The impact of acute kidney injury with temporary dialysis on the risk of fracture

Protein-energy wasting significantly increases healthcare utilization and costs among patients with chronic kidney disease: a propensity-score matched cohort study

BACKGROUND

Disease-related malnutrition is highly prevalent, and has prognostic implications for patients with chronic kidney disease (CKD); however, few studies have investigated the impact of malnutrition, or protein-energy wasting (PEW), on healthcare utilization and medical expenditure among CKD patients.

METHODS

Using claim data from the National Health Insurance in Taiwan, this study identified patients with CKD between 2009-2013 and categorized them into those with mild, moderate, or severe CKD. Cases with PEW after CKD was diagnosed were propensity-score matched with controls in a 1:4 ratio. Healthcare resource utilization metrics were compared, including outpatient and emergency department visits, frequency and duration of hospitalization, and the cumulative costs associated with different CKD severity.

RESULTS

From among 347,501 CKD patients, eligible cohorts of 66,872 with mild CKD (49.2%), 27,122 with moderate CKD (19.9%), and 42,013 with severe CKD (30.9%) were selected. Malnourished CKD patients had significantly higher rates of hospitalization (p < .001 for all severities) and re-admission (p = .015 for mild CKD, p = .002 for severe CKD) than non-malnourished controls. Cumulative medical costs for outpatient and emergency visits, and hospitalization, were significantly higher among all malnourished CKD patients than non-malnourished ones (p < .001); total medical costs were also higher among malnourished patients with mild (62.9%), moderate (59.6%), or severe (43.6%) CKD compared to non-malnourished patients (p < .001).

CONCLUSIONS

In a nationally-representative cohort, CKD patients with PEW had significantly more healthcare resource utilization and higher aggregate medical costs than those without, across the spectrum of CKD: preventing PEW in CKD patients should receive high priority if we would like to reduce medical costs.

Vitamin D levels in critically ill patients with acute kidney injury: a protocol for a prospective cohort study (VID-AKI)

INTRODUCTION

Acute kidney injury (AKI) affects more than 50% of critically ill patients. The formation of calcitriol, the active vitamin D metabolite, from the main inactive circulating form, 25-hydroxyvitamin D (25(OH)D), occurs primarily in the proximal renal tubules. This results in a theoretical basis for reduction in levels of calcitriol over the course of an AKI. Vitamin D deficiency is highly prevalent in critically ill adults, and has been associated with increased rates of sepsis, longer hospital stays and increased mortality. The primary objective of this study is to perform serial measurements of 25(OH)D and calcitriol (1,25(OH)₂D), as well as parathyroid hormone (PTH) and fibroblast growth factor 23 (FGF23) levels, in critically ill adult patients with and without AKI, and to determine whether patients with AKI have significantly lower vitamin D metabolite concentrations. The secondary objectives are to describe dynamic changes in vitamin D metabolites, PTH and FGF23 during critical illness; to compare vitamin D metabolite concentrations in patients with AKI with and without renal replacement therapy; and to investigate whether there is an association between vitamin D status and outcomes.

METHODS AND ANALYSIS

230 general adult intensive care patients will be recruited. The AKI arm will include 115 critically ill patients with AKI Kidney Disease Improving Global Outcome stage II or stage III. The comparison group will include 115 patients who require cardiovascular or respiratory support, but who do not have AKI. Serial measurements of vitamin D metabolites and associated hormones will be taken on prespecified days. Patients will be recruited from two large teaching Trusts in England. Data will be analysed using standard statistical methods.

ETHICS AND DISSEMINATION

Ethical approval was obtained. Upon completion, the study team will submit the study report for publication in a peer-reviewed scientific journal and for conference presentation.

TRIAL REGISTRATION NUMBER

NCT02869919; Pre-results.

Benzodiazepine and Z-drug use and risk of pneumonia in patients with chronic kidney disease: A population-based nested case-control study

BACKGROUND

Concerns were raised about pneumonia development from benzodiazepines (BZDs) and Z-drugs, but direct evidence is limited, conflicting and without examining the highly susceptible patients with chronic kidney disease (CKD) nor specifying the risk for different drug utilizations. This study aimed to investigate whether use of BZDs and Z-drugs was each associated with an increased risk of pneumonia in a CKD population.

