Nish Chaturvedi

Association of estimated glomerular filtration rate and albuminuria with all-cause and cardiovascular mortality in general population cohorts: a collaborative meta-analysis.

BACKGROUND Substantial controversy surrounds the use of estimated glomerular filtration rate (eGFR) and albuminuria to define chronic kidney disease and assign its stages. We undertook a meta-analysis to assess the independent and combined associations of eGFR and albuminuria with mortality. METHODS In this collaborative meta-analysis of general population cohorts, we pooled standardised data for all-cause and cardiovascular mortality from studies containing at least 1000 participants and baseline information about eGFR and urine albumin concentrations. Cox proportional hazards models were used to estimate hazard ratios (HRs) for all-cause and cardiovascular mortality associated with eGFR and albuminuria, adjusted for potential confounders. FINDINGS The analysis included 105,872 participants (730,577 person-years) from 14 studies with urine albumin-to-creatinine ratio (ACR) measurements and 1,128,310 participants (4,732,110 person-years) from seven studies with urine protein dipstick measurements. In studies with ACR measurements, risk of mortality was unrelated to eGFR between 75 mL/min/1.73 m(2) and 105 mL/min/1.73 m(2) and increased at lower eGFRs. Compared with eGFR 95 mL/min/1.73 m(2), adjusted HRs for all-cause mortality were 1.18 (95% CI 1.05-1.32) for eGFR 60 mL/min/1.73 m(2), 1.57 (1.39-1.78) for 45 mL/min/1.73 m(2), and 3.14 (2.39-4.13) for 15 mL/min/1.73 m(2). ACR was associated with risk of mortality linearly on the log-log scale without threshold effects. Compared with ACR 0.6 mg/mmol, adjusted HRs for all-cause mortality were 1.20 (1.15-1.26) for ACR 1.1 mg/mmol, 1.63 (1.50-1.77) for 3.4 mg/mmol, and 2.22 (1.97-2.51) for 33.9 mg/mmol. eGFR and ACR were multiplicatively associated with risk of mortality without evidence of interaction. Similar findings were recorded for cardiovascular mortality and in studies with dipstick measurements. INTERPRETATION eGFR less than 60 mL/min/1.73 m(2) and ACR 1.1 mg/mmol (10 mg/g) or more are independent predictors of mortality risk in the general population. This study provides quantitative data for use of both kidney measures for risk assessment and definition and staging of chronic kidney disease. FUNDING Kidney Disease: Improving Global Outcomes (KDIGO), US National Kidney Foundation, and Dutch Kidney Foundation.Background A comprehensive evaluation of the independent and combined associations of estimated glomerular filtration rate (eGFR) and albuminuria with mortality is required for assessment of the impact of kidney function on risk in the general population, with implications for improving the definition and staging of chronic kidney disease (CKD).

Cardiorenal end points in a trial of aliskiren for type 2 diabetes

BACKGROUND This study was undertaken to determine whether use of the direct renin inhibitor aliskiren would reduce cardiovascular and renal events in patients with type 2 diabetes and chronic kidney disease, cardiovascular disease, or both. METHODS In a double-blind fashion, we randomly assigned 8561 patients to aliskiren (300 mg daily) or placebo as an adjunct to an angiotensin-converting-enzyme inhibitor or an angiotensin-receptor blocker. The primary end point was a composite of the time to cardiovascular death or a first occurrence of cardiac arrest with resuscitation; nonfatal myocardial infarction; nonfatal stroke; unplanned hospitalization for heart failure; end-stage renal disease, death attributable to kidney failure, or the need for renal-replacement therapy with no dialysis or transplantation available or initiated; or doubling of the baseline serum creatinine level. RESULTS The trial was stopped prematurely after the second interim efficacy analysis. After a median follow-up of 32.9 months, the primary end point had occurred in 783 patients (18.3%) assigned to aliskiren as compared with 732 (17.1%) assigned to placebo (hazard ratio, 1.08; 95% confidence interval [CI], 0.98 to 1.20; P=0.12). Effects on secondary renal end points were similar. Systolic and diastolic blood pressures were lower with aliskiren (between-group differences, 1.3 and 0.6 mm Hg, respectively) and the mean reduction in the urinary albumin-to-creatinine ratio was greater (between-group difference, 14 percentage points; 95% CI, 11 to 17). The proportion of patients with hyperkalemia (serum potassium level, ≥6 mmol per liter) was significantly higher in the aliskiren group than in the placebo group (11.2% vs. 7.2%), as was the proportion with reported hypotension (12.1% vs. 8.3%) (P<0.001 for both comparisons). CONCLUSIONS The addition of aliskiren to standard therapy with renin-angiotensin system blockade in patients with type 2 diabetes who are at high risk for cardiovascular and renal events is not supported by these data and may even be harmful. (Funded by Novartis; ALTITUDE ClinicalTrials.gov number, NCT00549757.).

