Does ALLHAT change the management of hypertension in chronic kidney disease?

Worsening Kidney Function Is the Major Mechanism of Heart Failure in Hypertension: The ALLHAT Study

OBJECTIVES

The authors aimed to quantify the extent to which the effect of antihypertensive drugs on incident heart failure (HF) is mediated by their effect on kidney function.

BACKGROUND

The authors hypothesized that the dynamic change in kidney function is the mechanism behind differences in the rate of incident HF in ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) participants randomized to lisinopril and chlorthalidone, in comparison with those randomized to amlodipine and doxazosin.

METHODS

Causal mediation analysis of ALLHAT data (1994 to 2002) included participants with available baseline and 24- to 48-month estimated glomerular filtration rate (eGFR) (N = 27,918; mean age 66 ± 7.4 years; 32.4% Black, 56.3% men). Change in eGFR was the mediator. Incident symptomatic HF was the primary outcome. Hospitalized/fatal HF was the secondary outcome. Linear regression (for mediator) and logistic regression (for outcome) analyses were adjusted for demographics, cardiovascular disease, and risk factors.

RESULTS

There were 1,769 incident HF events, including 1,359 hospitalized/fatal HF events. In fully adjusted causal mediation analysis, the relative change in eGFR mediated 18% of the effect of chlorthalidone, and 33% of lisinopril on incident symptomatic HF, and 25% of the effect of chlorthalidone, and 41% of lisinopril on hospitalized/fatal HF. In participants with diabetes, the relative change in eGFR mediated nearly 50% of the effect of lisinopril on incident symptomatic HF, whereas in diabetes-free participants, only 17%.

CONCLUSIONS

On the risk difference scale, change in eGFR accounts for up to 50% of the mechanism by which antihypertensive medications affect HF. (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial [ALLHAT]; NCT00000542).

Antihypertensive treatment for kidney transplant recipients

BACKGROUND

In some nontransplant populations, effects of different antihypertensive drug classes vary. Relative effects in kidney transplant recipients are uncertain.

OBJECTIVES

To assess comparative effects of different classes of antihypertensive agents in kidney transplant recipients.

SEARCH STRATEGY

MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, conference proceedings and reference lists of identified studies were searched.

SELECTION CRITERIA

Randomised controlled trials of any antihypertensive agent applied to kidney transplant recipients for at least two weeks were included.

DATA COLLECTION AND ANALYSIS

Data was extracted by two investigators independently. Study quality, transplant outcomes and other patient centred outcomes were assessed using random effects meta-analysis. Risk ratios (RR) for dichotomous outcomes and mean difference (MD) for continuous outcomes, both with 95% confidence intervals (CI) were calculated. Stratified analyses and meta-regression were used to investigate heterogeneity.

MAIN RESULTS

We identified 60 studies, enrolling 3802 recipients. Twenty-nine studies (2262 participants) compared calcium channel blockers (CCB) to placebo/no treatment, 10 studies (445 participants) compared angiotensin converting enzyme inhibitors (ACEi) to placebo/no treatment and seven studies (405 participants) compared CCB to ACEi. CCB compared to placebo/no treatment (plus additional agents in either arm as required) reduced graft loss (RR 0.75, 95% CI 0.57 to 0.99) and improved glomerular filtration rate (GFR), (MD, 4.45 mL/min, 95% CI 2.22 to 6.68). Data on ACEi versus placebo/no treatment were inconclusive for GFR (MD -8.07 mL/min, 95% CI -18.57 to 2.43), and variable for graft loss, precluding meta-analysis. In direct comparison with CCB, ACEi decreased GFR (MD -11.48 mL/min, 95% CI -5.75 to -7.21), proteinuria (MD -0.28 g/24 h, 95% CI -0.47 to -0.10), haemoglobin (MD -12.96 g/L, 95% CI -5.72 to -10.21) and increased hyperkalaemia (RR 3.74, 95% CI 1.89 to 7.43). Graft loss data were inconclusive (RR 7.37, 95% CI 0.39 to 140.35). Other drug comparisons were compared in small numbers of participants and studies.

AUTHORS' CONCLUSIONS

These data suggest that CCB may be preferred as first line agents for hypertensive kidney transplant recipients. ACEi have some detrimental effects in kidney transplant recipients. More high quality studies reporting patient centred outcomes are required.

Development of end stage renal disease following an acute cardiac event

We determined the rate and risk factors for end-stage renal disease (ESRD) in consecutive patients discharged after a cardiac event in a large, unbiased Canadian cohort that receives universal health coverage. A total of 8236 adults hospitalized over a 2 year period were followed for up to 7.5 years and the incidence of ESRD and mortality determined. Of these, 113 reached ESRD (stage 5). Patients with moderate (stage 3) and severe (stage 4) renal insufficiency were more likely to develop ESRD than those patients at stage 1 or 2. However, patients with moderate renal insufficiency were 78.6 times more likely to die than to develop ESRD. Absolute rates of progression to ESRD per 100-patient years were 0.08 at stages 1 and 2, 0.17 at stage 3 and 4.27 at stage 4. Age, diabetes, hypertension and congestive heart failure also predicted ESRD. We found that patients with stage 4 disease are at high risk of ESRD after a cardiac admission while those at stage 3 are far more likely to die than to develop ESRD.