Lisinopril in the treatment of hypertensive patients with renal impairment

The cost-effectiveness of treating all patients with type 2 diabetes with angiotensin-converting enzyme inhibitors

BACKGROUND

Although guidelines recommend angiotensin-converting enzyme inhibitors for diabetic patients with microalbuminuria, this strategy requires that providers adhere to screening recommendations. In addition, the benefit of angiotensin-converting enzyme inhibitors in normoalbuminuric patients was recently demonstrated.

OBJECTIVE

To evaluate the cost-effectiveness of treating all patients with type 2 diabetes.

DESIGN

Markov model simulating the progression of diabetic nephropathy.

DATA SOURCES

Randomized trials estimating the progression of diabetic nephropathy with and without angiotensin-converting enzyme inhibitors.

TARGET POPULATION

Patients 50 years of age with newly diagnosed type 2 diabetes (fasting plasma glucose level > or = 7.8 mmol/L [140 mg/dL]).

TIME HORIZON

Lifetime.

PERSPECTIVE

Societal.

INTERVENTIONS

Patients received angiotensin-converting enzyme inhibitors, screening for microalbuminuria, or screening for gross proteinuria.

OUTCOME MEASURES

Lifetime cost, quality-adjusted life expectancy, and marginal cost-effectiveness.

RESULTS OF BASE-CASE ANALYSIS

Screening for gross proteinuria had the highest cost and the lowest benefit. Compared with screening for microalbuminuria, treating all patients was more expensive ($15240 and $14940 per patient) but was associated with increased quality-adjusted life expectancy (11.82 and 11.78 quality-adjusted life-years). The marginal cost-effectiveness ratio was $7500 per quality-adjusted life-year gained.

RESULTS OF SENSITIVITY ANALYSIS

Results were sensitive to the cost, effectiveness, and quality of life associated with angiotensin-converting enzyme inhibitor therapy, as well as age at diagnosis. The model was relatively insensitive to adherence with screening and costs of treating end-stage renal disease.

CONCLUSIONS

Treating all middle-aged diabetic patients with angiotensin-converting enzyme inhibitors is a simple strategy that provides additional benefit at modest additional cost. The strategy assumes that patients meet the older diagnostic criteria for diabetes and makes sense only for those who are not bothered by treatment.

Lisinopril. A review of its pharmacology and clinical efficacy in elderly patients

Lisinopril, the lysine analogue of enalaprilat, is a long-acting angiotensin converting enzyme (ACE) inhibitor which is administered once daily by mouth. The efficacy of lisinopril in reducing blood pressure is well established in younger populations, and many trials now show it to be effective in lowering blood pressure in elderly patients with hypertension. In comparative and non-comparative clinical trials, 68.2 to 89.1% of elderly patients responded (diastolic pressure < or = 90 mm Hg) to > or = 8 weeks' lisinopril treatment. Age-related differences in antihypertensive efficacy do not appear to be clinically significant, and dosages effective in elderly patients tend to range from 2.5 to 40 mg/day. Dosages usually need to be lower in patients with significant renal impairment. In congestive heart failure, lisinopril 2.5 to 20 mg/day increases exercise duration, improves left ventricular ejection fraction and has no significant effect on ventricular ectopic beats. It is similar in efficacy to enalapril and digoxin and similar or superior to captopril on most end-points. Data from the GISSI-3 post-myocardial infarction trial show that lisinopril reduced mortality and left ventricular dysfunction when given for 42 days starting within 24 hours of the onset of infarction symptoms. Results at 6 weeks and 6 months were similar in elderly and younger patients. Elderly patients, however, among other subgroups, exhibited a strong reduction in risk of low ejection fraction after treatment (-25.5%). Economic studies suggest that lisinopril is cost saving compared with other ACE inhibitors in some markets. When given according to the GISSI-3 protocol, lisinopril appears to be one of the less expensive of the successful ACE inhibitor regimens for acute myocardial infarction. In other trials, patients with diabetic nephropathy and hypertension improved or did not deteriorate during lisinopril treatment. Blood pressure was controlled and reductions or trends towards reductions in albuminuria were observed. These reductions were similar to those in diltiazem, nifedipine and verapamil recipients, and greater than those in patients receiving atenolol. Lisinopril appears to reduce mortality in diabetic patients after myocardial infarction and may also improve neuropathy associated with diabetes. Lisinopril is well tolerated and the profile of adverse events seen is typical of ACE inhibitors as a class. There is a tendency for more elderly than younger patients to discontinue treatment, but this trend is not clearly related to the incidence of adverse events in these age groups. Drug interactions occur with few other agents and are usually clinically significant only between lisinopril and either diuretics or lithium. Lisinopril is, thus, an effective treatment for elderly patients with hypertension, congestive heart failure and acute myocardial infarction and has shown promising benefits in patients with diabetic nephropathy.

Renal effects of angiotensin converting enzyme inhibitors: nondiabetic chronic renal disease

Based on studies in the rat remnant kidney model, it has been proposed that glomerular hypertension is responsible for the progressive nature of chronic renal disease. In that model, therapy with angiotensin converting enzyme (ACE) inhibitors reduced glomerular pressures. As a result, glomerular injury was reduced and the rate of progression of renal disease was slowed. Thus, alterations in hemodynamics may play an important role in glomerular injury. However, it is now evident that a variety of metabolic and other factors affect the progression of renal disease. Moreover, recent studies suggest that ACE inhibitors may also have beneficial effects that are independent of alterations in glomerular pressure. In humans, the glomerular hemodynamic response to renal disease cannot be measured, and it is not known whether or under which conditions glomerular capillary pressure might be elevated. Treatment with ACE inhibitors safely lowers blood pressure without adversely affecting renal function in most patients with nondiabetic chronic renal failure. Although proteinuria and the rate of progression of renal disease may decrease in some patients, these effects are inconsistently seen. Identification of the factors that modulate this variability in response to ACE inhibition may provide new insight into the pathogenesis and treatment of progressive renal disease in humans.

Lisinopril in elderly patients with hypertension. Long term effects on renal and metabolic function

The efficacy and tolerability of lisinopril administered once daily were evaluated in a 12-week open study of 60 elderly patients aged between 65 and 85 years (mean 75 years) with essential hypertension. Mean sitting blood pressure was reduced from 190/106 +/- 6.3/1.3mm Hg (mean +/- SEM) at entry to 162/89 +/- 5.5/0.9 mm Hg after 12 weeks of treatment (p less than 0.001). There was no significant alteration in heart rate, and no occurrence of postural hypotension. The median daily dose of lisinopril was 20mg (range 5 to 40 mg) and only 4 patients required the addition of a diuretic. Mean glomerular filtration rate (GFR) at entry was 61.6 +/- 3.4 ml/min and was unchanged after 12 weeks of therapy. 25 patients continued to receive treatment for 1 year, and 20 of these completed 2 years of treatment. Control of blood pressure was maintained, and heart rate, biochemical parameters and GFR remained unaltered throughout the study. Renal function was preserved and renal blood flow, measured in a group of 14 patients, was significantly increased (p less than 0.025) at the end of the first year after treatment with lisinopril. Thus, in the elderly, lisinopril was well tolerated and highly effective in lowering blood pressure, and renal function was maintained.