METHODS

We performed a nested case-control study of 36,880 CKD patients analyzing the Taiwan National Health Insurance Database between 01/1/2000 and 12/31/2011. Among the study cohort, we identified 4,533 cases of pneumonia based on validated disease codes, chest x-ray examination, and prescriptions of respiratory antibiotics, and randomly selected 16,388 controls from risk sets, matched by sex, age, and number of CKD-related hospitalizations. All prescription filling records of BZDs and Z-drugs in the year before the event/index date were analyzed for cases and controls. Conditional logistic regressions were performed to estimate the odds ratios (ORs).

RESULTS

Current use of BZDs was associated with a 1.31-fold (95% CI, 1.18-1.26) increased risk of pneumonia compared to nonuse, but not for recent and past use. The risk from current BZD use was confined to new initiation (adjusted OR, 2.47; 95% CI, 2.02-3.03) or use for ≤ 30 days, and elevated to 2.88-fold (95% CI, 1.87-4.42) with parenteral administration. New initiation and current short-term use of Z-drugs was associated with a 2.94-fold (95% CI, 1.65-5.26) and 1.75-fold (95% CI, 1.13-2.72) increased risk of pneumonia, respectively. The findings were robust to adoption of a case-crossover study that analyzed cases only.

CONCLUSIONS

Use of BZRAs is associated with an increased risk of pneumonia in CKD patients, especially for patients newly initiating BZDs or Z-drugs or those injected with BZDs. Physicians should exercise cautions for signs of pneumonia when prescribing BZDs or Z-drugs to CKD patients.

Ketoanalogues supplementation decreases dialysis and mortality risk in patients with anemic advanced chronic kidney disease

Background

The benefit of alpha-Ketoanalogues (KA) supplementation for chronic kidney disease (CKD) patients that followed low-protein diet (LPD) remains undetermined.

Methods

We extracted longitudinal data for all CKD patients in the Taiwan National Health Insurance from January 1, 2000 through December 31, 2010. A total of 1483 patients with anemic advanced CKD treated with LPD, who started KA supplementation, were enrolled in this study. We analyzed the risks of end stage renal disease and all-cause mortality using Cox proportional hazard models with influential drugs as time-dependent variables.

Results

A total of 1113 events of initiating long-term dialysis and 1228 events of the composite outcome of long-term dialysis or death occurred in patients with advanced CKD after a mean follow-up of 1.57 years. Data analysis suggests KA supplementation is associated with a lower risk for long-term dialysis and the composite outcome when daily dosage is more than 5.5 tablets. The beneficial effect was consistent in subgroup analysis, independent of age, sex, and comorbidities.

Conclusions

Among advanced CKD patients that followed LPD, KA supplementation at an appropriate dosage may substantially reduce the risk of initiating long-term dialysis or of developing the composite outcome. KA supplementation represents an additional therapeutic strategy to slow the progression of CKD.

Meglitinides increase the risk of hypoglycemia in diabetic patients with advanced chronic kidney disease: a nationwide, population-based study

The safety of short-acting meglitinides in diabetic patients with advanced chronic kidney disease (CKD) has not been widely reported. Diabetic patients with advanced CKD who had a serum creatinine level of > 6 mg/dL a hematocrit level of ≦ 28% and received erythropoiesis-stimulating agent treatment between 2000 and 2010, were included in this nationwide study in Taiwan. The outcomes of interest were defined as hypoglycemia and long-term mortality. The risks of hypoglycemia and death were analyzed using Cox proportional hazards models, with end-stage renal disease and anti-diabetic drugs as time-dependent variables. Fresh users and matched non-users of meglitinides (both n = 2,793) were analyzed. The use of meglitinides increased the risk of hypoglycemia (HR, 1.94, p<0.001), as did other anti-diabetic agents. Concomitant use of meglitinide and insuilin will incresase the hypoglycemic risk. (HR, 1.69, p=0.018) Moreover, it was not the use of meglitinides, but the presence of hypoglycemia that predicted mortality. The function curve showed an insignificant trend towards increased hypoglycemic risk in patients aged > 62 and ≤ 33 years from the generalized additive model. This study suggests that the use of short-acting meglitinides could be associated with increased risk of hypoglycemia in diabetic patients with advanced CKD, especially in patients aged > 62 and ≤ 33 years. Meglitinide combined with insulin will increase hypoglycemia in patients with advanced CKD.

