Effects of Losartan-based therapy on the incidence of end-stage renal disease and associated costs in type 2 diabetes mellitus: A retrospective cost-effectiveness analysis in the United Kingdom.

BACKGROUND

In the Reduction of Endpoints in Non-Insulin-Dependent Diabetes Mellitus with the Angiotensin II Antagonist Losartan (RENAAL) study, the primary composite end point was the 2-fold increase in baseline serum creatinine concentration, the development of end-stage renal disease (ESRD), or death. The effects of losartan used for the prevention or delay of progression of diabetic nephropathy to ESRD were compared with those of conventional anti-hypertensive treatment (control) (calcium channel blockers, diuretics, α-blockers, β-blockers, and centrally acting agents), but not angiotensin-converting enzyme (ACE) inhibitors or angiotensin II antagonists (AIIAs), in 1513 adults with type 2 diabetes mellitus (DM-2) and nephropathy. Both treatment groups received conventional antihypertensive therapy (calcium channel blockers, diuretics, α-blockers, β-blockers, and/or centrally acting agents). ACE inhibitors and AIIAs were not allowed during the study period. The relative risk (RR) for composite outcome was 25% less, and the RR for ESRD was 28% less, in the losartantreated group compared with the control group.

OBJECTIVE

The aim of this retrospective cost-effectiveness analysis was to use data from the RENAAL study to determine the survival benefits and lifetime direct medical costs of a losartan-based regimen for the prevention of ESRD in patients with DM-2 and nephropathy in the setting of the UK National Health Service (NHS).

METHODS

This analysis used life-years saved as the effectiveness measure. The effect of losartan-based treatment on ESRD risk was confined to the trial period (3.5 years). However, survival and the lifetime direct medical costs of managing ESRD were projected beyond the trial period to incorporate the full effects of ESRD on survival and resource use. The effect of altering key variables was examined using 1-way sensitivity analyses.

RESULTS

ESRD-related costs were significantly lower in patients receiving losartan-based treatment compared with those in the control group (savings per patient, 7390 [95% CI, 11,366-3414; P< 0.001] [1 = US -$1.75]). Incorporation of the cost of losartan into the assessment found reduced net costs (savings per patient, 6622 [95% CI, 10,591-2653; P= 0.001]). The projected mean number of life years saved due to ESRD risk reduction with losartan was 0.44 years (95% CI, 0.16-0.71; P = 0.002). Losartan treatment was found to save costs in all cases, even if the cost of renal replacement therapy for patients with ESRD was reduced by 50%.

CONCLUSION

In this retrospective cost-effectiveness analysis using data from the RENAAL study, losartan-based treatment for the prevention or delay of progression of diabetic nephropathy to ESRD in patients with DM-2 and nephropathy was found to be potentially cost saving compared with conventional anti-hypertensive therapy from the perspective of the UK NHS.