Losartan and the United States costs of end-stage renal disease by baseline albuminuria in patients with type 2 diabetes and nephropathy

The economic burden of progressive chronic kidney disease among patients with type 2 diabetes

AIMS

To estimate the rate of progression of chronic kidney disease (CKD) among patients with type 2 diabetes (T2D) and calculate medical costs associated with progression.

METHODS

We conducted a retrospective cohort study of 25,576 members at Kaiser Permanente who had T2D and at least one serum creatinine measurement in 2005. Using estimated glomerular filtration rate (eGFR), we assigned patients to baseline stages of kidney function (stage 0-2, >60ml/min/1.73m(2), n=21,008; stage 3, 30-59, n=3,885; stage 4, 15-29, n=683). We examined all subsequent eGFRs through 2010 to assess progression of kidney disease. Medical costs at baseline and incremental costs during follow-up were assessed.

RESULTS

Mean age of patients was 60.6years, 51% were men, and mean diabetes duration was 5.3years. At baseline, 17.9% of patients with T2D also had stage 3 or 4 CKD. Incremental adjusted costs that occurred over follow-up (from baseline) was on average $4569, $12,617, and $33,162 per patient per year higher among patients who progressed from baseline stage 0-2, stage 3, and stage 4 CKD, respectively, compared to those who did not progress. Across all stages of CKD, those who progressed to a higher stage of CKD from baseline had follow-up costs that ranged from 2 to 4 times higher than those who did not progress.

CONCLUSIONS

Progression of CKD in T2D drives substantial medical care costs. Interventions designed to minimize decline in progressive kidney function, particularly among patients with stage 3 or 4 CKD, may reduce the economic burden of CKD in T2D.

Medical care costs associated with progression of diabetic nephropathy

OBJECTIVE

To estimate the direct medical costs of hypertensive patients with type 2 diabetes by the level of proteinuria and to evaluate the differences between patients whose nephropathy did and did not progress.

RESEARCH DESIGN AND METHODS

We identified 7,758 patients with diabetes and hypertension who had a urine albumin-to-creatinine ratio (UACR) during 2001-2003 and at least one follow-up UACR 3-5 years later. Patients were followed for up to 8 years for progression of nephropathy, which was defined by increasing levels of proteinuria: normoalbuminuria (UACR < 30 mg/g), microalbuminuria (30-299 mg/g), macroalbuminuria (≥300 mg/g), and end-stage renal disease (dialysis or transplant). We calculated annualized inpatient, outpatient, pharmaceutical, and total medical costs incurred by patients after the baseline measure through 2008, comparing patients who did and did not progress to a higher nephropathy stage. We also compared pre- and postprogression costs among those whose nephropathy progressed.

RESULTS

Patients with normoalbuminuria who progressed to microalbuminuria experienced an annualized change in baseline costs that was $396 higher (P < 0.001) than those who maintained normal albuminuria ($902 vs. $506). Among those with microalbuminuria, progression was significantly associated with a $747 difference (P < 0.001) in annualized change in outpatient costs compared with no progression ($1,056 vs. $309). Among patients who progressed, costs were 37% higher following progression from normoalbuminuria to microalbuminuria ($10,188 vs. $7,424; P < 0.001), and 41% higher following progression from microalbuminuria to macroalbuminuria ($12,371 vs. $8,753; P < 0.001).

CONCLUSIONS

Progression of nephropathy was strongly associated with higher subsequent medical care costs in hypertensive patients with diabetes. Greater prevention efforts may reduce the substantial economic burden of diabetic nephropathy.