Post-ischemic stroke rehabilitation is associated with a higher risk of fractures in older women: A population-based cohort study

BACKGROUND

Rehabilitation can improve physical activity after stroke. However, patients may be more prone to falls and fractures because of balance and gait deficits. Few reports have studied the relationship between rehabilitation and subsequent fractures after ischemic stroke.

OBJECTIVE

To investigate whether post-stroke rehabilitation affects fracture risk.

METHODS

We conducted a population-based retrospective cohort study based on the Taiwan National Health Insurance Research Database. Patients with a newly diagnosed ischemic stroke between 2000 and 2012 were included. After propensity score matching, a total of 8,384 patients were enrolled. Half of the patients (4,192) received post-stroke rehabilitation within 1 month; the other half did not receive any post-stroke rehabilitation. Cox proportional hazards regression model was used to calculate hazard ratios (HRs) for fractures among patients with and without rehabilitation within 1 year after ischemic stroke. Patients were further stratified by sex and age (20-64 and ≥65 years).

RESULTS

Patients receiving post-stroke rehabilitation had a higher incidence of fracture (6.2 per 100 person-years) than those who did not (4.1 per 100 person-years) after adjustment for sociodemographic and coexisting medical conditions [HR = 1.53, 95% confidence interval (CI) = 1.25-1.87, p < 0.001]. The analyses performed after stratifying for sex and age showed that only older women undergoing rehabilitation had a significantly higher risk of fracture (HR = 1.62, 95% CI = 1.21-2.17, p = 0.001).

CONCLUSION

Rehabilitation after ischemic stroke is associated with an increased fracture risk in older women.

Risk of Fracture in Primary Aldosteronism: A Population-Based Cohort Study

Primary aldosteronism (PA) is associated with increased urinary calcium excretion and osteoporosis prevalence. We studied the long-term effect of hyperaldosterone on fracture risk and possible risk mitigation via treatments, by comparing PA patients and their essential hypertension (EH) counterparts extracted by propensity score match. We used a longitudinal population database from the Taiwan National Health Insurance, and used a validated algorithm to identify PA patients diagnosed in 1997-2010. Our sample included 2533 PA patients, including 921 patients with aldosterone-producing adenoma (APA). Our methods for assessing excessive fracture risk included multivariable Cox regression and the competing risk regression. The incidence rate of fracture at any site was 14.4 per 1000 person-years for PA, and 11.2 per 1000 person-years for APA. In contrast, the incidence rate of fracture at any site was 8.3 per 1000 person-years in EH controls for PA, and 6.5 per 1000 person-years in EH controls for APA. Mineralocorticoid receptor antagonist (MRA) treatment might be associated with higher risk of osteoporotic fracture in the whole female PA cohort (subdistribution hazard ratio [SHR] = 2.12, p = 0.008) as well as female APA patients (SHR = 1.15, p = 0.049). As to fracture at any site, MRA treatment was also associated with higher risk; the SHR was 1.88 (p < 0.001) in the whole female PA cohort, and 2.17 (p = 0.019) in female APA patients. PA is tightly associated with higher risk of bone fracture, even in the case where the competing risk of death was controlled. Particularly, female PA patients treated with MRA were confronted with significantly higher risk in bone fracture than their EH controls. © 2017 American Society for Bone and Mineral Research.

