Physician adjudication of angioedema diagnosis codes in a population of patients with heart failure prescribed angiotensin-converting enzyme inhibitor therapy.

PURPOSE: Our objective was to calculate the positive predictive value (PPV) of the ICD-9 diagnosis code for angioedema when physicians adjudicate the events by electronic health record review. Our secondary objective was to evaluate the inter-rater reliability of physician adjudication. METHODS: Patients from the Cardiovascular Research Network previously diagnosed with heart failure who were started on angiotensin-converting enzyme inhibitors (ACEI) during the study period (July 1, 2006 through September 30, 2015) were included. A team of two physicians per participating site adjudicated possible events using electronic health records for all patients coded for angioedema for a total of five sites. The PPV was calculated as the number of physician-adjudicated cases divided by all cases with the diagnosis code of angioedema (ICD-9-CM code 995.1) meeting the inclusion criteria. The inter-rater reliability of physician teams, or kappa statistic, was also calculated. RESULTS: There were 38 061 adults with heart failure initiating ACEI in the study (21 489 patient-years). Of 114 coded events that were adjudicated by physicians, 98 angioedema events were confirmed for a PPV of 86% (95% CI: 80%, 92%). The kappa statistic based on physician inter-rater reliability was 0.65 (95% CI: 0.47, 0.82). CONCLUSIONS: ICD-9 diagnosis code of 995.1 (angioneurotic edema, not elsewhere classified) is highly predictive of angioedema in adults with heart failure exposed to ACEI.

Individuality of the plasma sodium concentration.

Older literature has suggested that the plasma sodium concentration is not individual, that it is neither intrinsic to an individual nor reproducible, longitudinally. We recently observed that the plasma sodium concentration is heritable. Because demonstrable heritability requires individuality of the relevant phenotype, we hypothesized that the plasma sodium concentration was substantially individual. In two large health plan-based cohorts, we demonstrated individuality of the plasma sodium concentration over a 10-yr interval; the intraclass correlation coefficient (ICC) averaged 0.4-0.5. The individuality of plasma sodium increased significantly with age. Plasma sodium individuality was equal to or only slightly less than that for plasma glucose but was less than the individuality for creatinine. The individuality of plasma sodium was further confirmed by comparing the Pearson correlation coefficient for within-individual versus between-individual pairs of sodium determinations and via application of the agreement index. Furthermore, the distribution of all sodium determinations for all participants within a population was similar to the distribution for the mean sodium concentration for individuals within that population. Therefore, the near-normal distribution of plasma sodium measurements within a population is likely not attributable to assay-specific factors but rather to genuine and durable biological variability in the osmotic set point. In aggregate, these data strongly support the individuality of the plasma sodium concentration. They further indicate that serial plasma sodium values for any given individual tend to cluster around a patient-specific set point and that these set points vary among individuals.

Clostridium difficile infection, Colorado and the northwestern United States, 2007.

To determine the incidence of Clostridium difficile infection during 2007, we examined infection in adult inpatient and outpatient members of a managed-care organization. Incidence was 14.9 C. difficile infections per 10,000 patient-years. Extrapolating this rate to US adults, we estimate that 284,875 C. difficile infections occurred during 2007.

Clinician's use of automated reports of estimated glomerular filtration rate: a qualitative study.

BACKGROUND: There is a growing awareness in primary care of the importance of identifying patients with chronic kidney disease (CKD) so that they can receive appropriate clinical care; one method that has been widely embraced is the use of automated reporting of estimated glomerular filtration rate (eGFR) by clinical laboratories. We undertook a qualitative study to examine how clinicians use eGFR in clinical decision making, patient communication issues, barriers to use of eGFR, and suggestions to improve the clinical usefulness of eGFR reports. METHODS: Our study used qualitative methods with structured interviews among primary care clinicians including both physicians and allied health providers, recruited from Kaiser Permanente Northwest, a non-profit health maintenance organization. RESULTS: We found that clinicians generally held favorable views toward eGFR reporting but did not use eGFR to replace serum creatinine in their clinical decision-making. Clinicians used eGFR as a tool to help identify CKD, educate patients about their kidney function and make treatment decisions. Barriers noted by several clinicians included a desire for greater education regarding care for patients with CKD and tools to facilitate discussion of eGFR findings with patients. CONCLUSIONS: The manner in which clinicians use eGFRs appears to be more complex than previously understood, and our study illustrates some of the efforts that might be usefully undertaken (e.g. specific clinician education) when encouraging further promulgation of eGFR reporting and usage.

