Summary Background Low values of estimated glomerular filtration rate (eGFR) predispose to acute kidney injury, and proteinuria is a marker of kidney disease. We aimed to investigate how eGFR and ...proteinuria jointly modified the risks of acute kidney injury and subsequent adverse clinical outcomes. Methods We did a cohort study of 920 985 adults residing in Alberta, Canada, between 2002 and 2007. Participants not needing chronic dialysis at baseline and with at least one outpatient measurement of both serum creatinine concentration and proteinuria (urine dipstick or albumin-creatinine ratio) were included. We assessed hospital admission with acute kidney injury with validated administrative codes; other outcomes were all-cause mortality and a composite renal outcome of end-stage renal disease or doubling of serum creatinine concentration. Findings During median follow-up of 35 months (range 0–59 months), 6520 (0·7%) participants were admitted with acute kidney injury. In those with eGFR 60 mL/min per 1·73 m2 or greater, the adjusted risk of admission with this disorder was about 4 times higher in those with heavy proteinuria measured by dipstick (rate ratio 4·4 vs no proteinuria, 95% CI 3·7–5·2). The adjusted rates of admission with acute kidney injury and kidney injury needing dialysis remained high in participants with heavy dipstick proteinuria for all values of eGFR. The adjusted rates of death and the composite renal outcome were also high in participants admitted with acute kidney injury, although the rise associated with this injury was attenuated in those with low baseline eGFR and heavy proteinuria. Interpretation These findings suggest that information on proteinuria and eGFR should be used together when identifying people at risk of acute kidney injury, and that an episode of acute kidney injury provides further long-term prognostic information in addition to eGFR and proteinuria. Funding The study was funded by an interdisciplinary team grant from Alberta Heritage Foundation for Medical Research.
Clinical experience suggests that there are substantial differences in patient complexity across medical specialties, but empirical data are lacking.
To compare the complexity of patients seen by ...different types of physician in a universal health care system.
Population-based retrospective cohort study of 2 597 127 residents of the Canadian province of Alberta aged 18 years and older with at least 1 physician visit between April 1, 2014 and March 31, 2015. Data were analyzed in September 2018.
Type of physician seeing each patient (family physician, general internist, or 11 types of medical subspecialist) assessed as non-mutually exclusive categories.
Nine markers of patient complexity (number of comorbidities, presence of mental illness, number of types of physicians involved in each patient's care, number of physicians involved in each patient's care, number of prescribed medications, number of emergency department visits, rate of death, rate of hospitalization, rate of placement in a long-term care facility).
Among the 2 597 127 participants, the median (interquartile range) age was 46 (32-59) years and 54.1% were female. Over 1 year of follow-up, 21 792 patients (0.8%) died, the median (range) number of days spent in the hospital was 0 (0-365), 8.1% of patients had at least 1 hospitalization, and the median (interquartile range) number of prescribed medications was 3 (1-7). When the complexity markers were considered individually, patients seen by nephrologists had the highest mean number of comorbidities (4.2; 95% CI, 4.2-4.3 vs lowest 1.1; 95% CI, 1.0-1.1), highest mean number of prescribed medications (14.2; 95% CI, 14.2-14.3 vs lowest 4.9; 95% CI, 4.9-4.9), highest rate of death (6.6%; 95% CI, 6.3%-6.9% vs lowest 0.1%; 95% CI, <0.1%-0.2%), and highest rate of placement in a long-term care facility (2.0%; 95% CI, 1.8%-2.2% vs lowest <0.1%; 95% CI, <0.1%-0.1%). Patients seen by infectious disease specialists had the highest complexity as assessed by the other 5 markers: rate of a mental health condition (29%; 95% CI, 28%-29% vs lowest 14%; 95% CI, 14%-14%), mean number of physician types (5.5; 95% CI, 5.5-5.6 vs lowest 2.1; 95% CI, 2.1-2.1), mean number of physicians (13.0; 95% CI, 12.9-13.1 vs lowest 3.8; 95% CI, 3.8-3.8), mean days in hospital (15.0; 95% CI, 14.9-15.0 vs lowest 0.4; 95% CI, 0.4-0.4), and mean emergency department visits (2.6; 95% CI, 2.6-2.6 vs lowest 0.5; 95% CI, 0.5-0.5). When types of physician were ranked according to patient complexity across all 9 markers, the order from most to least complex was nephrologist, infectious disease specialist, neurologist, respirologist, hematologist, rheumatologist, gastroenterologist, cardiologist, general internist, endocrinologist, allergist/immunologist, dermatologist, and family physician.
Substantial differences were found in 9 different markers of patient complexity across different types of physician, including medical subspecialists, general internists, and family physicians. These findings have implications for medical education and health policy.
Acute kidney injury (AKI) is associated with early mortality after percutaneous coronary revascularization procedures, but its prognostic relevance to long-term clinical outcomes remains ...controversial.
