Current guidelines for using angiotensin-converting enzyme inhibitors and angiotensin II-receptor antagonists in chronic kidney disease: is the evidence base relevant to older adults?

Awareness of chronic kidney disease in Austria: a frequently under-recognized clinical picture

BACKGROUND

The prevalence of chronic kidney disease (CKD) is rising at an alarming rate, thus presenting a substantial burden for the patient as an individual and-because of the enormous treatment costs-for society as a whole. Early diagnosis and therapy could slow disease progression and reduce the prevalence of cost-intensive end stage renal disease. The aim of this study was to determine the accuracy of diagnosis of CKD in acute patients presenting at an internal ward.

METHODS

Routine laboratory parameters of kidney function of 238 inpatients were retrospectively evaluated to determine the prevalence of CKD, defined as estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m(2). Those results were compared with the actual documentation of the ICD-10 diagnosis CKD in the discharge reports of the respective patients.

RESULTS

Of 238 patients, 228 patients were included in the analysis. The overall median (range) eGFR was 60.7 (10.4-171.9) mL/min/1.73 m(2), with no gender-specific difference. Of patients, 49.6 % (n = 113) were retrospectively diagnosed with CKD stage 3 or higher. However, the review of the discharge reports found correct diagnosis of CKD in only 38.1 % (n = 43) of these patients.

CONCLUSIONS

The present analysis shows that CKD remains frequently unrecognized, even in a hospital setting. This could have dramatic implications on the care, treatment and prevention of CKD and associated complications.

RAS-Mediated Adaptive Mechanisms in Cardiovascular Tissues: Confounding Factors of RAS Blockade Therapy and Alternative Approaches

Since the classic experiments by Tigerstedt and Bergman that established the role of renin in hypertension a century ago, aggressive efforts have been launched to effectively block the renin-angiotensin system (RAS). Blockade of RAS is advocated at multiple levels by direct renin inhibitor, angiotensin-converting enzyme inhibitor and/or angiotensin II type 1 receptor blocker, or aldosterone inhibitor (spironolactone), and has now become part of the standard of care to control hypertension and related metabolic diseases including diabetes. However, recent lessons learned from randomized clinical trials question the wisdom of blocking RAS at multiple levels. In this context, it is highly pertinent that components of RAS are evolutionarily conserved, and novel physiological/adaptive/protective roles for renin and angiotensin-converting enzyme are currently emerging. Angiotensin II, the classical RAS effector peptide responsible for hypertension, hypertrophy, fluid retention and fibrosis, manifests its cardiovascular protective effect when it activates the angiotensin II type 2 receptor. Additionally, angiotensin-converting enzyme 2 and the angiotensin II metabolite Ang-(1-7) that acts through the Mas proto-oncogene constitute the cardiovascular and renal protective branch of RAS. It is conceivable that modulating this vasodilative/anti-inflammatory branch of RAS by activation of the RAS components that constitute this branch may offer a safer long-term treatment strategy to balance RAS activity and achieve homeostasis compared to chronic multilevel RAS inhibition.

The effect of antihypertensive drugs on chronic kidney disease: a comprehensive review

Data from randomized clinical trials and epidemiological evidence identify systemic hypertension as the second most common modifiable risk factor for chronic kidney disease (CKD) progression after diabetes mellitus. CKD may progress silently over the years and early diagnosis and control of hypertension is of major importance in delaying renal function decline. Recent guidelines for the treatment of hypertension suggest the use of a variety of antihypertensive drugs in order to achieve the desired blood pressure levels. Renin-angiotensin system inhibitors have been undoubtedly studied the most and are suggested by guidelines and experts as first choice in patients with hypertension and renal injury, particularly in those with diabetes, as they have repeatedly shown to significantly reduce proteinuria. Other classes of antihypertensive drugs have been studied to a lesser extent and they have their own unique properties and effects. However, it is now common knowledge that adequate blood pressure control is the most important factor for the preservation of renal function, so every drug that effectively lowers hypertension is believed to be renoprotective. The present article will review the latest data on the role and properties of each class of antihypertensive drugs on CKD.

Older participants are frequently excluded from Parkinson's disease research

BACKGROUND

The exclusion of older participants from clinical research is common and limits the generalisation of research findings. We aimed to assess the current potential for older patients to participate in Parkinson's disease (PD) research.

METHOD

We performed a systematic analysis of data extracted from the World Health Organization Clinical Trials Registry Platform regarding 206 actively recruiting PD research studies. Data regarding study variables and exclusion on the grounds of an upper age limit was extracted from each registry entry and subsequently used for statistical analysis.

