Arsh K. Jain

Global Trends in Rates of Peritoneal Dialysis

Although there is a perception that the use of peritoneal dialysis is declining worldwide, compilations of global data are unavailable to test this hypothesis. We assessed longitudinal trends in the use of peritoneal dialysis from 1997 to 2008 in 130 countries. The preferred data sources were renal registries, followed by nephrology societies, health ministries, academic centers, national experts, and industry affiliates. In 2008, there were approximately 196,000 peritoneal dialysis patients worldwide, representing 11% of the dialysis population. In total, 59% were treated in developing countries and 41% in developed countries. Over 12 years, the number of peritoneal dialysis patients increased in developing countries by 24.9 patients per million population and in developed countries by 21.8 per million population. The proportion of all dialysis patients treated with peritoneal dialysis did not change in developing countries but significantly declined in developed countries by 5.3%. The use of automated peritoneal dialysis increased by 14.5% in developing countries and by 30.3% in developed countries. In summary, the number of patients treated with peritoneal dialysis rose worldwide from 1997 to 2008, with a 2.5-fold increase in the prevalence of peritoneal dialysis patients in developing countries. The proportion of all dialysis patients treated with this modality continues to decline in developed countries.

Nephrology Visits and Health Care Resource Use Before and After Reporting Estimated Glomerular Filtration Rate

CONTEXT Laboratory reporting of estimated glomerular filtration rate (GFR) has been widely implemented, with limited evaluation. OBJECTIVE To examine trends in nephrologist visits and health care resource use before and after estimated GFR reporting. DESIGN, SETTING, AND PATIENTS Community-based cohort study (N = 1,135,968) with time-series analysis. Participants were identified from a laboratory registry in Alberta, Canada, and followed up from May 15, 2003, to March 14, 2007 (with estimated GFR reporting implemented October 15, 2004). MAIN OUTCOME MEASURE Nephrologist visits and patient management. RESULTS Following estimated GFR reporting, the rate of first outpatient visits to a nephrologist for patients with chronic kidney disease (CKD; estimated GFR <60 mL/min/1.73 m(2)) increased by 17.5 (95% confidence interval [CI], 16.5-18.6) visits per 10,000 CKD patients per month, corresponding to a relative increase from baseline of 68.4% (95% CI, 65.7%-71.2%). There was no association between estimated GFR reporting and rate of first nephrologist visit among patients without CKD. Among patients with an estimated GFR of less than 30 mL/min/1.73 m(2), the rate of first nephrologist visits increased by 134.4 (95% CI, 60.0-208.7) visits per 10,000 patients per month. This increase was predominantly seen in women, patients aged 46 to 65 years as well as those aged 86 years or older, and those with hypertension, diabetes, and comorbidity. Reporting of estimated GFR was not associated with increased rates of internal medicine or general practitioner visits or increased use of angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers among patients with CKD and proteinuria or the subgroup limited to patients with diabetes. CONCLUSIONS Reporting of estimated GFR was associated with an increase in first nephrologist visits, particularly among patients with more severe kidney dysfunction, women, middle-aged and very elderly patients, and those with comorbidities. Any effect on outcomes remains to be shown.

Statin Use Associates with a Lower Incidence of Acute Kidney Injury after Major Elective Surgery

Statins abrogate ischemic renal injury in animal studies but whether they are renoprotective in humans is unknown. We conducted a population-based retrospective cohort study that included 213,347 older patients who underwent major elective surgery in the province of Ontario, Canada from 1995 to 2008. During the first 14 postoperative days, 1.9% (4020 patients), developed acute kidney injury and 0.5% (1173 patients), required acute dialysis. The 30-day mortality rate was 2.8% (5974 patients). Prior to surgery, 32% of patients were taking a statin. After statistical adjustment for patient and surgical characteristics, statin use associated with 16% lower odds of acute kidney injury (OR, 0.84; 95% CI, 0.79 to 0.90), 17% lower odds of acute dialysis (OR, 0.83; 95% CI, 0.72 to 0.95), and 21% lower odds of mortality (OR, 0.79; 95% CI, 0.74 to 0.85). Propensity score matching produced similar results. These data suggest that statins may protect against renal complications after major elective surgery and reduce perioperative mortality.