Effect of lisinopril on progression of retinopathy in normotensive people with type 1 diabetes

BACKGROUND Retinopathy commonly occurs in people with type 1 diabetes. Strict glycaemic control can decrease development and progression of retinopathy only partially. Blood pressure is also a risk factor for microvascular complications. Antihypertensive therapy, especially with inhibitors of angiotensin-converting enzyme (ACE), can slow progression of nephropathy, but the effects on retinopathy have not been established. We investigated the effect of lisinopril on retinopathy in type 1 diabetes. METHODS As part of a 2-year randomised double-blind placebo-controlled trial, we took retinal photographs at baseline and follow-up (24 months) in patients aged 20-59 in 15 European centres. Patients were not hypertensive, and were normoalbuminuric (85%) or microalbuminuric. Retinopathy was classified from photographs on a five-level scale (none to proliferative). FINDINGS The proportion of patients with retinopathy at baseline was 65% (117) in the placebo group and 59% (103) in the lisinopril group (p = 0.2). Patients on lisinopril had significantly lower HbA1c at baseline than those on placebo (6.9% vs 7.3 p = 0.05). Retinopathy progressed by at least one level in 21 (13.2%) of 159 patients on lisinopril and 39 (23.4%) of 166 patients on placebo (odds ratio 0.50 [95% CI 0.28-0.89], p = 0.02). This 50% reduction was the same when adjusted for centre and glycaemic control (0.55 [0.30-1.03], p = 0.06). Lisinopril also decreased progression by two or more grades (0.27 [0.07-1.00], p = 0.05), and progression to proliferative retinopathy (0.18 [0.04-0.82], p = 0.03). Progression was not associated with albuminuric status at baseline. Treatment reduced retinopathy incidence (0.69 [0.30-1.59], p = 0.4). INTERPRETATION Lisinopril may decrease retinopathy progression in non-hypertensive patients who have type 1 diabetes with little or no nephropathy. These findings need to be confirmed before changes to clinical practice can be advocated.

Randomised placebo-controlled trial of lisinopril in normotensive patients with insulin-dependent diabetes and normoalbuminuria or microalbuminuria

Summary Background Renal disease in people with insulin-dependent diabetes (IDDM) continues to pose a major health threat. Inhibitors of angiotensin-converting enzyme (ACE) slow the decline of renal function in advanced renal disease, but their effects at earlier stages are unclear, and the degree of albuminuria at which treatment should start is not known. Methods We carried out a randomised, double-blind, placebo-controlled trial of the ACE inhibitor lisinopril in 530 men and women with IDDM aged 20–59 years with normoalbuminuria or microalbuminuria. Patients were recruited from 18 European centres, and were not on medication for hypertension. Resting blood pressure at entry was at least 75 and no more than 90 mm hg diastolic, and no more than 155 mm hg systolic. Urinary albumin excretion rate (AER) was centrally assessed by means of two overnight urine collections at baseline, 6, 12, 18, and 24 months. Findings There were no differences in baseline characteristics by treatment group; mean AER was 8.0 μg/min in both groups; and prevalence of microalbuminuria was 13% and 17% in the placebo and lisinopril groups, respectively. On intention-to-treat analysis at 2 years, AER was 2.2 μg/min lower in the lisinopril than in the placebo group, a percentage difference of 18.8% (95% CI 2·0–32·7, p=0·03), adjusted for baseline AER and centre, absolute difference 2.2 μg/min. In people with normoalbuminuria, the treatment difference was 1·0 μg/min (12·7% [−2·9 to 26·0], p=0·1). In those with microalbuminuria, however, the treatment difference was 34.2 μg/min (49·7% [−14·5 to 77·9], p=0·1; for interaction, p=0·04). For patients who completed 24 months on the trial, the final treatment difference in AER was 38·5 μg/min in those with microalbuminuria at baseline (p=0·001), and 0·23 μg/min in those with normoalbuminuria at baseline (p=0·6). There was no treatment difference in hypoglycaemic events or in metabolic control as assessed by glycated haemoglobin. Interpretation Lisinopril slows the progression of renal disease in normotensive IDDM patients with little or no albuminuria, though greatest effect was in those with microalbuminuria (AER ≥20 μg/min). Our results show that lisinopril does not increase the risk of hypoglycaemic events in IDDM.