Nationwide epidemiology and prognosis of dialysis-requiring acute kidney injury (NEP-AKI-D) study: Design and methods

AIM

Acute kidney injury (AKI) carries an increasing incidence rate worldwide and increases the risk of developing end-stage renal disease (ESRD) as well as the medical expenses during the post-AKI course. The Taiwan Consortium for Acute Kidney Injury and Renal Diseases (CAKs) has thus launched a nationwide epidemiology and prognosis of dialysis-requiring acute kidney injury (NEP-AKI-D) study, which prospectively enrols critically ill patients with AKI. Through thoroughly evaluating the risk and prognostic factors of AKI, we hope to lower the incidence of AKI and ESRD from the perspective of AKI-ESRD interaction.

METHODS

The CAKs includes 30 hospitals which distribute widely through the four geographical regions (north, middle, south, and east) of Taiwan, and have a 1:1 ratio of medical centres to regional hospitals in each region. The NEP-AKI-D study enrols intensive care unit-based AKI patients who receive dialysis in the four seasonal sampled months (October 2014, along with January, April, and July 2015) in the included hospitals. The collected data include demographic information, pertaining laboratory results, dialysis settings and patient outcomes. The data are uploaded in a centre website and will be audited by on-site principal investigators, computer logic gates, and the CAKs staffs. The outcomes of interest are in-hospital mortality, dialysis-dependency and readmission rate within 90 days after discharge.

CONCLUSION

The NEP-AKI-D study enrols a large number of representative AKI patients throughout Taiwan. The results of the current study are expected to provide more insight into the risk and prognostic factors of AKI and further attenuated further chronic kidney disease transition.

Strategies for the optimal timing to start renal replacement therapy in critically ill patients with acute kidney injury

Renal replacement therapy (RRT) is increasingly utilized to support critically ill patients with severe acute kidney injury (AKI). The question of whether and when to start RRT for a critically ill patient with AKI has long troubled clinicians. When severe complications of AKI develop, the need to commence RRT is unambiguous. In the absence of such complications but in the presence of severe AKI, the optimal time and thresholds for starting RRT are uncertain. The majority of existing data have largely been derived from observational studies. These have been limited due to confounding by indication, considerable heterogeneity in case mix and illness severity, and variably applied definitions for both AKI and for how "timing" was anchored relative to starting RRT. It is unclear whether a preemptive or earlier strategy of RRT initiation aimed largely at avoiding complications related to AKI or a more conservative strategy where RRT is started in response to developing complications leads to better patient-centered outcomes and health services use. This question has been the focus of 2 recently completed randomized trials. In this review, we provide an appraisal of available evidence, discuss existing knowledge gaps, and provide perspective on future research that will better inform the optimal timing of RRT initiation in AKI.

Long-term risk of dementia following acute kidney injury: A population-based study

Objective:

Adverse neurological effects may be common following acute kidney injury (AKI). The purpose of our study was to investigate the long-term risk of dementia following AKI and temporary dialysis during hospitalization.

Materials and Methods:

The study was based on data from the National Health Insurance Research Database of Taiwan. Patients 18-year-old and older who were withdrawn from temporary dialysis because of AKI and survived for at least 90 days following discharge were included in our acute-dialysis-recovery group. Patients without AKI and dialysis were the control group. A Cox proportional-hazards regression model was applied to determine the risk of dementia.

Results:

Of 2905 acute-dialysis patients, 689 (23.7%) survived for at least 90 days following recovery from acute dialysis. The Cox proportional-hazards regression model showed that the acute-dialysis-recovery group had an increased long-term risk of dementia (hazard ratio [HR], 2.01; P = 0.01) compared with the control group. The conditional effects plot showed that the risk of dementia was amplified in patients who were older than 58 years. The development of dementia following recovery from acute dialysis was associated with an increase in all-cause mortality (HR, 2.38; P < 0.001).

Conclusions:

Patients with acute dialysis have a greater risk for the subsequent development of dementia after recovery than patients without AKI and dialysis, and patients who develop dementia after recovery from temporary dialysis are at increased risk for mortality.

