Background

Serum cardiac troponin T (cTnT) is associated with increased risk of heart failure and cardiovascular death in several population settings. We evaluated associations of cTnT levels with cardiac structural and functional abnormalities in a cohort of patients with chronic kidney disease (CKD) without heart failure.

Study design

Cross-sectional.

Setting & participants

Chronic Renal Insufficiency Cohort (CRIC; N=3,243).

Predictor

The primary predictor was cTnT level. Secondary predictors included demographic and clinical characteristics, hemoglobin level, high-sensitivity C-reactive protein level, and estimated glomerular filtration rate using cystatin C.

Outcomes

Echocardiography was used to determine left ventricular (LV) mass and LV systolic and diastolic function.

Measurements

Circulating cTnT was measured in stored sera using the highly sensitive assay. Logistic and linear regression models were used to examine associations of cTnT level with each echocardiographic outcome.

Results

cTnT was detectable in 2,735 (84%) persons; median level was 13.3 (IQR, 7.7-23.8) pg/mL. Compared with undetectable cTnT (<3.0 pg/mL), the highest quartile (23.9-738.7 pg/mL) was approximately 2 times as likely to have LV hypertrophy (OR, 2.43; 95% CI, 1.44-4.09) in the fully adjusted model. cTnT level had a more modest association with LV systolic dysfunction; as a log-linear variable, a significant association was present in the fully adjusted model (OR of 1.4 [95% CI, 1.2-1.7] per 1-log unit; P < 0.001). There was no significant independent association between cTnT level and LV diastolic dysfunction. When evaluated as a screening test, cTnT level functioned only modestly for LV hypertrophy and concentric hypertrophy detection (area under the curve, 0.64 for both), with weaker areas under the curve for the other outcomes.

Limitations

The presence of coronary artery disease was not formally assessed using either noninvasive or angiographic techniques in this study.

Conclusions

In this large CKD cohort without heart failure, detectable cTnT had a strong association with LV hypertrophy, a more modest association with LV systolic dysfunction, and no association with diastolic dysfunction. These findings indicate that circulating cTnT levels in patients with CKD are predominantly an indicator of pathologic LV hypertrophy.

BACKGROUND: Prior studies associating acute kidney injury (AKI) with more rapid subsequent loss of kidney function had methodological limitations, including inadequate control for differences between patients who had AKI and those who did not. OBJECTIVE: To determine whether AKI is independently associated with subsequent kidney function trajectory among patients with chronic kidney disease (CKD). DESIGN: Multicenter prospective cohort study. SETTING: United States. PARTICIPANTS: Patients with CKD (n = 3150). MEASUREMENTS: Hospitalized AKI was defined by a 50% or greater increase in inpatient serum creatinine (SCr) level from nadir to peak. Kidney function trajectory was assessed using estimated glomerular filtration rate (eGFR) based on SCr level (eGFRcr) or cystatin C level (eGFRcys) measured at annual study visits. RESULTS: During a median follow-up of 3.9 years, 433 participants had at least 1 AKI episode. Most episodes (92%) had stage 1 or 2 severity. There were decreases in eGFRcr (-2.30 [95% CI, -3.70 to -0.86] mL/min/1.73 m2) and eGFRcys (-3.61 [CI, -6.39 to -0.82] mL/min/1.73 m2) after AKI. However, in fully adjusted models, the decreases were attenuated to -0.38 (CI, -1.35 to 0.59) mL/min/1.73 m2 for eGFRcr and -0.15 (CI, -2.16 to 1.86) mL/min/1.73 m2 for eGFRcys, and the CI bounds included the possibility of no effect. Estimates of changes in eGFR slope after AKI determined by either SCr level (0.04 [CI, -0.30 to 0.38] mL/min/1.73 m2 per year) or cystatin C level (-0.56 [CI, -1.28 to 0.17] mL/min/1.73 m2 per year) also had CI bounds that included the possibility of no effect. LIMITATIONS: Few cases of severe AKI, no adjudication of AKI cause, and lack of information about nephrotoxic exposures after hospital discharge. CONCLUSION: After pre-AKI eGFR, proteinuria, and other covariables were accounted for, the association between mild to moderate AKI and worsening subsequent kidney function in patients with CKD was small. PRIMARY FUNDING SOURCE: National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health.