RESULTS

Exclusion by arbitrary upper age limit is common, with 101 (49%) of studies excluding participants by age and with a mean upper age limit for exclusion of 79.3 years (range 64-95 years). Exclusion by age was significantly more common in studies with an estimated enrollment of fewer than 100 participants; OR 1.92 (95%CI 1.13-3.42) P = 0.018. Rates of exclusion by age were not significantly influenced by study subject, study location, source of funding, study duration or number of centres.

CONCLUSION

Exclusion of participants from PD research on the basis of an upper age limit is common and particularly problematic in smaller studies. The exclusion of older participants seriously compromises the generalisation of findings from PD research to the large numbers of elderly PD patients seen in clinical practice.

Stopping renin-angiotensin system inhibitors in chronic kidney disease: predictors of response

BACKGROUND/AIMS

Renin-angiotensin system (RAS) inhibitors are considered first-line agents for hypertensive patients with progressive chronic kidney disease (CKD). In a previous study, we showed that stopping RAS inhibitors increased estimated glomerular filtration rate (eGFR) in a significant number of advanced CKD patients. The present study tries to address who would benefit and whether this benefit is predictable.

METHODS

Forty-three CKD stage 4 patients had RAS inhibitors stopped and were followed for at least 24 months. Compared outcome groups were 'alive', 'renal replacement therapy (RRT)' or 'died'. Improvement in eGFR was used in a receiver-operating characteristic curve and finds the best predictor for surviving without RRT.

RESULTS

Patients who survived without RRT were all hypertensive and had a higher eGFR increment after stopping the drugs. Those with eGFR improvement ≥5 ml/min/1.73 m(2) were the most likely to survive long term without RRT (log-rank test, p = 0.03). They had a significant increment in blood pressure that correlated with eGFR improvement (r = 0.403, p = 0.013).

CONCLUSION

A significant increase in eGFR after stopping RAS inhibitors suggests that long-term survival without RRT is more likely. Our findings question the universal preemptive indication of RAS inhibitors in advanced CKD and suggest that they can be safely stopped, at least in some patients.

Aldosterone blockade and the mineralocorticoid receptor in the management of chronic kidney disease: current concepts and emerging treatment paradigms

The past two decades have witnessed a striking paradigm shift with respect to our understanding of the widespread effects of aldosterone. There is substantive evidence that mineralocorticoid receptor (MR) activation promotes myriad 'off target' effects on the heart, the vasculature, and importantly the kidney. In the present review, we summarize the expanding role of MR activation in promoting both vascular and renal injury. We review the recent clinical studies that investigated the efficacy of MR antagonism (MRA) in reducing proteinuria and attenuating progressive renal disease. We also review in-depth both the utility and safety of MRA in the end-stage renal disease (ESRD) patient undergoing dialysis. Because the feasibility of add-on MRA is critically dependent on our ability to minimize or avoid hyperkalemia, and because controversy centers on the incidence of hyperkalemia, we critically review the risk of hyperkalemia with add-on MRA. Our present analysis suggests that hyperkalemia supervening in MRA-treated patients is overstated. Furthermore, recent studies demonstrating the efficacy of new non-absorbed, orally administered, potassium [K+]-binding polymers suggest that a multi-pronged approach encompassing adequate surveillance, moderate or low-dose MRA, and K-binding polymers may adequately control serum K in both chronic kidney disease and ESRD patients.

Chronic kidney disease

Chronic kidney disease is a general term for heterogeneous disorders affecting kidney structure and function. The 2002 guidelines for definition and classification of this disease represented an important shift towards its recognition as a worldwide public health problem that should be managed in its early stages by general internists. Disease and management are classified according to stages of disease severity, which are assessed from glomerular filtration rate (GFR) and albuminuria, and clinical diagnosis (cause and pathology). Chronic kidney disease can be detected with routine laboratory tests, and some treatments can prevent development and slow disease progression, reduce complications of decreased GFR and risk of cardiovascular disease, and improve survival and quality of life. In this Seminar we discuss disease burden, recommendations for assessment and management, and future challenges. We emphasise clinical practice guidelines, clinical trials, and areas of uncertainty.

Managing older adults with CKD: individualized versus disease-based approaches

The last decade has seen the evolution and ongoing refinement of a disease-oriented approach to chronic kidney disease (CKD). Disease-oriented models of care assume a direct causal association between observed signs and symptoms and underlying disease pathophysiologic processes. Treatment plans target underlying disease mechanisms with the goal of improving disease-related outcomes. Because average glomerular filtrate rates tend to decrease with age, CKD becomes increasingly prevalent with advancing age and those who meet criteria for CKD are disproportionately elderly. However, several features of geriatric populations may limit the utility of disease-oriented models of care. In older adults, complex comorbid conditions and geriatric syndromes are common; signs and symptoms often do not reflect a single underlying pathophysiologic process; there can be substantial heterogeneity in life expectancy, functional status, and health priorities; and information about the safety and efficacy of recommended interventions often is lacking. For all these reasons, geriatricians have tended to favor an individualized patient-centered model of care over more traditional disease-based approaches. An individualized approach prioritizes patient preferences and embraces the notion that observed signs and symptoms often do not reflect a single unifying disease process and instead reflect the complex interplay between many different factors. This approach emphasizes modifiable outcomes that matter to the patient. Prognostic information related to these and other outcomes generally is used to shape rather than dictate treatment decisions. We argue that an individualized patient-centered approach to care may have more to offer than a traditional disease-based approach to CKD in many older adults.

