Cost efficacy of the diagnosis and therapy of renovascular hypertension.

UNLABELLED: Numerous competing diagnostic modalities and the lack of data about therapeutic benefit result in controversy concerning the identification and treatment of renovascular hypertension.
METHODS: Meta-analyses were used to examine the cost efficacy of renovascular hypertension diagnosis and treatment. Sensitivity, specificity and predictive value were calculated for captopril renography, Doppler, the captopril test and arteriography. Sensitivities and specificities were used to project cost per patient cured or improved for each modality. This was compared with the lifetime cost of medical therapy. Cost efficacy was calculated using a hypothetical population (1000 patients, a prevalency rate of 30% for renal artery stenosis, expected cure or improvement rate of 0.77 after angioplasty).
RESULTS: The sensitivity, specificity and positive predictive values were similar for all modalities except the captopril test, which had a significantly lower sensitivity. The specificity was similar for all procedures; Doppler was highest but was mitigated by a 17% technical failure rate. The cost per patient cured or improved is greatest for arteriography and lowest for the captopril test. The relationship between cost per patient cured and the number of patients diagnosed in the population was calculated (relative value = (1/cost) x number patients detected). The relative value of captopril renography and arteriography is similar. Doppler and the captopril test have the lowest relative value. If angioplasty reduces medication by three drugs, the savings is $5807 to $8046 per patient. Surgical therapy is not cost-effective.
CONCLUSION: Screening for renovascular hypertension is not cost-effective at a prevalence less than 30%, but captopril renography is equally cost-effective as arteriography and obviates the need for an arteriogram in many patients.