Effect of candesartan on prevention (DIRECT-Prevent 1) and progression (DIRECT-Protect 1) of retinopathy in type 1 diabetes: randomised, placebo-controlled trials

BACKGROUND Results of previous studies suggest that renin-angiotensin system blockers might reduce the burden of diabetic retinopathy. We therefore designed the DIabetic REtinopathy Candesartan Trials (DIRECT) Programme to assess whether candesartan could reduce the incidence and progression of retinopathy in type 1 diabetes. METHODS Two randomised, double-blind, parallel-design, placebo-controlled trials were done in 309 centres worldwide. Participants with normotensive, normoalbuminuric type 1 diabetes without retinopathy were recruited to the DIRECT-Prevent 1 trial and those with existing retinopathy were recruited to DIRECT-Protect 1, and were assigned to candesartan 16 mg once a day or matching placebo. After 1 month, the dose was doubled to 32 mg. Investigators and participants were unaware of the treatment allocation status. The primary endpoints were incidence and progression of retinopathy and were defined as at least a two-step and at least a three-step increase on the Early Treatment Diabetic Retinopathy Study (ETDRS) scale, respectively. These trials are registered with ClinicalTrials.gov, numbers NCT00252733 for DIRECT-Prevent 1 and NCT00252720 for DIRECT-Protect 1. FINDINGS 1421 participants (aged 18-50 years) were randomly assigned to candesartan (n=711) or to placebo (n=710) in DIRECT-Prevent 1, and 1905 (aged 18-55 years) to candesartan (n=951) or to placebo (n=954) in DIRECT-Protect 1. Incidence of retinopathy was seen in 178 (25%) participants in the candesartan group versus 217 (31%) in the placebo group. Progression of retinopathy occurred in 127 (13%) participants in the candesartan group versus 124 (13%) in the placebo group. Hazard ratio (HR for candesartan vs placebo) was 0.82 (95% CI 0.67-1.00, p=0.0508) for incidence of retinopathy and 1.02 (0.80-1.31, p=0.85) for progression of retinopathy. The post-hoc outcome of at least a three-step increase for incidence yielded an HR of 0.65 (0.48-0.87, p=0.0034), which was attenuated but still significant after adjustment for baseline characteristics (0.71, 0.53-0.95, p=0.046). Final ETDRS level was more likely to have improved with candesartan treatment in both DIRECT-Prevent 1 (odds 1.16, 95% CI 1.05-1.30, p=0.0048) and DIRECT-Protect 1 (1.12, 95% CI 1.01-1.25, p=0.0264). Adverse events did not differ between the treatment groups. INTERPRETATION Although candesartan reduces the incidence of retinopathy, we did not see a beneficial effect on retinopathy progression.

Effect of candesartan on progression and regression of retinopathy in type 2 diabetes (DIRECT-Protect 2): a randomised placebo-controlled trial

