Seon Ha Baek

Mild decrease in estimated glomerular filtration rate and proteinuria are associated with all-cause and cardiovascular mortality in the general population

BACKGROUND A recent collaborative meta-analysis by Kidney Disease: Improving Global Outcomes reported that an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m(2) and an albumin-to-creatinine ratio of ≥ 10 mg/g were independent predictors for mortality in the general population. However, selection bias, heterogeneity of the cohorts and measurement issues could be limitations. METHODS We analyzed the relationship of eGFR and proteinuria with mortality in the Korean general population, represented by 112,115 participants, aged ≥ 20 years, who had a voluntary health check-up with homogenous calibration of creatinine measurement from 2003 to 2009. Proteinuria (trace or more) was determined by urine dipstick. RESULTS eGFR and proteinuria were independently associated with all-cause mortality (ACM) and cardiovascular mortality (CVM), and progressive increases in risks for mortality were noted according to eGFR level and the presence of proteinuria. Compared with eGFR 90-105 mL/min/1.73 m(2), hazard ratio (HRs) for ACM were 1.60 [95% confidence interval (CI) 1.12-2.30] for eGFR 60-74 mL/min/1.73 m(2) and 3.54 (2.20-5.68) for eGFR <60 mL/min/1.73 m(2) in participants with no proteinuria. In participants with proteinuria, HRs for ACM were 2.10 (1.41-3.12) for eGFR 75-89 mL/min/1.73 m(2), 2.30 (1.50-3.53) for eGFR 60-74 mL/min/1.73 m(2) and 3.77 (2.15-6.38) for eGFR <60 mL/min/1.73 m(2). Similar findings were observed for CVM. CONCLUSIONS eGFR <75 mL/min/1.73 m(2) and urine dipstick trace or more were independent risk factors of ACM and CVM. The risks of adverse outcomes are greater in the general population with mild renal impairment or mild proteinuria.

Renal adverse effects of sunitinib and its clinical significance: a single-center experience in Korea

Background/Aims Sunitinib is an oral multitargeted tyrosine kinase inhibitor used mainly for the treatment of metastatic renal cell carcinoma. The renal adverse effects (RAEs) of sunitinib have not been investigated. The aim of this study was to determine the incidence and risk factors of RAEs (proteinuria [PU] and renal insufficiency [RI]) and to investigate the relationship between PU and antitumor efficacy. Methods We performed a retrospective review of medical records of patients who had received sunitinib for more than 3 months. Results One hundred and fifty-five patients (mean age, 58.7 ± 12.6 years) were enrolled, and the mean baseline creatinine level was 1.24 mg/dL. PU developed in 15 of 111 patients, and preexisting PU was aggravated in six of 111 patients. Only one patient developed typical nephrotic syndrome. Following discontinuation of sunitinib, PU was improved in 12 of 17 patients but persisted in five of 17 patients. RI occurred in 12 of 155 patients, and the maximum creatinine level was 3.31 mg/dL. RI improved in two of 12 patients but persisted in 10 of 12 patients. Risk factors for PU were hypertension, dyslipidemia, and chronic kidney disease. Older age was a risk factor for RI. The median progression-free survival was significantly better for patients who showed PU. Conclusions The incidence of RAEs associated with sunitinib was lower than those of previous reports. The severity of RAEs was mild to moderate, and partially reversible after cessation of sunitinib. We suggest that blood pressure, urinalysis, and renal function in patients receiving sunitinib should be monitored closely.