The Secret of Immortal Time Bias in Epidemiologic Studies

In the March 2007 issue of JASN , Hemmelgarn et al. [1][1] reported a 50% reduction in the risk for all-cause mortality for patients who had chronic kidney disease (CKD) and attended multidisciplinary care (MDC) clinics compared with those who received usual care. Their survival curves showed a

When laboratories report estimated glomerular filtration rates in addition to serum creatinines, nephrology consults increase

Serum creatinine alone can be difficult to interpret as a measure of kidney function such that chronic kidney disease might be under-recognized in the general population. In the province of Ontario, Canada, all outpatient laboratories now report estimated glomerular filtration rate (eGFR) in addition to serum creatinine. To determine the impact of this reporting on clinical practice, we linked health administrative data for more than 8 million adults of age 25 years or older over an almost 10-year period and conducted a population-based intervention analysis with seasonal time-series modeling to determine overall trends in the number and type of patients seen by nephrologists. Compared to the period when only serum creatinines were reported, the number of patients seen in consultation by nephrologists increased after eGFR reporting by an average of 24% (an absolute increase of 2.9 consults per 100,000 adults), an increase of about 23 consults per nephrologist per year. The greatest increases were seen in women (39% increase) and those 80 years of age and older (58% increase). Our study found that eGFR reporting was associated with a sudden increase in the number of nephrology consults. However, it remains to be seen whether the routine reporting of eGFR results in improved treatment and outcomes for those with chronic kidney disease.

Secular trends in acute dialysis after elective major surgery — 1995 to 2009

Background: Acute kidney injury is a serious complication of elective major surgery. Acute dialysis is used to support life in the most severe cases. We examined whether rates and outcomes of acute dialysis after elective major surgery have changed over time. Methods: We used data from Ontario’s universal health care databases to study all consecutive patients who had elective major surgery at 118 hospitals between 1995 and 2009. Our primary outcomes were acute dialysis within 14 days of surgery, death within 90 days of surgery and chronic dialysis for patients who did not recover kidney function. Results: A total of 552 672 patients underwent elective major surgery during the study period, 2231 of whom received acute dialysis. The incidence of acute dialysis increased steadily from 0.2% in 1995 (95% confidence interval [CI] 0.15–0.2) to 0.6% in 2009 (95% CI 0.6–0.7). This increase was primarily in cardiac and vascular surgeries. Among patients who received acute dialysis, 937 died within 90 days of surgery (42.0%, 95% CI 40.0–44.1), with no change in 90-day survival over time. Among the 1294 patients who received acute dialysis and survived beyond 90 days, 352 required chronic dialysis (27.2%, 95% CI 24.8–29.7), with no change over time. Interpretation: The use of acute dialysis after cardiac and vascular surgery has increased substantially since 1995. Studies focusing on interventions to better prevent and treat perioperative acute kidney injury are needed.

Validity of the International Classification of Diseases, Tenth Revision code for acute kidney injury in elderly patients at presentation to the emergency department and at hospital admission

Objective To evaluate the validity of the International Classification of Diseases, Tenth Revision (ICD-10) code N17x for acute kidney injury (AKI) in elderly patients in two settings: at presentation to the emergency department and at hospital admission. Design A population-based retrospective validation study. Setting Southwestern Ontario, Canada, from 2003 to 2010. Participants Elderly patients with serum creatinine measurements at presentation to the emergency department (n=36 049) or hospital admission (n=38 566). The baseline serum creatinine measurement was a median of 102 and 39 days prior to presentation to the emergency department and hospital admission, respectively. Main outcome measures Sensitivity, specificity and positive and negative predictive values of ICD-10 diagnostic coding algorithms for AKI using a reference standard based on changes in serum creatinine from the baseline value. Median changes in serum creatinine of patients who were code positive and code negative for AKI. Results The sensitivity of the best-performing coding algorithm for AKI (defined as a ≥2-fold increase in serum creatinine concentration) was 37.4% (95% CI 32.1% to 43.1%) at presentation to the emergency department and 61.6% (95% CI 57.5% to 65.5%) at hospital admission. The specificity was greater than 95% in both settings. In patients who were code positive for AKI, the median (IQR) increase in serum creatinine from the baseline was 133 (62 to 288) µmol/l at presentation to the emergency department and 98 (43 to 200) µmol/l at hospital admission. In those who were code negative, the increase in serum creatinine was 2 (−8 to 14) and 6 (−4 to 20) µmol/l, respectively. Conclusions The presence or absence of ICD-10 code N17× differentiates two groups of patients with distinct changes in serum creatinine at the time of a hospital encounter. However, the code underestimates the true incidence of AKI due to a limited sensitivity.