We conducted a retrospective study of 14782 adults who received coronary angiography in the province of Alberta, Canada, between 2004 and 2006. AKI was identified on the basis of changes in serum creatinine concentration within 7 days of the procedure according to AKI Network criteria. The associations between AKI and long-term outcomes, including mortality, end-stage renal disease, and cardiovascular and renal hospitalizations, were studied with the use of Cox regression of multiple failure times. The adjusted risk of death increased with increasing severity of AKI; compared with no AKI, the adjusted hazard ratio for death was 2.00 (95% confidence interval, 1.69 to 2.36) with stage 1 AKI and 3.72 (95% confidence interval, 2.92 to 4.76) with stage 2 or 3 AKI. The adjusted risk of end-stage renal disease requiring renal replacement therapy also increased according to the severity of AKI (hazard ratio, 4.15 95% confidence interval, 2.32 to 7.42 and 11.74 95% confidence interval, 6.38 to 21.59, respectively), as did the risks of subsequent hospitalizations for heart failure and acute renal failure.
These findings inform the controversy surrounding AKI after angiography, demonstrating that it is a significant risk factor for long-term mortality, end-stage renal disease, and hospitalization for cardiovascular and renal events after coronary angiography.
Although obstructive sleep apnea (OSA) is more common in patients with kidney disease, whether nocturnal hypoxia affects kidney function is unknown.
We studied all adult subjects referred for ...diagnostic testing of sleep apnea between July 2005 and December 31 2007 who had serial measurement of their kidney function. Nocturnal hypoxia was defined as oxygen saturation (SaO2) below 90% for ≥12% of the nocturnal monitoring time. The primary outcome, accelerated loss of kidney function, was defined as a decline in estimated glomerular filtration rate (eGFR) ≥4 ml/min/1.73 m(2) per year.
858 participants were included and followed for a mean study period of 2.1 years. Overall 374 (44%) had nocturnal hypoxia, and 49 (5.7%) had accelerated loss of kidney function. Compared to controls without hypoxia, patients with nocturnal hypoxia had a significant increase in the adjusted risk of accelerated kidney function loss (odds ratio (OR) 2.89, 95% confidence interval CI 1.25, 6.67).
Nocturnal hypoxia was independently associated with an increased risk of accelerated kidney function loss. Further studies are required to determine whether treatment and correction of nocturnal hypoxia reduces loss of kidney function.
Abstract
Dermatomyositis is a rare disease characterized by progressive muscle weakness and skin rashes. Estimates of incidence and prevalence are fundamental measures in epidemiology, but few ...studies have been conducted on dermatomyositis. To address this knowledge gap, we conducted a population-based study to determine the contemporary incidence (between 2013 and 2019) and prevalence (2019) of adults living with dermatomyositis using administrative health data in Alberta, Canada. We also described disease-related medication use, as there are very few approved medications for the treatment of dermatomyositis, and no Canadian therapeutic guidelines. The average age- and sex-standardized annual incidence of dermatomyositis was 2.8–3.0 cases per 100,000 adults, and prevalence was 28.6 cases per 100,000 adults, which is greater than reported in other cohorts. Dermatomyositis-related medication use decreased from 73% in the first year to 46% in the eighth year after diagnosis. Glucocorticoids were the most commonly used drug class, often taken concurrently with various immunomodulatory agents; this medication use aligns with empirically-based recommendations and the few therapeutic guidelines for dermatomyositis. Considering that Alberta may have one of the highest rates of dermatomyositis among adults, further research on the burden of disease is warranted for planning within the health care system.
Higher levels of red cell distribution width (RDW) are associated with adverse outcomes, especially in selected cohorts with or at risk for chronic disease. Whether higher RDW or the related ...parameter standard deviation of the red blood cell distribution (SD-RBC) can predict a broader range of outcomes in the general population is unknown.
To evaluate the association of RDW and SD-RBC with the risk of adverse outcomes in people from the general population.
Population-based retrospective cohort study.
Health care system in a Canadian province (Alberta).
All 3,156,863 adults living in Alberta, Canada with at least one measure of RDW and SD-RBC between 2003 and 2016. Data were analyzed in September 2018.
RDW and SD-RBC, classified into percentiles (<1, 1-5, 5-25, 25-75, 75-95, 95-99, >99).
All-cause death, first myocardial infarction, first stroke or transient ischemic attack, placement into long-term care (LTC), progression to renal replacement therapy (initiation of chronic dialysis or pre-emptive kidney transplantation), incident solid malignancy, and first hospitalization during follow-up.
Over median follow-up of 6.8 years, 209,991 of 3,156,863 participants (6.7%) died. The risk of death increased with increasing RDW percentile. After adjustment, and compared to RDW in the 25th to 75th percentiles, the risk of death was lower for participants in the <25th percentiles but higher for participants in the 75th-95th percentiles (HR 1.42, 95% CI 1.40,1.43), the 95th-99th percentiles (HR 1.86, 95% CI 1.83,1.89) and the >99th percentile (HR 2.18, 95% CI 2.12,2.23). Similar results were observed for MI, stroke/TIA, incident cancer, hospitalization and LTC placement, but no association was found between RDW and ESRD. Findings were generally similar for SD-RBC, except that all associations tended to be stronger than for RDW, and both lower and higher values of SD-RBC were independently associated with ESRD.