Management of chronic kidney disease in the elderly

Both chronic kidney disease (CKD) and end-stage renal disease are strongly age related. Although the morbidity and mortality of CKD have significantly improved in recent years because of a greater understanding of its pathophysiology and evidence-based approach to management, the application of this evidence to the elderly CKD patients is often fraught with difficulty. This is because, besides age, the clinical and biological variables that are widely prevalent in the elderly, such as multiple co-morbidities, functional impairments and polypharmacy, and quality of life and functional outcome measures, which are pertinent to this age group, have generally not been incorporated into the available evidence. This paper reviews the current evidence with a view to providing a framework for diagnosing and managing CKD in the elderly. Special references are made to age-related physiological changes in the renal system, assessment of renal function, and management of metabolic complications and end-stage renal disease.

Examining the evidence: a systematic review of the inclusion and analysis of older adults in randomized controlled trials

BACKGROUND

Due to a shortage of studies focusing on older adults, clinicians and policy makers frequently rely on clinical trials of the general population to provide supportive evidence for treating complex, older patients.

OBJECTIVES

To examine the inclusion and analysis of complex, older adults in randomized controlled trials.

REVIEW METHODS

A PubMed search identified phase III or IV randomized controlled trials published in 2007 in JAMA, NEJM, Lancet, Circulation, and BMJ. Therapeutic interventions that assessed major morbidity or mortality in adults were included. For each study, age eligibility, average age of study population, primary and secondary outcomes, exclusion criteria, and the frequency, characteristics, and methodology of age-specific subgroup analyses were reviewed.

RESULTS

Of the 109 clinical trials reviewed in full, 22 (20.2%) excluded patients above a specified age. Almost half (45.6%) of the remaining trials excluded individuals using criteria that could disproportionately impact older adults. Only one in four trials (26.6%) examined outcomes that are considered highly relevant to older adults, such as health status or quality of life. Of the 42 (38.5%) trials that performed an age-specific subgroup analysis, fewer than half examined potential confounders of differential treatment effects by age, such as comorbidities or risk of primary outcome. Trials with age-specific subgroup analyses were more likely than those without to be multicenter trials (97.6% vs. 79.1%, p < 0.01) and funded by industry (83.3% vs. 62.7%, p < 0.05). Differential benefit by age was found in seven trials (16.7%).

CONCLUSION

Clinical trial evidence guiding treatment of complex, older adults could be improved by eliminating upper age limits for study inclusion, by reducing the use of eligibility criteria that disproportionately affect multimorbid older patients, by evaluating outcomes that are highly relevant to older individuals, and by encouraging adherence to recommended analytic methods for evaluating differential treatment effects by age.

Epidemiology and prognostic significance of chronic kidney disease in the elderly--the Three-City prospective cohort study

BACKGROUND

Little is known about normal kidney function level and the prognostic significance of low estimated glomerular filtration rate (eGFR) in the elderly.

METHODS

We determined age and sex distribution of eGFR with both the Modification of Diet in Renal Disease (MDRD) study and the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations in 8705 community-dwelling elderly aged ≥ 65 years and studied its relation to 6-year mortality. In a subsample of 1298 subjects examined at 4 years, we assessed annual eGFR decline and clinically relevant markers including microalbuminuria (3-30 mg/mmol creatinine) with diabetes, proteinuria ≥ 50 mg/mmol, haemoglobin <11 g/L or resistant hypertension despite three drugs.

RESULTS

Median (interquartile range) MDRD eGFR was 78 (68-89) mL/min/1.73 m(2) in men and 74 (65-83) in women; there were 79 (68-87) and 77 (67-85) for CKD-EPI eGFR, respectively. Prevalence of MDRD eGFR <60 mL/min/1.73 m(2) was 13.7% and of CKD-EPI eGFR was 12.9%. After adjustment for several confounders, only those with an eGFR <45 mL/min/1.73 m(2) had significantly higher all-cause and cardiovascular mortality than those with an eGFR of 75-89 mL/min/1.73 m(2) whatever the equation. In the subsample men and women with an MDRD eGFR of 45-59 mL/min/1.73 m(2), 15 and 13% had at least one clinical marker and 15 and 3% had microalbuminuria without diabetes, respectively; these percentages were 41 and 21% and 23 and 10% in men and women with eGFR <45, respectively. Mean MDRD eGFR decline rate was steeper in men than in women, 1.75 versus 1.41 mL/min/1.73 m(2)/year.