Predicting costs of care in heart failure patients.

BACKGROUND: Identifying heart failure patients most likely to suffer poor outcomes is an essential part of delivering interventions to those most likely to benefit. We sought a comprehensive account of heart failure events and their cumulative economic burden by examining patient characteristics that predict increased cost or poor outcomes. METHODS: We collected electronic medical data from members of a large HMO who had a heart failure diagnosis and an echocardiogram from 1999-2004, and followed them for one year. We examined the role of demographics, clinical and laboratory findings, comorbid disease and whether the heart failure was incident, as well as mortality. We used regression methods appropriate for censored cost data. RESULTS: Of the 4,696 patients, 8% were incident. Several diseases were associated with significantly higher and economically relevant cost changes, including atrial fibrillation (15% higher), coronary artery disease (14% higher), chronic lung disease (29% higher), depression (36% higher), diabetes (38% higher) and hyperlipidemia (21% higher). Some factors were associated with costs in a counterintuitive fashion (i.e. lower costs in the presence of the factor) including age, ejection fraction and anemia. But anemia and ejection fraction were also associated with a higher death rate. CONCLUSIONS: Close control of factors that are independently associated with higher cost or poor outcomes may be important for disease management. Analysis of costs in a disease like heart failure that has a high death rate underscores the need for economic methods to consider how mortality should best be considered in costing studies.

Proteinuria among patients with chronic kidney disease: a performance measure for improving patient outcomes.

BACKGROUND: In an effort to improve identification and treatment of patients with chronic kidney disease (CKD), the National Kidney Foundation (NKF) developed the Kidney Disease Quality Outcomes Initiative (KDQOI) clinical practice guidelines, which include measurement of proteinuria among all patients with CKD who are not receiving chronic dialysis therapy. Encouraging dissemination and utilization of these guidelines may be enhanced by the development of performance measures. The question of whether adequate evidence exists to advocate for the measurement of proteinuria in CKD as a performance measure was explored. METHODS: The US Preventive Services Task Force "chain of evidence" framework was used to guide evidence synthesis from the systematic review. Five questions were applied to specific links in the evidence chain: (1) Is there direct evidence that testing for proteinuria improves health outcomes? (2) What is the yield of testing, in terms of both accuracy and reliability of the test and the prevalence of undiagnosed proteinuria? (3) What adverse effects result from testing a person for proteinuria? (4) Does treatment of proteinuria as a result of testing provide an incremental benefit in health outcomes? and (5) What adverse effects result from treating a person for proteinuria? The systematic search specifically targeted meta-analyses and systematic reviews. FINDINGS: The systematic review revealed no direct evidence that testing for proteinuria among patients with CKD reduced incidence of end-stage renal disease (ESRD). However, the strong links between testing, treatment, and outcome suggest a correlation between proteinuria testing and ESRD. CONCLUSIONS: Current evidence suggests that proteinuria testing (using the albumin-to-creatinine ratio [ACR]) among patients with CKD would be an appropriate health care quality performance measure for improving patient outcomes.

Lower estimated glomerular filtration rate and higher albuminuria are associated with mortality and end-stage renal disease. A collaborative meta-analysis of kidney disease population cohorts.

We studied here the independent associations of estimated glomerular filtration rate (eGFR) and albuminuria with mortality and end-stage renal disease (ESRD) in individuals with chronic kidney disease (CKD). We performed a collaborative meta-analysis of 13 studies totaling 21,688 patients selected for CKD of diverse etiology. After adjustment for potential confounders and albuminuria, we found that a 15 ml/min per 1.73 m² lower eGFR below a threshold of 45 ml/min per 1.73 m² was significantly associated with mortality and ESRD (pooled hazard ratios (HRs) of 1.47 and 6.24, respectively). There was significant heterogeneity between studies for both HR estimates. After adjustment for risk factors and eGFR, an eightfold higher albumin- or protein-to-creatinine ratio was significantly associated with mortality (pooled HR 1.40) without evidence of significant heterogeneity and with ESRD (pooled HR 3.04), with significant heterogeneity between HR estimates. Lower eGFR and more severe albuminuria independently predict mortality and ESRD among individuals selected for CKD, with the associations stronger for ESRD than for mortality. Thus, these relationships are consistent with CKD stage classifications based on eGFR and suggest that albuminuria provides additional prognostic information among individuals with CKD.