Long term outcome of Aldosteronism after target treatments

There exists a great knowledge gap in terms of long-term effects of various surgical and pharmacological treatments on outcomes among primary aldosteronism (PA) patients. Using a validated algorithm, we extracted longitudinal data for all PA patients diagnosed in 1997–2010 and treated in the Taiwan National Health Insurance. We identified 3362 PA patients for whom the mean length of follow-up was 5.75 years. PA has higher major cardiovascular events (MACE) than essential hypertension (23.3% vs 19.3%, p = 0.015). Results from the Cox model suggest a strong effect of adrenalectomy on lowering mortality (HR = 0.23 with residual hypertension and 0.21 with resolved hypertension). While need for receptor antagonist (MRA) MRA after diagnosis suggests that a defined daily dose (DDD) of MRA between 12.5 and 50 mg may alleviate risk of death in a U-shape pattern. A specificity test identified patients who has aldosterone producing adenoma (HR = 0.50, p = 0.005) also confirmed adrenalectomy attenuated all-cause mortality. Adrenalectomy decreases long-term all-cause mortality independently from PA cure from hypertension. Prescription corresponding to a DDD between 12.5 and 50 mg may decrease mortality for patients needing MRA. It calls for more attention on early diagnosis, early treatment and prescription of appropriate dosage of MRA for PA patients.

A nationwide survey of clinical characteristics, management, and outcomes of acute kidney injury (AKI) - patients with and without preexisting chronic kidney disease have different prognoses

Acute kidney injury (AKI) is a common complication in hospitalized patients. The International Society of Nephrology implemented the "0 by 25" initiative aimed at preventing deaths from treatable AKI worldwide by 2025 and conducted a global snapshot survey in 2014. We joined in the project and conducted this study to compare the epidemiology, risk factors, and prognosis between patients with pure AKI and those with acute-on-chronic kidney disease (ACKD). In this study, we prospectively collected demographic parameters and data on clinical characteristics, baseline comorbidities, management, and outcomes of 201 AKI patients in 18 hospitals in Taiwan from September 2014 to November 2014. The in-hospital mortality rate was 16%. AKI was mostly attributed to sepsis (52%). Multivariate logistic regression indicated that oliguria was a positive independent predictor of in-hospital mortality, whereas preexisting CKD and exposure to nephrotoxic agents were negative independent predictors. The prevalence of vasopressor use, intensive care unit care, and mortality were significantly higher in pure AKI patients than in ACKD patients. Moreover, serum creatinine (SCr) levels significantly increased within 7 days after AKI diagnosis in nonsurvivors but not in survivors in the pure AKI group. By contrast, SCr levels were persistently lower in nonsurvivors than in survivors in the ACKD group during the same period. We thus determined that the prognosis of ACKD patients differed from that of pure AKI patients. Considering the CKD history in the future AKI staging system may improve prognosis prediction.

Improving outcomes of acute kidney injury survivors

PURPOSE OF REVIEW

Acute kidney injury (AKI) is a common problem in critically ill patients, with long-term health implications that extend beyond hospital discharge. Though they are at a high risk of adverse events, AKI survivors may not be receiving adequate postdischarge medical attention. This review discusses recently published data regarding health outcomes after AKI, the current state of post-AKI care, and potential opportunities to improve outpatient care after AKI.

RECENT FINDINGS

In addition to predisposing to de-novo chronic kidney disease or an exacerbation of previously existing chronic kidney disease, a prior episode of AKI has been linked to subsequent cardiac events, cerebrovascular events, and the need for hospital readmission. Despite this, a population-wide study in Ontario showed that only 40% of patients surviving an episode of dialysis-requiring AKI visited a nephrologist within 90 days of hospital discharge. This care gap is important since outpatient contact with a nephrologist during this critical period was associated with enhanced survival.

SUMMARY

AKI is associated with a number of long-term health effects, and new strategies may be needed to address this emerging public health issue. An ambulatory program dedicated to the postdischarge care of AKI survivors may confer a variety of benefits. Future research is needed to evaluate this model of care.

