Arthur V. Iansavichus

Shift work and vascular events: systematic review and meta-analysis

Objective To synthesise the association of shift work with major vascular events as reported in the literature. Data sources Systematic searches of major bibliographic databases, contact with experts in the field, and review of reference lists of primary articles, review papers, and guidelines. Study selection Observational studies that reported risk ratios for vascular morbidity, vascular mortality, or all cause mortality in relation to shift work were included; control groups could be non-shift (“day”) workers or the general population. Data extraction Study quality was assessed with the Downs and Black scale for observational studies. The three primary outcomes were myocardial infarction, ischaemic stroke, and any coronary event. Heterogeneity was measured with the I2 statistic and computed random effects models. Results 34 studies in 2 011 935 people were identified. Shift work was associated with myocardial infarction (risk ratio 1.23, 95% confidence interval 1.15 to 1.31; I2=0) and ischaemic stroke (1.05, 1.01 to 1.09; I2=0). Coronary events were also increased (risk ratio 1.24, 1.10 to 1.39), albeit with significant heterogeneity across studies (I2=85%). Pooled risk ratios were significant for both unadjusted analyses and analyses adjusted for risk factors. All shift work schedules with the exception of evening shifts were associated with a statistically higher risk of coronary events. Shift work was not associated with increased rates of mortality (whether vascular cause specific or overall). Presence or absence of adjustment for smoking and socioeconomic status was not a source of heterogeneity in the primary studies. 6598 myocardial infarctions, 17 359 coronary events, and 1854 ischaemic strokes occurred. On the basis of the Canadian prevalence of shift work of 32.8%, the population attributable risks related to shift work were 7.0% for myocardial infarction, 7.3% for all coronary events, and 1.6% for ischaemic stroke. Conclusions Shift work is associated with vascular events, which may have implications for public policy and occupational medicine.

Pregnancy outcomes in women with chronic kidney disease: a systematic review.

BACKGROUND AND OBJECTIVES Pregnant women with chronic kidney disease (CKD) are at risk of adverse maternal and fetal outcomes. We conducted a systematic review of observational studies that described this risk. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS We searched several databases from their date of inception through June 2010 for eligible articles published in any language. We included any study that reported maternal or fetal outcomes in at least five pregnant women in each group with or without CKD. We excluded pregnant women with a history of transplantation or maintenance dialysis. RESULTS We identified 13 studies. Adverse maternal events including gestational hypertension, pre-eclampsia, eclampsia, and maternal mortality were reported in 12 studies. There were 312 adverse maternal events among 2682 pregnancies in women with CKD (weighted average of 11.5%) compared with 500 events in 26,149 pregnancies in normal healthy women (weighted average of 2%). One or more adverse fetal outcomes such as premature births, intrauterine growth restriction, small for gestational age, neonatal mortality, stillbirths, and low birth weight were reported in nine of the included studies. Overall, the risk of developing an adverse fetal outcome was at least two times higher among women with CKD compared with those without. CONCLUSIONS This review summarizes current available evidence to guide physicians in their decision-making, advice, and care for pregnant women with CKD. Additional studies are needed to better characterize the risks.

Validity of Administrative Database Coding for Kidney Disease: A Systematic Review