BACKGROUND Diabetic retinopathy remains a leading cause of visual loss in people of working age. We examined whether candesartan treatment could slow the progression and, secondly, induce regression of retinopathy in people with type 2 diabetes. METHODS We did a randomised, double-blind, parallel-group, placebo-controlled trial in 309 centres worldwide. We recruited normoalbuminuric, normotensive, or treated hypertensive people with type 2 diabetes with mild to moderately severe retinopathy and assigned them to candesartan 16 mg once a day or placebo. After a month, the dose was doubled to 32 mg once per day. Investigators and patients were unaware of the treatment allocation status. Progression of retinopathy was the primary endpoint, and regression was a secondary endpoint. Analysis was by intention to treat. The trial is registered with ClinicalTrials.gov, number NCT00252694. FINDINGS 1905 participants (aged 37-75 years) were randomised to candesartan (n=951) or placebo (n=954). 161 (17%) patients in the candesartan group and 182 (19%) in the placebo group had progression of retinopathy by three steps or more on the Early Treatment Diabetic Retinopathy Study scale. The risk of progression of retinopathy was non-significantly reduced by 13% in patients on candesartan compared with those on placebo (hazard ratio [HR] 0.87, 95% CI 0.70-1.08, p=0.20). Regression on active treatment was increased by 34% (1.34, 1.08-1.68, p=0.009). HRs were not attenuated by adjustment for baseline risk factors or changes in blood pressure during the trial. An overall change towards less severe retinopathy by the end of the trial was observed in the candesartan group (odds 1.17, 95% CI 1.05-1.30, p=0.003). Adverse events did not differ between the treatment groups. INTERPRETATION Treatment with candesartan in type 2 diabetic patients with mild to moderate retinopathy might induce improvement of retinopathy.

Aliskiren Trial in Type 2 Diabetes Using Cardio-Renal Endpoints (ALTITUDE): rationale and study design

BACKGROUND Patients with type 2 diabetes are at increased risk of macro- and microvascular disease, and the presence of albuminuria and/or reduced kidney function further enhances macrovascular risk. Angiotensin-converting-enzyme inhibitors reduce both macro- and microvascular events, yet the residual renal and cardiovascular risk still remains high. Aliskiren a novel oral direct renin inhibitor that unlike ACEi and ARBs, lowers plasma renin activity, angiotensin I and angiotensin II levels, may thereby provide greater benefit compared to ACEi or ARB alone. METHODS The primary objective of the ALTITUDE trial is to determine whether aliskiren 300 mg once daily, reduces cardiovascular and renal morbidity and mortality compared with placebo when added to conventional treatment (including ACEi or ARB). ALTITUDE is an international, randomized, double-blind, placebo-controlled, parallel-group study, which will include three categories of high-risk patients with type 2 diabetes (aged > or =35 years): those with either urinary albumin/creatinine ratio (UACR) > or =200 mg/g; microalbuminuria (UACR) > or =20 <200 mg/g and eGFR > or =30 <60 mL/min/1.73 m2; and thirdly, those with a history of cardiovascular disease and eGFR > or =30 <60 mL/min/1.73 m2 with or without microalbuminuria. ALTITUDE is an event driven trial that aims to randomize 8600 patients with a planned follow-up time of 48 months. The primary outcome measure is time to first event for the composite endpoint of cardiovascular death, resuscitated death, myocardial infarction, stroke, unplanned hospitalization for heart failure, onset of end-stage renal disease or doubling of baseline serum creatinine concentration. Secondary endpoints include a composite CV endpoint and a composite renal endpoint. CONCLUSION ALTITUDE will determine whether dual RAAS blockade with the direct renin inhibitor aliskiren in combination with an ACEi or ARB will reduce major morbidity and mortality in a broad range of high-risk patients with type 2 diabetes.

Abnormalities of Retinal Microvascular Structure and Risk of Mortality From Ischemic Heart Disease and Stroke

Abnormalities of the retinal microcirculation are found in hypertension and diabetes and predict cardiovascular mortality. This study examined the relationship between abnormalities of the retinal microvasculature and death from ischemic heart disease (IHD) and stroke. A population-based, nested case-control study was undertaken within the Beaver Dam Eye Study. Subjects (43 to 74 years) who died of IHD (n=126) or stroke (n=28) over a 10-year period were age and gender matched with controls subjects (n=528; case:control matching, ≈1:4). Retinal photographs of cases and controls were digitized and analyzed using a computer-based technique. Increased risk of IHD death was associated with a suboptimal relationship of arteriolar diameters at bifurcation (P=0.02 unadjusted) and decreased retinal arteriolar tortuosity (P=0.011 unadjusted). These associations remained significant after adjustment for age, sex, past history of cardiovascular disease, and other known cardiovascular risk factors. Increased arteriolar length:diameter ratio, a measure of generalized arteriolar narrowing, was associated with increased stroke mortality (P=0.02 unadjusted). This association was independent of age and gender but was attenuated by adjustment for systolic blood pressure (P=0.15). Other quantitative measures of the retinal microvascular network (eg, venular tortuosity and arteriolar and venular bifurcation angle) were not associated with death from IHD or stroke. Retinal microvascular abnormalities are predictive of death from IHD and stroke. A detailed assessment of the retinal microvascular network from digitized photographs may be useful in the noninvasive assessment of target organ damage and cardiovascular risk.