CONCLUSIONS

Moderately decreased eGFR is more often associated with clinical markers in men than in women. In both sexes, eGFR <45 mL/min/1.73 m(2) is related to poor outcomes. The CKD-EPI and the MDRD equations provide very similar prevalence and long-term risk estimates in this elderly population.

Renal function and target organ damage in hypertension

Chronic kidney disease (CKD) is frequently observed in patients with arterial hypertension. The same factors that promote the appearance and progression of atherosclerosis can also promote the development of CKD. Two parameters are usually measured to estimate alterations in renal function, the presence of albuminuria, and the estimation of glomerular filtration rate (GFR). Microalbuminuria and a decreased estimated GFR (<60 mL/min/1.73 m(2)) are both accompanied by a significant increase in cardiovascular (CV) risk. Chronic kidney disease can develop all over the cardiorenal continuum and its presence in hypertensive patients with already developed CV disease contributes to a further increase in the development of events and death. Renal protection will in turn obtain CV protection and the treatment to be used is similar to that employed to prevent or to treat established CV disease.

Renin-angiotensin system blockade in older adults with chronic kidney disease: a review of the literature

PURPOSE OF REVIEW

We have reviewed the literature examining the benefits and harms of renin-angiotensin system (RAS) blockade in older adults, using studies which included patients with chronic kidney disease (CKD) as well as those which included a broader patient population.

RECENT FINDINGS

We review the results of key trials which evaluate the impact of RAS blockade on renal outcomes, and those which address the impact of RAS blockade on more global outcomes (cardiovascular events and mortality). Many trials examining renal outcomes of RAS blockade excluded older patients or did not present age-stratified results, whereas trials which examined global outcomes often excluded patients with CKD. Most older patients with CKD have nonproteinuric nondiabetic CKD, thus differing from participants in trials which examined renal outcomes, which often included only patients with diabetes or proteinuria. Most studies did not address alternate outcomes which may carry greatest import for older patients, such as worsening comorbid illness or changes in functional status.

SUMMARY

The role of RAS inhibition for older patients with CKD remains unclear. Information on age-specific effects of RAS blockade on a range of different outcomes among older patients with CKD would improve our ability to assess the benefits and harms of RAS inhibition in this population.

Systolic blood pressure and mortality among older community-dwelling adults with CKD

BACKGROUND

Chronic kidney disease (CKD) is an increasingly common condition, especially in older adults. CKD manifests differently in older versus younger patients, with a risk of death that far outweighs the risk of CKD progressing to the point that dialysis is required. Current CKD guidelines recommend a blood pressure target <130/80 mm Hg for all patients with CKD; however, it is unknown how lower versus higher baseline blood pressures may affect older adults with CKD.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

Older patients (aged ≥ 75 years) with CKD (estimated glomerular filtration rate <60 mL/min/1.73 m(2)) in a community-based health maintenance organization.

PREDICTOR

Baseline systolic blood pressure (SBP) < 130, 130-160 (reference group), and > 160 mm Hg.

OUTCOMES

Participants were followed up for 5 years to examine rates of mortality (primary outcome) and cardiovascular disease hospitalizations (secondary outcome).

RESULTS

At baseline, 3,099 participants (38.5%) had SBP < 130 mm Hg, 3,772 (46.9%) had SBP of 131-160 mm Hg, and 1,171 (14.6%) had SBP >160 mm Hg. A total of 3,734 (46.4%) died and 2,881 (35.8%) were hospitalized. Adjusted HRs for mortality in the groups with SBP < 130 and > 160 mm Hg were 1.22 (95% CI, 1.11-1.34) and 1.06 (95% CI, 0.93-1.22), respectively. Adjusted HRs for cardiovascular hospitalization in these groups were 1.10 (95% CI, 0.99-1.23) and 1.26 (95% CI, 1.09-1.45), respectively.

LIMITATIONS

Although causality should not be inferred from this retrospective analysis, results from this study can generate hypotheses for future randomized controlled trials to investigate the relationship between blood pressure and outcomes in older patients with CKD.

CONCLUSIONS

Our study suggests that lower baseline SBP (≤ 130 mm Hg) may predict poorer outcomes in terms of both mortality and cardiovascular hospitalizations in older adults with CKD. Conversely, higher baseline SBP (> 160 mm Hg) may predict increased risk of cardiovascular hospitalizations, but does not predict mortality. Clinical trials are required to test this hypothesis.