Impact of Estimated GFR Reporting on Patients, Clinicians, and Health-Care Systems: A Systematic Review

BACKGROUND Many laboratories now report estimated glomerular filtration rate (eGFR) when a serum creatinine measurement is ordered. A summary of the impact of eGFR reporting in health care systems around the world for which it has been adopted is lacking. STUDY DESIGN Systematic review of MEDLINE, EMBASE, other major databases, and conference proceedings of major nephrology meetings. SETTING & POPULATION Any health care system in which eGFR reporting was introduced. SELECTION CRITERIA FOR STUDIES Published studies or abstracts reporting patient, clinician, or health system outcomes of eGFR reporting. INTERVENTION eGFR reporting. OUTCOMES Volume of referrals or consults seen by nephrologists, changes in characteristics of patients who were seen, and prescription rates of kidney-related medications. RESULTS 22 studies (10 full text and 12 conference abstracts) were identified in 2004-2010 from 5 countries. Nephrologist referrals and consultations increased after eGFR reporting, ranging from 13%-270%. The greatest increases in referrals were seen for the elderly, females, and those with stage 3 or higher chronic kidney disease (eGFR <60 mL/min/1.73 m(2)). Change in renin-angiotensin-aldosterone system-blocking drug use ranged from increases of 0%-6%. LIMITATIONS Studies were highly variable in definition of outcomes. Reports were not available for many health care systems in which eGFR reporting was implemented. CONCLUSIONS eGFR reporting has been associated with greater identification of patients with decreased kidney function in most health care systems that have reported its impact.

Use of Clinical Decision Support Systems for Kidney-Related Drug Prescribing: A Systematic Review

BACKGROUND Clinical decision support systems (CDSSs) have the potential to improve kidney-related drug prescribing by supporting the appropriate initiation, modification, monitoring, or discontinuation of drug therapy. STUDY DESIGN Systematic review. We identified studies by searching multiple bibliographic databases (eg, MEDLINE and EMBASE), conference proceedings, and reference lists of all included studies. SETTING & POPULATION CDSSs used in hospital or outpatient settings for acute kidney injury and chronic kidney disease, including end-stage renal disease (chronic dialysis patients or transplant recipients). SELECTION CRITERIA FOR STUDIES Studies prospectively using CDSSs to aid in kidney-related drug prescribing. INTERVENTION Computerized or manual CDSSs. OUTCOMES Clinician prescribing and patient-important outcomes as reported by primary study investigators. CDSS characteristics, such as whether the system was computerized, and system setting. RESULTS We identified 32 studies. In 17 studies, CDSSs were computerized, and in 15 studies, they were manual pharmacist-based systems. Systems intervened by prompting for drug dosing adjustments in relation to the level of decreased kidney function (25 studies) or in response to serum drug concentrations or a clinical parameter (7 studies). They were used most in academic hospital settings. For computerized CDSSs, clinician prescribing outcomes (eg, frequency of appropriate dosing) were considered in 11 studies, with all 11 reporting statistically significant improvements. Similarly, manual CDSSs that incorporated clinician prescribing outcomes showed statistically significant improvements in 6 of 8 studies. Patient-important outcomes (eg, adverse drug events) were considered in 7 studies of computerized CDSSs, with statistically significant improvements in 2 studies. For manual CDSSs, 6 studies measured patient-important outcomes and 5 reported statistically significant improvements. Cost-savings also were reported, mostly for manual CDSSs. LIMITATIONS Studies were heterogeneous in design and often limited by the evaluation method used. Benefits of CDSSs may be reported selectively in this literature. CONCLUSION CDSSs are available for many dimensions of kidney-related drug prescribing, and results are promising. Additional high-quality evaluations will guide their optimal use.

Dipstick Proteinuria as a Screening Strategy to Identify Rapid Renal Decline

Rapid kidney function decline (RKFD) predicts cardiovascular morbidity and mortality, but serial assessment of estimated GFR (eGFR) is not cost-effective for the general population. Here, we evaluated the predictive value of albuminuria and three thresholds of dipstick proteinuria to identify RKFD in 2,574 participants in a community-based prospective cohort study with a median of 7 years follow-up. Median change in eGFR was -0.78 ml/min per 1.73 m(2) per year; with 8.5% experiencing RKFD, defined as a >5% annual eGFR decline from baseline. Of those with RKFD, 65% advanced to a new CKD stage compared with 19% of those without RKFD. Dipstick protein ≥ 1 g/L was a stronger predictor of RKFD than albuminuria. Overall, 2.5% screened positive for dipstick protein ≥ 1 g/L at baseline; one of every 2.6 patients would have RKFD if all were followed with serial eGFR measurement. Overall, the screening strategy correctly identified progression status for 90.8% of patients, mislabeled 1.5% as RKFD, and missed 7.7% with eventual RKFD. Among those with risk factors (cardiovascular disease, age >60, diabetes, or hypertension), the probability of identifying RKFD from serial eGFR measurements increased from 13 to 44% after incorporating dipstick protein (≥ 1 g/L threshold). In summary, inexpensive screening with urine dipstick should allow primary care physicians to follow fewer patients with serial eGFR assessment but still identify those with rapid decline of kidney function.