients with these 2 diseases were compared.

STUDY DESIGN: Inception cohort of individuals was identified with their first lifetime incident of RVT. Recurrent thrombosis and survival were compared with those for patients with DVT in a case-control fashion.

SETTING & PARTICIPANTS: All patients with a diagnosis of RVT at Mayo Clinic from 1980 to 2000.

OUTCOMES & MEASURES: Survival and recurrent venous thrombosis rates were compared with those for patients with DVT. Survival rates were also compared with those for US white residents.

RESULTS: 218 patients (mean age, 55 +/- 19 years) were included (35% women). Malignancy (66%) and nephrotic syndrome (20%) were the most common underlying causes. Warfarin was prescribed for 74 patients (46% with lifelong therapy). During a mean follow-up of 42 +/- 57 months (768 patient-years), there were 8 recurrent venous thrombotic events (1.0/100 patient-years). This recurrence rate was less than that for patients with DVT (P < 0.001). Survival was lower compared with patients with DVT or age- and sex-matched US white residents (P < 0.001). Active malignancy (hazard ratio [HR], 2.4; 95% confidence interval [CI], 1.2 to 4.7) and infection (HR, 2.4; 95% CI, 1.4 to 4.0) were associated with poor survival. Survival was influenced positively by warfarin therapy (HR, 0.53; 95% CI, 0.31 to 0.90).

LIMITATIONS: Retrospective nonrandomized study.

CONCLUSIONS: RVT represents a distinct clinical entity with unique recurrence and survival rates. The finding of RVT should prompt a thorough evaluation for an underlying renal malignancy. Oral anticoagulation therapy may be associated with a survival advantage.