RDW and SD-RBC may be useful as prognostic markers for people in the general population, especially for outcomes related to chronic illness. SD-RBC may be superior to RDW.
Chronic kidney disease (CKD) is associated with poor outcomes, perhaps due to a high burden of comorbidity. Most studies of CKD populations focus on concordant comorbidities, which cause CKD (such as ...hypertension and diabetes) or often accompany CKD (such as heart failure or coronary disease). Less is known about the burden of mental health conditions and discordant conditions (those not concordant but still clinically relevant, like dementia or cancer). Here we did a retrospective population-based cohort study of 530,771 adults with CKD residing in Alberta, Canada between 2003 and 2011. Validated algorithms were applied to data from the provincial health ministry to assess the presence/absence of 29 chronic comorbidities. Linkage between comorbidity burden and adverse clinical outcomes (mortality, hospitalization or myocardial infarction) was examined over median follow-up of 48 months. Comorbidities were classified into three categories: concordant, mental health/chronic pain, and discordant. The median number of comorbidities was 1 (range 0–15) but a substantial proportion of participants had 3 and more, or 5 and more comorbidities (25 and 7%, respectively). Concordant comorbidities were associated with excess risk of hospitalization, but so were discordant comorbidities and mental health conditions. Thus, discordant comorbidities and mental health conditions as well as concordant comorbidities are important independent drivers of the adverse outcomes associated with CKD.
Background: While historical rate of decline in kidney function is informally used by clinicians to estimate risk of future adverse clinical outcomes especially kidney failure, in people with type 2 ...diabetes the epidemiology and independent association of historical eGFR slope on risk is not well described. Objective: Determine the association of eGFR slope and risk of clinically important outcomes. Design Setting and Patients: Observational population-based cohort with type 2 diabetes in Alberta. Measurement and Methods: An Alberta population-based cohort with type 2 diabetes was assembled, characterized, and observed over 1 year (2018) for clinical outcomes of ESKD, first myocardial infarction, first stroke, heart failure, and disease-specific and all-cause hospitalization and mortality. Kidney function was defined using KDIGO criteria using the most recent eGFR and albuminuria measured in the preceding 18 months; annual eGFR slope utilized measurements in the 3 years prior and was parameterized using three methods (percentiles, and linear term with and without missingness indicator). Demographics, laboratory results, medications, and comorbid conditions using validated definitions were described. In addition to descriptive analysis, odds ratios from fully adjusted logistic models regressing outcomes on eGFR slope are reported; the marginal risk of clinical outcomes was also determined. Results: Among 336 376 participants with type 2 diabetes, the median annual eGFR slope was −0.41 mL/min/1.73 m 2 (IQR −1.67, 0.62). In fully adjusted models, eGFR slope was independently associated with many adverse clinical outcomes; among those with ≤10th percentile of slope (median −4.71 mL/min/1.73 m 2 ) the OR of kidney failure was 2.22 (95% CI 1.75, 2.82), new stroke 1.23 (1.08, 1.40), heart failure 1.42 (1.27, 1.59), MI 0.98 (0.77, 1.23) all-cause hospitalization 1.31 (1.26, 1.36) and all-cause mortality 1.56 (1.44, 1.68). For every −1 mL/min/1.73 m 2 in eGFR slope, the OR of outcomes ranged from 1.01 (0.98, 1.05 for new MI) to 1.09 (1.08, 1.10 for all-cause mortality); findings were significant for 10 of the 13 outcomes considered. Limitations: Causality cannot be established with this study design. Conclusions: These findings support consideration of the rate of eGFR decline in risk stratification and may inform clinicians and policymakers to optimize treatment and inform health care system planning.
Multimorbidity is common and associated with poor clinical outcomes and high health care costs. Administrative data are a promising tool for studying the epidemiology of multimorbidity. Our goal was ...to derive and apply a new scheme for using administrative data to identify the presence of chronic conditions and multimorbidity.
We identified validated algorithms that use ICD-9 CM/ICD-10 data to ascertain the presence or absence of 40 morbidities. Algorithms with both positive predictive value and sensitivity ≥70% were graded as "high validity"; those with positive predictive value ≥70% and sensitivity <70% were graded as "moderate validity". To show proof of concept, we applied identified algorithms with high to moderate validity to inpatient and outpatient claims and utilization data from 574,409 people residing in Edmonton, Canada during the 2008/2009 fiscal year.
Of the 40 morbidities, we identified 30 that could be identified with high to moderate validity. Approximately one quarter of participants had identified multimorbidity (2 or more conditions), one quarter had a single identified morbidity and the remaining participants were not identified as having any of the 30 morbidities.
We identified a panel of 30 chronic conditions that can be identified from administrative data using validated algorithms, facilitating the study and surveillance of multimorbidity. We encourage other groups to use this scheme, to facilitate comparisons between settings and jurisdictions.
PDF