Predicting the risk of end-stage renal disease in the population-based setting: a retrospective case-control study.

BACKGROUND: Previous studies of predictors of end-stage renal disease (ESRD) have limitations: (1) some focused on patients with clinically recognized chronic kidney disease (CKD); (2) others identified population-based patients who developed ESRD, but lacked earlier baseline clinical measures to predict ESRD. Our study was designed to address these limitations and to identify the strength and precision of characteristics that might predict ESRD pragmatically for decision-makers--as measured by the onset of renal replacement therapy (RRT). METHODS: We conducted a population-based, retrospective case-control study of patients who developed ESRD and started RRT. We conducted the study in a health maintenance organization, Kaiser Permanente Northwest (KPNW). The case-control study was nested within the adult population of KPNW members who were enrolled during 1999, the baseline period. Cases and their matched controls were identified from January 2000 through December 2004. We evaluated baseline clinical characteristics measured during routine care by calculating the adjusted odds ratios and their 95% confidence intervals after controlling for matching characteristics: age, sex, and year. RESULTS: The rate of RRT in the cohort from which we sampled was 58 per 100,000 person-years (95% CI, 53 to 64). After excluding patients with missing data, we analyzed 350 cases and 2,114 controls. We identified the following characteristics that predicted ESRD with odds ratios ≥ 2.0: eGFR<60 mL/min/1.73 m(2) (OR = 20.5; 95% CI, 11.2 to 37.3), positive test for proteinuria (OR = 5.0; 95% CI, 3.5 to 7.1), hypertension (OR = 4.5; 95% CI, 2.5 to 8.0), gout/positive test for uric acid (OR = 2.5; 95% CI, 1.8 to 3.5), peripheral vascular disease (OR = 2.2; 95% CI, 1.4 to 3.6), congestive heart failure (OR = 2.1; 95% CI, 1.4 to 3.3), and diabetes (OR = 2.1; 95% CI, 1.5 to 2.9). CONCLUSIONS: The clinical characteristics needed to predict ESRD--for example, to develop a population-based, prognostic risk score--were often documented during routine care years before patients developed ESRD and required RRT.

Comparison of a Kidney Replacement Therapy Risk Score Developed in Kaiser Permanente Northwest vs Estimated Glomerular Filtration Rate in Advanced Chronic Kidney Disease Using Decision Curve Analysis.

INTRODUCTION: Use of kidney replacement therapy (KRT) prediction models for guiding arteriovenous fistula (AVF) referrals in advanced chronic kidney disease (CKD) is unknown. We aimed to compare a hypothetical approach using a KRT prediction model developed in Kaiser Permanente Northwest to estimated glomerular filtration rate (eGFR) for AVF referrals. METHODS: Our retrospective cohort consisted of patients with stage G4 CKD in Kaiser Permanente Northwest followed by nephrology. Two-year KRT risk was calculated at each nephrology visit up to 2 years from entrance into cohort based on a previously published model. We calculated sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) based on several 2-year KRT risk and eGFR cutoffs for outcome of hemodialysis at 18 months. We compared an approach of AVF referral using 2-year KRT risk and eGFR cutoffs using decision curve analysis. RESULTS: Two-year KRT risk better discriminated progression to hemodialysis compared to eGFR < 15 mL/min (AUC 0.60 vs 0.69 at 2-year KRT risk > 20% and 0.69 at 2-year KRT risk > 40%, p = 0.003 and 0.006, respectively) but not to eGFR of 20 mL/min (AUC 0.64, p = 0.16 and 0.19, respectively). Decision curve analysis showed that AVF referral guided by 2-year KRT risk score resulted in higher net benefit compared to eGFR at low thresholds for referral. CONCLUSION: In stage G4 CKD, a 2-year KRT risk model better predicted progression to KRT at 18 months compared to an eGFR of 15 mL/min but not to 20 mL/min and may improve timely referral for AVF placement in patients at lower thresholds for referral.

Predicted risk of renal replacement therapy at arteriovenous fistula referral in chronic kidney disease.

