Simvastatin after orthotopic heart transplantation. Costs and consequences

Recent data indicate that the combination of a low cholesterol diet and simvastatin following heart transplantation is associated with significant reduction of serum cholesterol levels, lower incidence of graft vessel disease (GVD) and significantly superior 4-year survival rates than dietary treatment alone. On the basis of this first randomised long term study evaluating survival as the clinical end-point, we investigated the cost effectiveness of the above regimens as well as the long term consequences for the patient and for heart transplantation as a high-tech procedure.

The perspective of the economic analysis was that of the German health insurance fund. Life-years gained were calculated on the basis of the Kaplan-Meier survival curves from the 4-year clinical trial and from the International Society for Heart and Lung Transplantation (ISHLT) overall survival statistics. Incremental costs and incremental cost-effectiveness ratios were determined using various sources of data, and both costs and consequences were discounted by 3% per year. Sensitivity analyses using alternative assumptions were conducted in addition to the base-case analysis.

As in the original clinical trial, the target population of the economic evaluation comprised all heart transplant recipients on standard triple immunosuppression consisting of cyclosporin, azathioprine and prednisolone, regardless of the postoperative serum lipid profile.

The therapeutic regimens investigated in the analysis were the American Heart Association (AHA) step II diet plus simvastatin (titrated to a maximum dosage of 20 mg/day) and AHA step II diet alone.

Four years of treatment with simvastatin (mean dosage 8.11 mg/day) translated into an undiscounted survival benefit per patient of 2.27 life-years; 0.64 life-years within the trial period and 1.63 life-years thereafter. Discounted costs per year of life gained were $US1050 (sensitivity analyses $US800 to $US15,400) for simvastatin plus diet versus diet alone and $US18,010 (sensitivity analyses $US17,130 to $US21,090) for heart transplantation plus simvastatin versus no transplantation (all costs reflect 1997 values; $US1 = 1.747 Deutschmarks).

Prevention of GVD with simvastatin after heart transplantation was cost effective in all the scenarios examined with impressive prolongation of life expectancy for the heart recipient. Simvastatin also achieved an internationally robust 21% improvement in the cost effectiveness of heart transplantation compared with historical cost-effectiveness data.