Prevalence of overweight and obesity and their association with hypertension and diabetes mellitus in an Indo-Asian population.

Background: The associations of body mass index (BMI) and chronic disease may differ between Indo-Asian and Western populations. We used Indo-Asian-specific definitions of overweight and obesity to determine the prevalence of these problems in Pakistan and studied the sensitivity and specificity of BMI cutoff values for an association with hypertension and diabetes mellitus. Methods: We analyzed data for 8972 people aged 15 years or more from the National Health Survey of Pakistan (1990–1994). People considered overweight or obese were those with a BMI of 23 kg/m2 or greater, and those considered obese as having a BMI of 27 kg/m2 or greater. We built multivariable models and performed logistic regression analysis. Results: The prevalence of overweight and obesity, weighted to the general Pakistani population, was 25.0% (95% confidence interval [CI] 21.8%–28.2%). The prevalence of obesity was 10.3% (95% CI 7.0%–13.2%). The factors independently and significantly associated with overweight and obesity included greater age, being female, urban residence, being literate, and having a high (v. low) economic status and a high (v. low) intake of meat. With receiver operating characteristic curves, we found that the use of even lower BMI cutoff values (21.2 and 22.1 kg/m2 for men and 21.2 and 22.9 kg/m2 for women) than those recommended for an Indo-Asian population yielded the optimal areas under the curve for an association with hypertension and diabetes, respectively. Interpretation: A quarter of the population of Pakistan would be classified as overweight or obese with the use of Indo-Asian-specific BMI cutoff values. Optimal identification of those at risk of hypertension and diabetes and healthy targets may require the use of even lower BMI cutoff values than those already proposed for an Indo-Asian population.

Effect of Candesartan on Microalbuminuria and Albumin Excretion Rate in Diabetes: Three Randomized Trials

BACKGROUND Microalbuminuria in diabetes is strongly predictive of nephropathy, end-stage renal disease, and premature cardiovascular morbidity and mortality. Effective preventive therapies are therefore a clinical priority. OBJECTIVE To determine whether the angiotensin-receptor blocker candesartan compared with placebo affects microalbuminuria incidence or rate of change in albuminuria in type 1 and type 2 diabetes. DESIGN 3 randomized trials of the DIRECT (Diabetic Retinopathy Candesartan Trials) Program. SETTING 309 secondary care centers. PATIENTS 3326 and 1905 patients with type 1 and type 2 diabetes, respectively. Most were normotensive, and all had normoalbuminuria (median urinary albumin excretion rate, 5.0 microg/min). INTERVENTION Candesartan, 16 mg/d increasing to 32 mg/d, versus placebo. Assignment was done centrally using an interactive voice-response system. Patients, caregivers, and researchers were blinded to treatment assignment. During a median follow-up of 4.7 years, 793 patients discontinued therapy and 63 were lost to follow-up. MEASUREMENTS Urinary albumin excretion rate, assessed annually by 2 overnight collections; if it was 20 microg/min or greater, then 2 further collections were done. The primary end point was new microalbuminuria (3 or 4 collections of urinary albumin excretion rate >or=20 microg/min). The secondary end point was rate of change in albuminuria. RESULTS Individual and pooled results of the 3 trials showed that candesartan had little effect on risk for microalbuminuria (pooled hazard ratio, 0.95 [95% CI, 0.78 to 1.16]; P = 0.60). Pooled results showed that the annual rate of change in albuminuria was 5.53% lower (CI, 0.73% to 10.14%; P = 0.024) with candesartan than with placebo. LIMITATIONS Investigators recruited mainly normotensive patients or patients with well-controlled hypertension who were at low overall vascular risk, which resulted in a low rate of microalbuminuria. Studies were powered for retinal and not renal end points. CONCLUSION Candesartan, 32 mg/d, for 4.7 years did not prevent microalbuminuria in mainly normotensive patients with type 1 or type 2 diabetes.