BACKGROUND AND OBJECTIVES: Optimal timing of arteriovenous fistula placement in chronic kidney disease remains difficult and contributes to high central venous catheter use at initial hemodialysis. We tested whether a prediction model for progression to renal replacement therapy developed at Kaiser Permanente Northwest may help guide decisions about timing of referral for arteriovenous fistula placement. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS: A total of 205 chronic kidney disease stage 4 patients followed by nephrology referred for arteriovenous fistula placement were followed for up to 2 years. Patients were censored if they died or discontinued Kaiser Permanente Northwest coverage. Survival analyses were performed for overall progression to renal replacement therapy divided by quartiles based on 2-year risk for renal replacement therapy and estimated glomerular filtrate rate at time of referral. RESULTS: By 2 years, 60% progressed to renal replacement therapy and 11% had died. 80% in the highest risk versus 36% in the lowest risk quartile progressed to renal replacement therapy (predicted risk 84% vs 17%). 75% in the lowest estimated glomerular filtrate rate versus 56% in the highest estimated glomerular filtrate rate quartile progressed to renal replacement therapy (mean estimated glomerular filtrate rate 13 mL/min vs 21 mL/min). The hazard ratio was significantly higher for each consecutive higher renal replacement therapy quartile risk while for estimated glomerular filtrate rate, the hazard ratio was only significantly higher for the lowest compared to the highest quartile. The extreme quartile risk ratio was higher for 2-year risk for renal replacement therapy compared to estimated glomerular filtrate rate (4.0 vs 2.4). CONCLUSION: In patients with chronic kidney disease stage 4 referred for arteriovenous fistula placement, 2-year renal replacement therapy risk better discriminated progression to renal replacement therapy compared to estimated glomerular filtrate rate at time of referral.

Renin-angiotensin system blockade in older adults with chronic kidney disease: a review of the literature.

PURPOSE OF REVIEW: We have reviewed the literature examining the benefits and harms of renin-angiotensin system (RAS) blockade in older adults, using studies which included patients with chronic kidney disease (CKD) as well as those which included a broader patient population. RECENT FINDINGS: We review the results of key trials which evaluate the impact of RAS blockade on renal outcomes, and those which address the impact of RAS blockade on more global outcomes (cardiovascular events and mortality). Many trials examining renal outcomes of RAS blockade excluded older patients or did not present age-stratified results, whereas trials which examined global outcomes often excluded patients with CKD. Most older patients with CKD have nonproteinuric nondiabetic CKD, thus differing from participants in trials which examined renal outcomes, which often included only patients with diabetes or proteinuria. Most studies did not address alternate outcomes which may carry greatest import for older patients, such as worsening comorbid illness or changes in functional status. SUMMARY: The role of RAS inhibition for older patients with CKD remains unclear. Information on age-specific effects of RAS blockade on a range of different outcomes among older patients with CKD would improve our ability to assess the benefits and harms of RAS inhibition in this population.

Systolic blood pressure and mortality among older community-dwelling adults with CKD.

BACKGROUND: Chronic kidney disease (CKD) is an increasingly common condition, especially in older adults. CKD manifests differently in older versus younger patients, with a risk of death that far outweighs the risk of CKD progressing to the point that dialysis is required. Current CKD guidelines recommend a blood pressure target <130/80 mm Hg for all patients with CKD; however, it is unknown how lower versus higher baseline blood pressures may affect older adults with CKD. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: Older patients (aged ≥ 75 years) with CKD (estimated glomerular filtration rate <60 mL/min/1.73 m(2)) in a community-based health maintenance organization. PREDICTOR: Baseline systolic blood pressure (SBP) < 130, 130-160 (reference group), and > 160 mm Hg. OUTCOMES: Participants were followed up for 5 years to examine rates of mortality (primary outcome) and cardiovascular disease hospitalizations (secondary outcome). RESULTS: At baseline, 3,099 participants (38.5%) had SBP < 130 mm Hg, 3,772 (46.9%) had SBP of 131-160 mm Hg, and 1,171 (14.6%) had SBP >160 mm Hg. A total of 3,734 (46.4%) died and 2,881 (35.8%) were hospitalized. Adjusted HRs for mortality in the groups with SBP < 130 and > 160 mm Hg were 1.22 (95% CI, 1.11-1.34) and 1.06 (95% CI, 0.93-1.22), respectively. Adjusted HRs for cardiovascular hospitalization in these groups were 1.10 (95% CI, 0.99-1.23) and 1.26 (95% CI, 1.09-1.45), respectively. LIMITATIONS: Although causality should not be inferred from this retrospective analysis, results from this study can generate hypotheses for future randomized controlled trials to investigate the relationship between blood pressure and outcomes in older patients with CKD. CONCLUSIONS: Our study suggests that lower baseline SBP (≤ 130 mm Hg) may predict poorer outcomes in terms of both mortality and cardiovascular hospitalizations in older adults with CKD. Conversely, higher baseline SBP (> 160 mm Hg) may predict increased risk of cardiovascular hospitalizations, but does not predict mortality. Clinical trials are required to test this hypothesis.

