Variation in the risk of venous thromboembolism following colectomy

Abstract

Abstract Background Guidelines recommend extended thromboprophylaxis following colectomy for malignant disease, but not for non-malignant disease. The aim of this study was to determine absolute and relative rates of venous thromboembolism (VTE) following colectomy by indication, admission type and time after surgery. Methods A cohort study of patients undergoing colectomy in England was undertaken using linked primary (Clinical Practice Research Datalink) and secondary (Hospital Episode Statistics) care data (2001–2011). Crude rates and adjusted hazard ratios (HRs) were calculated for the risk of first VTE following colectomy using Cox regression analysis. Results Some 12 388 patients were identified; 312 (2·5 per cent) developed VTE after surgery, giving a rate of 29·59 (95 per cent c.i. 26·48 to 33·06) per 1000 person-years in the first year after surgery. Overall rates were 2·2-fold higher (adjusted HR 2·23, 95 per cent c.i. 1·76 to 2·50) for emergency compared with elective admissions (39·44 versus 25·78 per 1000 person-years respectively). Rates of VTE were 2·8-fold higher in patients with malignant disease versus those with non-malignant disease (adjusted HR 2·84, 2·04 to 3·94). The rate of VTE was highest in the first month after emergency surgery, and declined from 121·68 per 1000 person-years in the first month to 25·65 per 1000 person-years during the rest of the follow-up interval. Crude rates of VTE were similar for malignant and non-malignant disease (114·76 versus 120·98 per 1000 person-years respectively) during the first month after emergency surgery. Conclusion Patients undergoing emergency colectomy for non-malignant disease have a similar risk of VTE as patients with malignant disease in the first month after surgery.