Incident Chronic Kidney Disease and Newly Developed Complications Related to Renal Dysfunction in an Elderly Population during 5 Years: A Community-Based Elderly Population Cohort Study

Background Few studies have evaluated the association between incident chronic kidney disease (CKD) and related complications, especially in elderly population. We attempted to verify the association between GFR and concurrent CKD complications and elucidate the temporal relationship between incident CKD and new CKD complications in a community-based prospective elderly cohort. Method We analyzed the available data from 984 participants in the Korean Longitudinal Study on Health and Aging. Participants were categorized into 6 groups according to eGFR at baseline examination (≥90, 75–89, 60–74, 45–59, 30–44, and <30 ml/min/1.73 m2). Result The mean age of study population was 76 ± 9.1 years and mean eGFR was 72.3 ± 17.0 ml/min/1.73 m2. Compared to eGFR group 1, the odds ratio (OR) for hypertension was 2.363 (95% CI, 1.299-4.298) in group 4, 5.191 (2.074-12.995) in group 5, and 13.675 (1.611-115.806) in group 6; for anemia, 7.842 (2.265-27.153) in group 5 and 13.019 (2.920-58.047) in group 6; for acidosis, 69.580 (6.770-715.147) in group 6; and for hyperkalemia, 19.177 (1.798-204.474) in group 6. Over a 5-year observational period, CKD developed in 34 (9.6%) among 354 participants with GFR ≥ 60 ml/min/1.73 m2 at basal examination. The estimated mean number of new complications according to analysis of co-variance was 0.52 (95% CI, 0.35–0.68) in subjects with incident CKD and 0.24 (0.19–0.29) in subjects without CKD (p = 0.002). Subjects with incident CKD had a 2.792-fold higher risk of developing new CKD complications. A GFR level of 52.4 ml/min/1.73 m2 (p = 0.032) predicted the development of a new CKD complication with a 90% sensitivity. Conclusion In an elderly prospective cohort, CKD diagnosed by current criteria is related to an increase in the number of concurrent CKD complications and the development of new CKD complications.

Outcomes of Predialysis Nephrology Care in Elderly Patients Beginning to Undergo Dialysis

Background The proportion of elderly patients beginning to undergo dialysis is increasing globally. Whether early referral (ER) of elderly patients is associated with favorable outcomes remains under debate. We investigated the influence of referral timing on the mortality of elderly patients. Methods We retrospectively assessed mortality in 820 patients aged ≥70 years with end-stage renal disease (ESRD) who initiated hemodialysis at a tertiary university hospital between 2000 and 2010. Mortality data was obtained from the time of dialysis initiation until December 2010. We assigned patients to one of two groups according to the time of their first encounters with nephrologists: ER (≥ 3 months) and late referral (LR; < 3 months). Results During a mean follow-up period of 25.1 months, the ER group showed a 24% reduced risk of long-term mortality relative to the LR group (HR = 0.760, P = 0.009). Rate of reduction in 90-day mortality for ER patients was 58% (HR = 0.422, P=0.012). However, the statistical significance of the difference in mortality rates between ER and LR group was not observed across age groups after 90 days. Old age, LR, central venous catheter, high white blood cell count and corrected Ca level, and lower levels of albumin, creatinine, hemoglobin, and sodium were significantly associated with increased risk of mortality. Conclusions Timely referral was also associated with reduced mortality in elderly ESRD patients who initiated hemodialysis. In particular, the initial 90-day mortality reduction in ER patients contributed to mortality differences during the follow-up period.

Impact of parathyroidectomy on allograft outcomes in kidney transplantation

We performed retrospective, multi‐center study of the impacts of parathyroidectomy (PTX) after or before kidney transplantation on allograft outcomes. A total of 63 patients who underwent PTX after kidney transplantation were identified. Deterioration in eGFR by more than 25% at 1 month after PTX occurred in 20% of the patients. The baseline eGFR was significantly lower in impairment group than nonimpairment group [adjusted odds ratio (OR) 0.87, 95% confidence interval (CI) 0.77–0.99, P = 0.033]. Low iPTH concentration after PTX was also a significant risk factor for the renal impairment (OR 0.96, CI 0.94–0.99, P = 0.009). A total of 37 patients who underwent PTX before transplantation were identified. Thirty‐six percent of the patients had persistent hyperparathyroidism by 1 year after transplantation. A high iPTH level before PTX was a significant risk factor for persistent post‐transplant hyperparathyroidism (adjusted OR 1.002, CI 1.000–1.005, P = 0.039). Finally, eGFR values during the first 5 years after transplantation were significantly lower in the patients who underwent PTX at less than 1 year after transplantation, than the pretransplant PTX patients (P = 0.032). As PTX after kidney transplantation has a risk of deterioration of allograft function, pretransplant PTX should be considered for patients with severe hyperparathyroidism, who could undergo post‐transplant PTX.