Outcomes predicted by phosphorous in chronic kidney disease: a retrospective CKD-inception cohort study.

BACKGROUND: The impact of secondary hyperparathyroidism on morbidity and mortality among patients with chronic kidney disease (CKD) is unclear. METHODS: We conducted a retrospective cohort study to investigate the relationship between CKD and serum phosphorous. Through clinical databases at a large health maintenance organization, we identified a dynamic CKD inception cohort between 1997 and 2004, with stage 3-5 kidney disease with subsequent phosphorous measurement; the patients were followed up for up to 5 years for outcomes of mortality, cardiovascular mortality, cardiovascular hospitalizations and renal replacement therapy (RRT; dialysis or transplant). Survival analysis with time-varying covariables for phosphorous and renal function estimated the relationship between phosphorous level and outcomes, adjusting for potential confounding variables. RESULTS: A total of 930 patients with complete data were included in our analysis; they had a higher disease burden than excluded patients. Phosphorous did not predict overall or cardiovascular mortality, or cardiovascular hospitalizations. The rate of RRT increased significantly with the level of phosphorous, even when controlling for renal function. CONCLUSIONS: Contrary to some previous reports, we did not find evidence of increased mortality with phosphorous, but did find that increased levels of phosphorous are related to excess rates of RRT. Our work does not suggest that controlling phosphorous will lower the risk of RRT; our work motivates randomized controlled trials to investigate the clinical value of such interventions.

Predicting the risk of hyperkalemia in patients with chronic kidney disease starting lisinopril.

PURPOSE: Angiotensin-converting enzyme (ACE) inhibitors are recommended for patients with chronic kidney disease (CKD) because they slow disease progression. But physicians' concerns about the risk of hyperkalemia (elevated serum potassium level), a potentially fatal adverse effect, may limit optimal management with ACE-inhibitors. We synthesized known predictors of hyperkalemia into a prognostic risk score to predict the risk of hyperkalemia. METHODS: We assembled a retrospective cohort of adult patients with possible CKD (at least one estimated glomerular filtration rate (eGFR) value less than 60 ml/min/1.73 m(2)) who started an ACE-inhibitor (i.e., incident users) between 1998 and 2006 at a health maintenance organization. We followed patients for hyperkalemia: (1) potassium value >5.5 mmol/L; or (2) diagnosis code for hyperkalemia. Cox regression synthesized a priori predictors recorded in the electronic medical record into a risk score. RESULTS: We followed 5171 patients and 145 experienced hyperkalemia, a 90-day risk of 2.8%. Predictors included: age, eGFR, diabetes, heart failure, potassium supplements, potassium-sparing diuretics, and a high dose for the ACE-inhibitor (lisinopril). The risk score separated high-risk patients (top quintile, observed risk of 6.9%) from low-risk patients (bottom quintile, observed risk of 0.7%). Predicted and observed risks agreed within 1% for each quintile. The risk increased gradually in relation to declining eGFR with no apparent threshold for contraindicating ACE-inhibitors. CONCLUSIONS: The risk score separated high-risk patients (who may need more intensive laboratory monitoring) from low-risk patients. The risk score should be validated in other populations before it is ready for use in clinical practice.

A Quality Improvement Initiative Targeting Chronic Kidney Disease Metrics Through Increased Urinary Albumin Testing.