Establishing a continuum of acute kidney injury - tracing AKI using data source linkage and long-term follow-up: Workgroup Statements from the 15th ADQI Consensus Conference

Background

Acute kidney injury (AKI) is independently associated with the development of chronic kidney disease, endstage kidney disease and increased all-cause and cardiovascular-specific mortality. The severity of the renal insult and the development of multiple AKI episodes increase the risk of occurrence of these outcomes. Despite these long-term effects, only a minority of patients receive nephrologist follow up after an episode of AKI; those that do may have improved outcomes. Furthermore, relatively simple quality improvement strategies have the potential to change this status quo.

Methods

On this background, a working group of the 15^th Acute Dialysis Quality Initiative (ADQI) conference applied the consensus-building process informed by review of English language articles identified through PubMed search to address questions related to the opportunities, methodological requirements and barriers for longitudinal follow-up of patients with AKI in the era of electronic health records and Big Data.

Results

Four consensus statements answering the key questions identified by the working group are developed.

Conclusions

We have identified minimal data elements and potential data sources necessary to trace the natural history of patients from onset of AKI to long-term outcome. Minimum infrastructure and key barriers to achieving these goals are outlined together with proposed solutions.

Risk of liver injury after α-glucosidase inhibitor therapy in advanced chronic kidney disease patients

Although α-glucosidase inhibitors (AGIs) are commonly used for controlling postprandial blood glucose, AGIs-induced liver injuries have been reported. However, the relationship between AGIs and liver injuries in advanced chronic kidney disease (CKD) patients remains unexplored. In this nationwide case-control study, we recruited 1765 advanced diabetic CKD patients, who received AGIs therapy from January 1, 2000 to December 31, 2010 as the study sample and 5295 matched controls. Recent and former AGIs users were defined as patients who received the AGIs prescription for 30–60 d and 30–210 d before the event of liver injury. The risk of AGIs-induced liver injury was examined using time-dependent Cox proportional hazards model. Liver injury occurred in 3.9% of patients in the study group and 3.3% of patients in the control group. AGIs use did not increase the risk of liver injury in advanced CKD patients (P = 0.19). The stratified analysis indicated no increased risk of liver injury in all AGIs-using subgroups (all P > 0.05). The available evidence supports extending the use of AGIs without increasing the risk of liver injury in patients with advanced CKD. Additional randomized controlled trials are warranted to confirm our results.

Long-term remote organ consequences following acute kidney injury

Acute kidney injury (AKI) has been a global health epidemic problem with soaring incidence, increased long-term risks for multiple comorbidities and mortality, as well as elevated medical costs. Despite the improvement of patient outcomes following the advancements in preventive and therapeutic strategies, the mortality rates among critically ill patients with AKI remain as high as 40–60 %. The distant organ injury, a direct consequence of deleterious systemic effects, following AKI is an important explanation for this phenomenon. To date, most evidence of remote organ injury in AKI is obtained from animal models. Whereas the observations in humans are from a limited number of participants in a relatively short follow-up period, or just focusing on the cytokine levels rather than clinical solid outcomes. The remote organ injury is caused with four underlying mechanisms: (1) “classical” pattern of acute uremic state; (2) inflammatory nature of the injured kidneys; (3) modulating effect of AKI of the underlying disease process; and (4) healthcare dilemma. While cytokines/chemokines, leukocyte extravasation, oxidative stress, and certain channel dysregulation are the pathways involving in the remote organ damage. In the current review, we summarized the data from experimental studies to clinical outcome studies in the field of organ crosstalk following AKI. Further, the long-term consequences of distant organ-system, including liver, heart, brain, lung, gut, bone, immune system, and malignancy following AKI with temporary dialysis were reviewed and discussed.

