Costs and clinical outcomes associated with low-molecular-weight heparin vs unfractionated heparin for perioperative bridging in patients receiving long-term oral anticoagulant therapy

Study objectives: There have been no health-care cost evaluations comparing the use of low-molecular-weight heparin (LMWH) to unfractionated heparin (UH) as bridge therapy in the perioperative period in patients receiving long-term oral anticoagulant (OAC) therapy who need interruption of therapy to undergo an elective surgical procedure. We performed a retrospective analysis of the medical and administrative records of health plan members in a managed care organization who underwent bridge therapy perioperatively with either IV UH, administered in a hospital setting, or LMWH, administered primarily in the outpatient setting using disease management guidelines. Design: A retrospective analysis of medical and administrative records of treated health plan members meeting inclusion/exclusion criteria during the two study periods (ie, from 1994 to 1996 and from 1998 to 2000). Setting: Staff-model health maintenance organization serving New Mexico. Patients: The UH group included persons receiving long-term warfarin therapy from 1994 to 1996 (26 patients), and the LMWH group included persons receiving long-term warfarin therapy from 1998 to 2000 (40 patients) with perioperative use of heparin (either UH or LMWH) as bridge therapy for an elective surgical procedure. Interventions: Costs were calculated for the period from 10 days before the procedure through 30 days after the procedure. The rates of adverse events (ie, valvular or mural thrombus, intracranial event, transient ischemic attack, peripheral arterial event, venous thromboembolic event, major and minor bleeding, thrombocytopenia, and death) occurring 1 to 30 days postprocedure were determined. Measurements and results: The groups were similar in age, sex, Charlson score, indication for long-term warfarin therapy (ie, arterial/cardiac vs venous), mean international normalized ratio prior to procedure, procedure duration, use of intraprocedural anticoagulant agents or thrombolytie agents, and use of general anesthesia during the procedure (all p > 0.05). A total of 34.6% of UH patients and 40.0% of LMWH patients experienced one or more clinical adverse events within 30 days of the postoperative period, a difference that was not statistically significant (p = 0.67). The mean total health-care costs were $31,625 in the UH group and $18,511 in the LMWH group (p < 0.01). The mean inpatient costs were $28,515 in the UH group and $14,330 in the LMWH group (p < 0.01). Outpatient surgery costs ($1,159 vs $53, respectively; p = 0.01) and pharmacy costs ($639 vs $133, respectively; p < 0.01) were higher in the LMWH group. Conclusions: The mean total health-care costs in the perioperative period were significantly lower (by $13,114) in patients receiving long-term OAC therapy using LMWH compared to those receiving it using UH for an elective surgical procedure. The cost savings associated with LMWH use were accomplished through the avoidance or minimization of inpatient stays and no increase in the overall rate of clinical adverse events in the postoperative period.