INTRODUCTION: Achievement of quality metrics in chronic kidney disease (CKD), specifically urinary albumin testing and angiotensin-converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) use, remained lower in Kaiser Permanente Northwest compared with other Kaiser Permanente regions. We were interested if more frequent testing of urine albumin (ACR) improved CKD quality metrics. METHODS: We implemented a quality improvement project automating ACR testing using an informatics tool in patients with stage 3 CKD linked to an electronic health record (EHR) alert recommending ACEi or ARB initiation in patients with renal indication. RESULTS: At 1 and 2 years after implementation of ACR testing, ACR testing increased from 26.9% prior to implementation to 83% at 1 year and 77% at 2 year after implementation (p < 0.001). However, ACEi or ARB use did not increase significantly (65.8% vs 65.7% vs 66.4%, p = 0.54). There was also no significant change in other quality metrics, including diabetes control, hypertension control, and comanagement of higher-risk CKD patients. DISCUSSION AND CONCLUSION: In patients with stage 3 CKD, increased ACR testing via automated testing linked with EHR alert did not result in an improvement in CKD quality metrics.

Effect of anaemia on mortality, cardiovascular hospitalizations and end-stage renal disease among patients with chronic kidney disease.

OBJECTIVE: To determine whether an independent association exists between anaemia and chronic kidney disease (CKD) outcomes in a quasi-incidence cohort when patients' most recent laboratory values are considered. METHODS: We conducted a dynamic, retrospective cohort study among patients with incident CKD in a large health maintenance organization administrative data set. CKD was defined by two estimated glomerular filtration rates (eGFR). We measured the absolute rates for all-cause mortality, cardiovascular hospitalizations and end-stage renal disease. RESULTS: Our completed cases Cox regression model followed 5885 patients with both CKD and haemoglobin measures. For patients with the most severe anaemia (haemoglobin <10.5 g/dL), we estimated an increased rate of mortality (hazard ratio (HR)=5.27, CI 4.37-6.35), cardiovascular hospitalizations (HR=2.18, CI 1.76-2.70) and end-stage renal disease (HR=5.46, CI 3.38-8.82) when compared with patients who were not anaemic; the HR reflect time-varying haemoglobins and eGFR. CONCLUSION: Anaemia is a predictor of excess mortality, excess cardiovascular hospitalizations and excess end-stage renal disease even when the progression of CKD is considered by controlling for time-varying eGFR values.

Adherence to K/DOQI bone metabolism guidelines.

OBJECTIVE: Guidelines for the treatment of patients with chronic kidney disease recommend laboratory testing of markers of bone metabolism, including intact parathyroid hormone, calcium, and phosphorus. The authors sought to evaluate the concordance of contemporary clinical practice with treatment recommendations. Trends were evaluated (2002 to 2005) in testing for bone metabolism in patients with chronic kidney disease, and the relation between bone metabolism markers, severity of chronic kidney disease, and cardiovascular hospitalizations were examined. DESIGN: Retrospective cohort. SETTING: Large United States health-maintenance organization. PATIENTS: Chronic kidney disease. RESULTS: Little variation was found in testing rates over time. Testing frequency was positively correlated with severity of kidney disease, referral to nephrology, and test type (annual testing was most likely for intact parathyroid hormone, and least likely for calcium). Patients with higher intact parathyroid hormone values had a greater risk of cardiovascular-related hospitalization; after adjusting for potential confounders, those with an intact parathyroid hormone value of 200 and greater had a relative risk of 2.16 (95% confidence interval, 1.09 to 4.29). CONCLUSIONS: This study supports the hypothesized association between disorders of bone metabolism and cardiovascular disease, but it does not address whether increased testing for disorders of bone metabolism will improve outcomes for patients with chronic kidney disease. Nor does our analysis imply that controlling parathyroid hormone will prevent cardiovascular hospitalizations. Future studies should more fully explore those critical clinical questions.

Predicting the risk of dialysis and transplant among patients with CKD: a retrospective cohort study.