Pentoxifylline Decreases Dialysis Risk in Patients With Advanced Chronic Kidney Disease

Few studies evaluated the effects of pentoxifylline on hard endpoints in patients with predialysis stage 5 chronic kidney disease (CKD). Thus, we tried to explore the effects of pentoxifylline and its interaction with renin-angiotensin-aldosterone system (RAAS) blockade on the development of endstage renal disease (ESRD) and mortality. This nationwide cohort study retrospectively included patients who had a serum creatinine level of >6 mg/dL and received erythropoiesis-stimulating agents (ESAs) between 2000 and 2010. We analyzed 7,366 pentoxifylline users and 7,366 propensity score-matched nonusers. Using Cox proportional hazard models, pentoxifylline reduced the risks of ESRD and the composite renal outcome but not that of mortality. In terms of the risks of developing ESRD, pentoxifylline alone exerted a comparable beneficial effect to combined therapy with an RAAS inhibitor and greater renoprotection than RAAS inhibitor monotherapy. This study suggests pentoxifylline is efficacious in slowing progression to ESRD in patients with predialysis stage 5 CKD.

Promoting Kidney Function Recovery in Patients with AKI Requiring RRT

AKI requiring RRT is associated with high mortality, morbidity, and long-term consequences, including CKD and ESRD. Many patients never recover kidney function; in others, kidney function improves over a period of many weeks or months. Methodologic constraints of the available literature limit our understanding of the recovery process and hamper adequate intervention. Current management strategies have focused on acute care and short-term mortality, but new data indicate that long-term consequences of AKI requiring RRT are substantial. Promotion of kidney function recovery is a neglected focus of research and intervention. This lack of emphasis on recovery is illustrated by the relative paucity of research in this area and by the lack of demonstrated effective management strategies. In this article the epidemiologic implications of kidney recovery after AKI requiring RRT are discussed, the available literature and its methodologic constraints are reviewed, and strategies to improve the understanding of factors that affect kidney function recovery are proposed. Measures to promote kidney function recovery are a serious unmet need, with a great potential to improve short- and long-term patient outcomes.

Fibroblast growth factor 23 in acute kidney injury

PURPOSE OF REVIEW

To review the emerging literature on changes in fibroblast growth factor 23 (FGF23) levels in the setting of acute kidney injury (AKI).

RECENT FINDINGS

Studies suggest that FGF23 levels are elevated in patients with AKI and correlate with increased risk of death or need for dialysis in adults, or prolonged ventilation time and higher fluid gain in children. Animal studies have shown that the cause behind this FGF23 increase is multifactorial and includes increased production in bone and decreased clearance, but not vitamin D or parathyroid hormone (PTH) activated pathways. Interestingly, FGF23 levels are found to be mildly elevated even in hospitalized patients without kidney injury, although this observation may be limited to only c-terminal FGF23 fragments. The prognostic implications of an elevated FGF23 value in patients with AKI need to be confirmed in larger cohorts and evaluated for long-term outcomes such as the development of new chronic kidney disease (CKD) or CKD progression, as well as cardiovascular disease, similar to the studies of FGF23 in the prevalent CKD population.

SUMMARY

FGF23 levels are elevated in patients with AKI and are associated with morbidity and mortality in small human studies. Mechanistic work in animals suggests that the elevation is independent of PTH or vitamin D signaling pathways. Much work remains to understand the physiology behind FGF23 elevation and the long-term effects of FGF23 in AKI.

Long-term risk of upper gastrointestinal hemorrhage after advanced AKI

BACKGROUND AND OBJECTIVES

There are few reports on temporary dialysis-requiring AKI as a risk factor for future upper gastrointestinal bleeding (UGIB). This study sought to explore the long-term association between dialysis-requiring AKI and UGIB.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This nationwide cohort study used data from the Taiwan National Health Insurance Research Database. Patients who recovered from dialysis-requiring AKI and matched controls were selected from hospitalized patients age ≥18 years between 1998 and 2006. The cumulative incidences of long-term de novo UGIB were calculated, and the risk factors of UGIB and mortality were identified using time-varying Cox proportional hazard models adjusted for subsequent CKD and ESRD after AKI.