BACKGROUND: Adjudication of inpatient AKI in the Systolic Blood Pressure Intervention Trial (SPRINT) was based on billing codes and admission and discharge notes. The purpose of this study was to evaluate the effect of intensive versus standard BP control on creatinine-based inpatient and outpatient AKI, and whether AKI was associated with cardiovascular disease (CVD) and mortality. METHODS: We linked electronic health record (EHR) data from 47 clinic sites with trial data to enable creatinine-based adjudication of AKI. Cox regression was used to evaluate the effect of intensive BP control on the incidence of AKI, and the relationship between incident AKI and CVD and all-cause mortality. RESULTS: A total of 3644 participants had linked EHR data. A greater number of inpatient AKI events were identified using EHR data (187 on intensive versus 155 on standard treatment) as compared with serious adverse event (SAE) adjudication in the trial (95 on intensive versus 61 on standard treatment). Intensive treatment increased risk for SPRINT-adjudicated inpatient AKI (HR, 1.51; 95% CI, 1.09 to 2.08) and for creatinine-based outpatient AKI (HR, 1.40; 95% CI, 1.15 to 1.70), but not for creatinine-based inpatient AKI (HR, 1.20; 95% CI, 0.97 to 1.48). Irrespective of the definition (SAE or creatinine based), AKI was associated with increased risk for all-cause mortality, but only creatinine-based inpatient AKI was associated with increased risk for CVD. CONCLUSIONS: Creatinine-based ascertainment of AKI, enabled by EHR data, may be more sensitive and less biased than traditional SAE adjudication. Identifying ways to prevent AKI may reduce mortality further in the setting of intensive BP control.

Background

People with advanced chronic kidney disease are at risk for the development of end-stage renal disease (ESRD), but also many other adverse outcomes, including cardiovascular disease (CVD) events and death. Determination of risk factors that explain the variability in prognosis and timing of these adverse outcomes can aid patient counseling and medical decision making.

Study design

Prospective research cohort.

Setting & participants

1,798 participants with estimated glomerular filtration rates (eGFRs)<30mL/min/1.73m² in the CRIC Study were followed up for a median of 5.5 years.

Predictors

Age, race, sex, eGFR, proteinuria, diabetes mellitus, body mass index, ejection fraction, systolic blood pressure, history of CVD, and smoking history.

Outcomes

ESRD, CVD (congestive heart failure, stroke, myocardial infarction, and peripheral artery disease), and death.

Results

Baseline age of the cohort was 60 years, 46% were women, and 46% were African American. Although 52.3% of participants progressed to ESRD during follow-up, the path by which this occurred was variable. For example, predicted 1-year probabilities for a hypothetical 60-year-old white woman with eGFR of 30mL/min/1.73m², urine protein excretion of 1.8g/d, and no diabetes or CVD (risk characteristics similar to the average participant) were 3.3%, 4.1%, and 0.3%, for first developing CVD, ESRD, and death, respectively. For a 40-year-old African American man with similar characteristics but higher systolic blood pressure, the corresponding 1-year probabilities were 2.4%, 13.2%, and 0.1%. For all participants, the development of ESRD or CVD increased the risk for subsequent mortality, with no differences by patient race or body mass index.

Limitations

The CRIC population was specifically recruited for kidney disease, and the vast majority had seen a nephrologist.

Conclusions

The prognosis and timing of adverse outcomes in chronic kidney disease vary by patient characteristics. These results may help guide the development of personalized approaches for managing patients with advanced CKD.

Background

It is not clear whether the pattern of kidney function decline in patients with chronic kidney disease (CKD) may relate to outcomes after reaching end-stage renal disease (ESRD). We hypothesize that an abrupt decline in kidney function prior to ESRD predicts early death after initiating maintenance hemodialysis therapy.

Study design

Prospective cohort study.

Setting & participants

The Chronic Renal Insufficiency Cohort (CRIC) Study enrolled men and women with mild to moderate CKD. For this study, we studied 661 individuals who developed chronic kidney failure that required hemodialysis therapy initiation.

Predictors

The primary predictor was the presence of an abrupt decline in kidney function prior to ESRD. We incorporated annual estimated glomerular filtration rates (eGFRs) into a mixed-effects model to estimate patient-specific eGFRs at 3 months prior to initiation of hemodialysis therapy. Abrupt decline was defined as having an extrapolated eGFR≥30mL/min/1.73m(2) at that time point.

Outcomes

All-cause mortality within 1 year after initiating hemodialysis therapy.

Measurements

Multivariable Cox proportional hazards.

Results

Among 661 patients with CKD initiating hemodialysis therapy, 56 (8.5%) had an abrupt predialysis decline in kidney function and 69 died within 1 year after initiating hemodialysis therapy. After adjustment for demographics, cardiovascular disease, diabetes, and cancer, abrupt decline in kidney function was associated with a 3-fold higher risk for death within the first year of ESRD (adjusted HR, 3.09; 95% CI, 1.65-5.76).

Limitations

Relatively small number of outcomes; infrequent (yearly) eGFR determinations; lack of more granular clinical data.

Conclusions

Abrupt decline in kidney function prior to ESRD occurred in a significant minority of incident hemodialysis patients and predicted early death in ESRD.