Impact of Electronic Acute Kidney Injury (AKI) Alerts With Automated Nephrologist Consultation on Detection and Severity of AKI: A Quality Improvement Study

BACKGROUND Several electronic alert systems for acute kidney injury (AKI) have been introduced. However, their clinical benefits require further investigation. STUDY DESIGN Before-and-after quality improvement study. SETTING & PARTICIPANTS A tertiary teaching hospital in Korea, which adopted an AKI alert system on June 1, 2014. Before and after launch of the alert system, 1,884 and 1,309 patients with AKI were included in the usual-care and alert groups, respectively. QUALITY IMPROVEMENT PLAN Implementation of an AKI alert system through which clinicians could generate automated consultations to the nephrology division for all hospitalized patients. OUTCOMES Primary outcomes included overlooked AKI events, defined as not measuring the follow-up creatinine value, and the consultation pattern of clinicians. Secondary outcomes were severe AKI events; AKI recovery, defined based on the creatinine-based criterion; and patient mortality. MEASUREMENTS ORs for events of overlooked AKI, early consultation, and severe AKI were calculated with logistic regression. AKI recovery rate and patient mortality were assessed using Cox regression. RESULTS After introduction of the alert system, the odds of overlooked AKI events were significantly lower (adjusted OR, 0.40; 95% CI, 0.30-0.52), and the odds of an early consultation with a nephrologist were greater (adjusted OR, 6.13; 95% CI, 4.80-7.82). The odds of a severe AKI event was reduced after implementation of the alerts (adjusted OR, 0.75; 95% CI, 0.64-0.89). Furthermore, the likelihood of AKI recovery was improved in the alert group (adjusted HR, 1.70; 95% CI, 1.53-1.88). Mortality was not affected by the AKI alert system (adjusted HR, 1.07; 95% CI, 0.68-1.68). LIMITATIONS Possible unreported differences between the alert and usual-care groups. CONCLUSIONS Implementation of the AKI alert system was associated with beneficial effects in terms of an improved rate of recovery from AKI. Therefore, widespread adoption of such systems could be considered in general hospitals.

Elevated baseline potassium level within reference range is associated with worse clinical outcomes in hospitalised patients

The clinical significance of elevated baseline serum potassium (K+) levels in hospitalised patients is rarely described. Hence, we performed a retrospective study assessing the significance of elevated K+ levels in a one-year admission cohort. Adult patients without hypokalaemia or end-stage renal disease were included. Adverse outcomes were all-cause mortality, hospital-acquired acute kidney injury, and events of arrhythmia. In total, 17,777 patients were included in the study cohort, and a significant difference (P < 0.001) was observed in mortality according to baseline serum K+ levels. The adjusted hazard ratios (HRs) and associated 95% confidence intervals (CIs) of all-cause mortality for K+ levels above the reference range of 3.6–4.0 mmol/L were as follows: 4.1–4.5 mmol/L, adjusted HR 1.075 (95% CI 0.981–1.180); 4.6–5.0 mmol/L, adjusted HR 1.261 (1.105–1.439); 5.1–5.5 mmol/L, adjusted HR 1.310 (1.009–1.700); >5.5 mmol/L, adjusted HR 2.119 (1.532–2.930). Moreover, the risks of in-hospital acute kidney injury and arrhythmia were higher in patients with serum K+ levels above 4.0 mmol/L and 5.5 mmol/L, respectively. In conclusion, increased serum K+ levels, including mild elevations may be related to worse prognosis. Close monitoring and prompt correction of underlying causes or hyperkalaemia itself is warranted for admitted patients.