BACKGROUND Information in health administrative databases increasingly guides renal care and policy. STUDY DESIGN Systematic review of observational studies. SETTING & POPULATION Studies describing the validity of codes for acute kidney injury (AKI) and chronic kidney disease (CKD) in administrative databases operating in any jurisdiction. SELECTION CRITERIA After searching 13 medical databases, we included observational studies published from database inception though June 2009 that validated renal diagnostic and procedural codes for AKI or CKD against a reference standard. INDEX TESTS Renal diagnostic or procedural administrative data codes. REFERENCE TESTS Patient chart review, laboratory values, or data from a high-quality patient registry. RESULTS 25 studies of 13 databases in 4 countries were included. Validation of diagnostic and procedural codes for AKI was present in 9 studies, and validation for CKD was present in 19 studies. Sensitivity varied across studies and generally was poor (AKI median, 29%; range, 15%-81%; CKD median, 41%; range, 3%-88%). Positive predictive values often were reasonable, but results also were variable (AKI median, 67%; range, 15%-96%; CKD median, 78%; range, 29%-100%). Defining AKI and CKD by only the use of dialysis generally resulted in better code validity. The study characteristic associated with sensitivity in multivariable meta-regression was whether the reference standard used laboratory values (P < 0.001); sensitivity was 39% lower when laboratory values were used (95% CI, 23%-56%). LIMITATIONS Missing data in primary studies limited some of the analyses that could be done. CONCLUSIONS Administrative database analyses have utility, but must be conducted and interpreted judiciously to avoid bias arising from poor code validity.

Chronic kidney disease and postoperative mortality: A systematic review and meta-analysis

Whether renal dysfunction is an important factor in postoperative risk assessment has been difficult to prove. In an attempt to provide more compelling evidence, we conducted a systematic review comparing the risk of death and cardiac events in patients with and without chronic kidney disease who underwent elective noncardiac surgery. From electronic databases, web search engines, and bibliographies, 31 cohort studies were selected, evaluating postoperative outcomes in patients with chronic kidney disease. These patients had higher risks of postoperative death and cardiovascular events compared to those with preserved renal function. The pooled incidence of postoperative death was significantly less in those with preserved renal function than in those patients with chronic kidney disease. Meta-regression showed a graded relationship between disease severity and postoperative death. In adjusted analysis, chronic kidney disease had a similar strength of association with postoperative death as diabetes, stroke, and coronary disease. Our review identifies chronic kidney disease as an independent risk factor for postoperative death and cardiovascular events after elective, noncardiac surgery.

Retrieving Clinical Evidence: A Comparison of PubMed and Google Scholar for Quick Clinical Searches

Background Physicians frequently search PubMed for information to guide patient care. More recently, Google Scholar has gained popularity as another freely accessible bibliographic database. Objective To compare the performance of searches in PubMed and Google Scholar. Methods We surveyed nephrologists (kidney specialists) and provided each with a unique clinical question derived from 100 renal therapy systematic reviews. Each physician provided the search terms they would type into a bibliographic database to locate evidence to answer the clinical question. We executed each of these searches in PubMed and Google Scholar and compared results for the first 40 records retrieved (equivalent to 2 default search pages in PubMed). We evaluated the recall (proportion of relevant articles found) and precision (ratio of relevant to nonrelevant articles) of the searches performed in PubMed and Google Scholar. Primary studies included in the systematic reviews served as the reference standard for relevant articles. We further documented whether relevant articles were available as free full-texts. Results Compared with PubMed, the average search in Google Scholar retrieved twice as many relevant articles (PubMed: 11%; Google Scholar: 22%; P<.001). Precision was similar in both databases (PubMed: 6%; Google Scholar: 8%; P=.07). Google Scholar provided significantly greater access to free full-text publications (PubMed: 5%; Google Scholar: 14%; P<.001). Conclusions For quick clinical searches, Google Scholar returns twice as many relevant articles as PubMed and provides greater access to free full-text articles.

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.

Optimal Method of Coronary Revascularization in Patients Receiving Dialysis: Systematic Review