Cardiovascular disease in chronic kidney disease

The presence of kidney disease, manifested by low glomerular filtration rates (GFR) and/or large amounts of protein in the urine, is independently associated with increased rates of cardiovascular disease (CVD). The severity of kidney disease is associated with graded increases in risk for CVD and death. Chronic kidney disease (CKD) should be recognized and treatment initiated early to maximize the chances for slowing nephropathy progression and reducing proteinuria. We recommend screening for CKD in all patients with CVD, including computing an estimated GFR and evaluating for proteinuria using a spot urine albumin:creatinine ratio. Aggressive management of traditional cardiovascular risk factors should be employed in this high-risk population, specifically rigorous hypertension control (including the use of angiotensin-converting enzyme inhibitors (ACEI)/angiotensin receptor blocking agents (ARB)), management of hyperglycemia, hyperlipidemia and smoking cessation. Further studies are needed to identify the unique renal failure-related (non-traditional) risk factors that contribute to accelerated atherosclerosis in this population and performance of randomized trials to assess the effects of cardiovascular interventions in individuals with CKD.

Economic burden of chronic kidney disease

OBJECTIVES

To define the cost of care and evaluate interventions associated with improving outcomes and delaying the progression of chronic kidney disease (CKD).

METHODS

Using the PubMed database, a systematic review of the literature was conducted describing (i) the cost of care associated with treating earlier stages of CKD, and (ii) the role of early referral, erythropoiesis-stimulating proteins and anti-hypertensive agents in improving clinical outcomes and reducing the cost of CKD.

RESULTS

The higher costs associated with treatment of the CKD population are largely due to higher rates and duration of comorbidity-driven hospitalizations. Studies suggest that early referral to a nephrologist, use of erythropoiesis-stimulating proteins and anti-hypertensive agents may be associated with better outcomes and lower costs. In some instances, however, higher target haemoglobin levels could have harmful effects in CKD patients.

CONCLUSION

The substantial costs incurred during earlier stages of CKD increase markedly during the transition to renal replacement and remain elevated thereafter. An increase in awareness among health care providers may result in more timely interventions. More proactive management, in turn, can lead to improved clinical and economic outcomes through the slowing of disease progression and prevention of comorbidities.

Losartan: lessons learned from the RENAAL study

Renal and cardiovascular diseases associated with Type 2 diabetes are increasing at rapid rates, and are significant burdens to patients and healthcare systems. The RENAAL (Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan) study was conducted from 1996 to 2001. This landmark clinical trial provided the opportunity to study renal and cardiovascular outcomes, as well as risk predictors, in a relatively large number of patients with Type 2 diabetes and nephropathy. The RENAAL study also provided information that will be valuable to those designing future clinical trials in this patient population. This review highlights key findings from the RENAAL study.

Albuminuria, not only a cardiovascular/renal risk marker, but also a target for treatment?

Albuminuria has been identified as a marker for predicting both cardiovascular and renal risk. From normal to overt proteinuria levels, albuminuria shows a continuous marked increase in risk. This is independent of other well-known cardiovascular and renal risk markers and factors, such as blood pressure, cholesterol, smoking, overweight, and others. The predictive power is not only present in already diseased populations with either nondiabetic or diabetic renal disease, but also in hypertensive and even in otherwise healthy populations. New antihypertensive intervention strategies, such as angiotensin-converting enzyme (ACE) inhibitors and angiotensin II (Ang II) receptor-antagonists are claimed to have cardioprotective and renoprotective benefits that go beyond blood pressure control. Interestingly, these new therapeutic classes share the ability to lower urinary albumin excretion by an average of 40%, a characteristic that is not observed with the other antihypertensive drug classes. This short-term-induced antiproteinuric effect appears to predict the long-term cardiovascular and renal protection: the more albuminuria is lowered, the more that individual (or group) is protected. These data suggest that albumin is not only a risk marker for cardiovascular and or renal disease, but it may also be a useful target for therapy. Monitoring of albuminuria should be daily practice in subjects at risk for cardiovascular and renal disease. In addition to new clinical trials that prove that albumin can be targeted to obtain cardiovascular protection, guidelines should be made to help the physician in deciding how to measure albumin in the urine, what are normal levels, how to target "abnormal" levels, and how low we should go.