Effects of acute kidney injury and chronic kidney disease on long-term mortality after coronary artery bypass grafting

BACKGROUND Both acute kidney injury (AKI) and chronic kidney disease (CKD) are important issues in patients undergoing coronary artery bypass grafting (CABG), particularly with regard to mortality. However, their synergistic or discrete effects on long-term mortality remain unresolved. METHODS A total of 1,899 patients undergoing CABG were retrospectively analyzed. The adjusted hazard ratios for all-cause mortality were calculated after stratifying the timeframes. To evaluate the synergistic effects between AKI and CKD, the relative excess risk due to interaction was applied. RESULTS The presence of AKI, CKD, or both increased the hazard ratios for mortality, compared with the absence of both: AKI alone, 1.84 (1.464-2.319); CKD alone, 2.46 (1.735-3.478); and AKI and CKD together, 3.21 (2.301-4.488). However, the relationships with mortality were different between AKI and CKD, according to the timeframes: AKI primarily affected early mortality, particularly within 3 years, whereas CKD had a relatively constant effect on both the early and late periods. When the parameters from the relative excess risk due to interaction were obtained, there was a synergistic additive effect on early mortality between AKI and CKD. CONCLUSIONS The relationships with mortality after CABG were different between AKI and CKD. However, their effects were not exclusive but synergistic.

Proteinuria and hematuria are associated with acute kidney injury and mortality in critically ill patients: a retrospective observational study

BackgroundProteinuria and hematuria are both important health issues; however, the nature of the association between these findings and acute kidney injury (AKI) or mortality remains unresolved in critically ill patients.MethodsProteinuria and hematuria were measured by a dipstick test and scored using a scale ranging from a negative result to 3+ in 1883 patients admitted to the intensive care unit. AKI was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. The odds ratios (ORs) for AKI and 3-year mortality were calculated after adjustment for multiple covariates according to the degree of proteinuria or hematuria. For evaluating the synergistic effect on mortality among proteinuria, hematuria, and AKI, the relative excess risk due to interaction (RERI) was used.ResultsProteinuria and hematuria increased the ORs for AKI: the ORs of proteinuria were 1.66 (+/−), 1.86 (1+), 2.18 (2+), and 4.74 (3+) compared with non-proteinuria; the ORs of hematuria were 1.31 (+/−), 1.58 (1+), 2.63 (2+), and 2.52 (3+) compared with non-hematuria. The correlations between the mortality risk and proteinuria or hematuria were all significant and graded (Ptrend < 0.001). There was a relative excess risk of mortality when both AKI and proteinuria or hematuria were considered together: the synergy indexes were 1.30 and 1.23 for proteinuria and hematuria, respectively.ConclusionsProteinuria and hematuria are associated with the risks of AKI and mortality in critically ill patients. Additionally, these findings had a synergistic effect with AKI on mortality.

Small Increases in Plasma Sodium Are Associated with Higher Risk of Mortality in a Healthy Population

Elevated blood pressure (BP) is the most common cause of cardiovascular disease. Salt intake has a strong influence on BP, and plasma sodium (pNa) is increased with progressive increases in salt intake. However, the associations with pNa and BP had been reported inconsistently. We evaluated the association between pNa and BP, and estimated the risks of all-cause-mortality according to pNa levels. On the basis of data collected from health checkups during 1995-2009, 97,009 adult subjects were included. Positive correlations between pNa and systolic BP, diastolic BP, and pulse pressure (PP) were noted in participants with pNa ≥138 mM/L (P<0.001). In participants aged ≥50 yr, SBP, DBP, and PP were positively associated with pNa. In participants with metabolic syndrome components, the differences in SBP and DBP according to pNa were greater (P<0.001). A cumulative incidence of mortality was increased with increasing pNa in women aged ≥50 yr during the median 4.2-yr-follow-up (P<0.001). In women, unadjusted risks for mortality were increased according to sodium levels. After adjustment, pNa ≥145 mM/L was related to mortality. The positive correlation between pNa and BP is stronger in older subjects, women, and subjects with metabolic syndrome components. The incidence and adjusted risks of mortality increase with increasing pNa in women aged ≥50 yr.