RESULTS

A total of 4565 AKI-recovery patients and the same number of matched patients without AKI were analyzed. After a median follow-up time of 2.33 years (interquartile range, 0.97-4.81 years), the incidence rates of UGIB were 50 (by stringent criterion) and 69 (by lenient criterion) per 1000 patient-years in the AKI-recovery group and 31 (by stringent criterion) and 48 (by lenient criterion) per 1000 patient-years in the non-AKI group (both P<0.001). When compared with patients in the non-AKI group, the multivariate hazard ratio (HR) for UGIB was 1.30 (95% confidence interval [95% CI], 1.14 to 1.48) for dialysis-requiring AKI, 1.83 (95% CI, 1.53 to 2.20) for time-varying CKD, and 2.31 (95% CI, 1.92 to 2.79) for time-varying ESRD (all P<0.001). Finally, the risk for long-term mortality increased after UGIB (HR, 1.24; 95% CI, 1.12 to 1.38) and dialysis-requiring AKI (HR, 1.66; 95% CI, 1.54 to 1.78).

CONCLUSIONS

Recovery from dialysis-requiring AKI was associated with future UGIB and mortality.

Long-term outcomes after dialysis-requiring acute kidney injury

AKI-dialysis patients had a higher incidence of long-term ESRD and mortality than the patients without AKI. The patients who recovered from dialysis were associated with a lower incidence of long-term ESRD and mortality than in the patients who still required dialysis.

Administrative data on diagnosis and mineralocorticoid receptor antagonist prescription identified patients with primary aldosteronism in Taiwan

OBJECTIVES

To develop algorithms of locating patients with primary aldosteronism (PA) using insurance reimbursement data and to validate the algorithms using medical charts.

STUDY DESIGN AND SETTING

We extracted National Health Insurance (NHI) reimbursement data and medical charts in seven enrolled hospitals and analyzed diagnosis-related information for 1999-2010. The NHI codes PA as 255.1x, using the International Classification of Diseases, Ninth Revision, Clinical Modification. Confirmation of PA was based on suppression tests.

RESULTS

We reviewed medical charts for 1,094 cases with at least one PA diagnosis. PA was confirmed for 563 cases. Compared with patients with essential hypertension, PA patients had higher systolic blood pressure, higher aldosterone, lower renin activity, and lower potassium level (all P-values <0.05). An algorithm based on PA diagnosis reported in at least one hospital stay or three outpatient visits had modest performance (sensitivity = 0.94 and specificity = 0.20). The best additional condition for the algorithm was use of mineralocorticoid receptor antagonist (MRA; sensitivity = 0.89 and specificity = 0.88).

CONCLUSION

Using information on PA diagnosis and MRA prescription reported in insurance claims data can precisely locate PA patients in high-risk groups. This algorithm can construct a reliable PA sample for conducting research in various fields, including epidemiology and clinical practice.

Dialysis-requiring acute kidney injury increases risk of long-term malignancy: a population-based study

BACKGROUND

Acute kidney injury (AKI) is gaining worldwide attention recently, emerging as a major public health threat. However, the association between the development of AKI and subsequent malignancy has not been studied before.

METHODS

We conducted a population study based on the Taiwan National Health Insurance database, using 1,000,000 representative database during 2000-2008. All patients' survival to discharge from index hospitalization with recovery from dialysis-requiring AKI were identified (recovery group), and matched with those without recovery and those without AKI, at a 1:1:1 ratio.

RESULTS

We identified 625 individuals more than 18 years old [352 male (56.5%); mean age, 63.3 years] in recovery group and matched 625 individuals in each group. During a mean followed-up of 3.7 years, the incidences of new-onset malignancy were 4.2, 2.9, and 2.6 per 100 person-year among the non-recovery, the recovery, and the non-AKI group, respectively. After adjustment, the recovery group was more likely to develop long-term de novo malignancy than those without AKI [hazard ratio (HR) 1.44, 95% confidence interval (CI) 1.02-2.03; p = 0.04], while less likely than those who did not recover (HR 0.66, 95% CI 0.45-0.98; p = 0.04).

CONCLUSIONS

Dialysis-requiring AKI can post a long-term risk of de novo malignancy for those who survive from the initial insult. Even patients who have recovered from dialysis still carry a significantly higher possibility of developing malignancy than those without AKI episode.