BACKGROUND: Providers need a reliable way to identify patients with chronic kidney disease (CKD) at the highest risk of progression to end-stage renal disease so they can intervene to slow progression and refer patients to nephrology for comanagement. We developed a risk score to predict the 5-year risk of renal replacement therapy (RRT) in patients with stage 3 or 4 CKD. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: Participants were members of a health maintenance organization and met Kidney Disease Outcomes Quality Initiative criteria for stage 3 or 4 CKD during 1999 or 2000: two estimated glomerular filtration rate values of 15 to 59 mL/min/1.73 m(2). PREDICTOR: Characteristics collected during routine clinical practice. OUTCOMES & MEASUREMENTS: We ascertained the onset of RRT (dialysis or kidney transplantation) using the health maintenance organization databases. Cox regression predicted patient risk of RRT and generated a risk scoring system. RESULTS: 9,782 patients experienced a 3.3% five-year progression to RRT (95% confidence interval, 2.9 to 3.7). Using 6 characteristics (age, sex, estimated glomerular filtration rate, diabetes, anemia, and hypertension), the risk score discriminated the highest risk patients effectively: 19.0% of patients in the highest risk quintile experienced progression, and 0.2% of patients in the lowest risk quintile experienced progression. The c statistic also showed effective discrimination: 0.89 on a scale of 0.5 to 1.0. Predicted and observed risks agreed within 1.0%--effective calibration. We present a range of predicted risk cutoff values from 1% to 20% and their test properties for decision makers' consideration. LIMITATIONS: Characteristics were measured without a protocol. CONCLUSIONS: The risk score can help providers identify patients with CKD at the highest risk of progression to improve referral to nephrology for comanagement. A separate risk score for mortality also is needed.

Association of Proteinuria with Central Venous Catheter Use at Initial Hemodialysis.

CONTEXT: Central venous catheter (CVC) use is associated with increased mortality and complications in hemodialysis recipients. Although prevalent CVC use has decreased, incident use remains high. OBJECTIVE: To examine characteristics associated with CVC use at initial dialysis, specifically looking at proteinuria as a predictor of interest. DESIGN: Retrospective cohort of 918 hemodialysis recipients from Kaiser Permanente Northwest who started hemodialysis from January 1, 2004, to January 1, 2014. MAIN OUTCOME MEASURES: Multivariable logistic regression was used to examine an association of proteinuria with the primary outcome of CVC use. RESULTS: More than one-third (36%) of patients in our cohort started hemodialysis with an arteriovenous fistula, and 64% started with a CVC. Proteinuria was associated with starting hemodialysis with a CVC (likelihood ratio test, p < 0.001) after adjustment for age, peripheral vascular disease, congestive heart failure, diabetes, sex, race, and length of predialysis care. However, on pairwise comparison, only patients with midgrade proteinuria (0.5-3.5 g) had lower odds of starting hemodialysis with a CVC (odds ratio = 0.39, 95% confidence interval = 0.24-0.65). CONCLUSION: Proteinuria was associated with use of CVC at initial hemodialysis. However, a graded association did not exist, and only patients with midgrade proteinuria had significantly lower odds of CVC use. Our findings suggest that proteinuria is an explanatory finding for CVC use but may not have pragmatic value for decision making. Patients with lower levels of proteinuria may have a higher risk of starting dialysis with a CVC.

Predicting renal replacement therapy and mortality in CKD.

BACKGROUND: Prognostic risk scores can help clinicians intervene on higher risk patients and counsel them. Our objective is to identify characteristics that predict the rate of progression to renal replacement therapy (RRT) and evaluate how those characteristics predict mortality and a composite end point (RRT and mortality). STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: We conducted the study at Kaiser Permanente Northwest, a health maintenance organization. We followed up members with an estimated glomerular filtration rate (eGFR) that indicated chronic kidney disease (2 eGFRs < 60 mL/min/1.73 m(2) [<1.0 mL/s/1.73 m(2)] at least 90 days apart). PREDICTORS: We measured baseline clinical characteristics between January 1997 and June 2000 by using electronic medical records and patients' histories of hospitalization. OUTCOMES & MEASUREMENTS: We calculated adjusted hazard ratios and concordance statistics for progression to RRT, mortality, and the composite by using Cox regression. RESULTS: Patients (n = 6,541) were followed up for up to 5 years. We observed 1.6 progressions to RRT/100 person-years and 11.4 deaths/100 person-years. The 6 characteristics of age, sex, eGFR, diabetes, hypertension, and anemia predicted RRT effectively (c statistic, 0.91). However, hypertension and age predicted in the opposite direction for mortality and its composite end point. The c statistic decreased: mortality (0.70), mortality and RRT (0.71). LIMITATIONS: Characteristics were measured without a protocol; extensive missing data prevented the evaluation of known risk factors (eg, proteinuria). CONCLUSIONS: Predicting RRT effectively requires a separate risk score. Predicting the composite end point would favor characteristics that predict mortality because it is 7 times as common as RRT.