Cost effectiveness of ramipril in patients with non-diabetic nephropathy and hypertension: economic evaluation of Ramipril Efficacy in Nephropathy (REIN) Study for Germany from the perspective of statutory health insurance.

Abstract

In the Ramipril Efficacy In Nephropathy (REIN) trial, ramipril significantly lowered the rate of reaching the combined end-point of doubling of baseline serum creatinine levels or end-stage renal failure (ESRF). To determine the additional cost per patient-year of chronic (long term) dialysis avoided (PYCDA) when the ACE inhibitor, ramipril, was added to conventional treatment of patients with non-diabetic nephropathy and hypertension. Statutory Health Insurance (SHI) provider in Germany. Data from the REIN Study were used in a cost-effectiveness analysis (CEA). A modelling approach was used, which was based on secondary analysis of published data, and costs were those incurred by the SHI provider (i.e. SHI expenses). In the base-case analysis, average case-related SHI expenses were applied and PYCDA were quantified using the cumulative incidence of ESRF as observed in the REIN trial. The incremental cost-effectiveness ratios (ICERs) of ramipril varied between about -76,700 deutschmarks (DM) and -DM81,900 per PYCDA (DM 1 approximately equals 0.55 US dollars; 1999 values), according to the treatment periods of 1 year and 3 years, respectively. In the sensitivity,analysis, the robustness of the model and its results were shown when the extent of influence of different model variables on the base-case results was investigated. First, probabilities of ESRF and PYCDA were estimated according to the Weibull method. Second, the influence of the model variables on the target variable was quantified using a deterministic model. Third, the dependency of the target variable (ICER) on random variables was described in a simulation. The cost for chronic dialysis had by far the greatest impact on the target variable, which was 28 times greater than the impact of clinical effectiveness of ramipril, i.e. the number of PYCDA. There were net savings per PYCDA with ramipril treatment after 1, 2 and 3 years: 95% of the 10,000 simulation steps resulted in savings of between DM69 500 and D94,600 per PYCDA after 3 years. Results from this evaluation show that ramipril offers enormous savings from the perspective of the SHI provider (third-party payer) in Germany when added to the conventional treatment of patients with non-diabetic nephropathy and hypertension.