BACKGROUND AND OBJECTIVES Patients receiving dialysis have a high burden of cardiovascular disease. Some receive coronary artery revascularization but the optimal method is controversial. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS The authors reviewed any randomized controlled trial or cohort study of 10 or more patients receiving maintenance dialysis which compared coronary artery bypass graft (CABG) to percutaneous intervention (PCI) for revascularization of the coronary arteries. The primary outcomes were short-term (30 d or in-hospital) and long-term (at least 1 year) mortality. RESULTS Seventeen studies were found. There were no randomized trials: all were retrospective cohort studies from years 1977 to 2002. There were some baseline differences between the groups receiving CABG compared with those receiving PCI, and most studies did not consider results adjusted for such characteristics. Given the variability among studies and their methodological limitations, few definitive conclusions about the optimal method of revascularization could be drawn. In an exploratory meta-analysis, short-term mortality was higher after CABG compared to PCI. A substantial number of patients died over a subsequent 1 to 5 yr, with no difference in mortality after CABG compared to PCI. CONCLUSIONS Although decisions about the optimal method of coronary artery revascularization in dialysis patients are undertaken routinely, it was surprising to see how few data has been published in this regard. Additional research will help inform physician and patient decisions about coronary artery revascularization.

Filtering Medline for a clinical discipline: diagnostic test assessment framework

Objective To develop and test a Medline filter that allows clinicians to search for articles within a clinical discipline, rather than searching the entire Medline database. Design Diagnostic test assessment framework with development and validation phases. Setting Sample of 4657 articles published in 2006 from 40 journals. Reviews Each article was manually reviewed, and 19.8% contained information relevant to the discipline of nephrology. The performance of 1 155 087 unique renal filters was compared with the manual review. Main outcome measures Sensitivity, specificity, precision, and accuracy of each filter. Results The best renal filters combined two to 14 terms or phrases and included the terms “kidney” with multiple endings (that is, truncation), “renal replacement therapy”, “renal dialysis”, “kidney function tests”, “renal”, “nephr” truncated, “glomerul” truncated, and “proteinuria”. These filters achieved peak sensitivities of 97.8% and specificities of 98.5%. Performance of filters remained excellent in the validation phase. Conclusions Medline can be filtered for the discipline of nephrology in a reliable manner. Storing these high performance renal filters in PubMed could help clinicians with their everyday searching. Filters can also be developed for other clinical disciplines by using similar methods.

The risk of perioperative bleeding in patients with chronic kidney disease: a systematic review and meta-analysis.

Background: Worldwide, millions of patients with chronic kidney disease undergo surgery each year. Although chronic kidney disease increases the risk of bleeding in nonoperative settings, the risk of perioperative bleeding is less clear. We conducted a systematic review and meta-analysis to summarize existing information and quantify the risk of perioperative bleeding from chronic kidney disease. Methods: We screened 9376 citations from multiple databases for cohort studies published between 1990 and 2011. Studies that met our inclusion criteria included patients undergoing any major surgery, with a sample size of at least 100 patients with chronic kidney disease (as defined by the primary study authors with an elevated preoperative serum creatinine value or a low estimated glomerular filtration rate). Their outcomes had to be compared with a reference group of at least 100 patients without chronic kidney disease. Our primary outcomes were (1) receipt of perioperative blood transfusions and (2) need for reoperation for reasons of bleeding. Results: Twenty-three studies met our criteria for review (20 cardiac surgery, 3 non–cardiac surgery). Chronic kidney disease was associated with a greater risk of requiring blood transfusion (7 studies in cardiac surgery, totaling 22,718 patients) and weighted incidence in patients with normal kidney function was 53% and in chronic kidney disease was 73%; pooled odds ratio, 2.7 (95% confidence interval, 2.1–3.4). After adjustment for relevant factors, the association remained statistically significant in 4 studies. Chronic kidney disease was associated with more reoperation for reasons of bleeding (14 studies in cardiac surgery, totaling 569,715 patients) and weighted incidence in patients with normal kidney function was 2.4% and in chronic kidney disease was 2.7%; pooled odds ratio, 1.6 (95% confidence interval, 1.3–1.8). However, after adjustment for relevant factors (as done in 5 studies), the association was no longer statistically significant. Conclusions: Chronic kidney disease is associated with perioperative bleeding but not bleeding that required reoperation. Further studies should stage chronic kidney disease with the modern system, better define bleeding outcomes, and guide intervention to improve the safety of surgery in this at-risk population.