Risk-based lung cancer screening performance in a universal healthcare setting

Globally, lung cancer is the leading cause of cancer death. Previous trials demonstrated that low-dose computed tomography lung cancer screening of high-risk individuals can reduce lung cancer mortality by 20% or more. Lung cancer screening has been approved by major guidelines in the United States, and over 4,000 sites offer screening. Adoption of lung screening outside the United States has, until recently, been slow. Between June 2017 and May 2019, the Ontario Lung Cancer Screening Pilot successfully recruited 7,768 individuals at high risk identified by using the PLCOm2012noRace lung cancer risk prediction model. In total, 4,451 participants were successfully screened, retained and provided with high-quality follow-up, including appropriate treatment. In the Ontario Lung Cancer Screening Pilot, the lung cancer detection rate and the proportion of early-stage cancers were 2.4% and 79.2%, respectively; serious harms were infrequent; and sensitivity to detect lung cancers was 95.3% or more. With abnormal scans defined as ones leading to diagnostic investigation, specificity was 95.5% (positive predictive value, 35.1%), and adherence to annual recall and early surveillance scans and clinical investigations were high (>85%). The Ontario Lung Cancer Screening Pilot provides insights into how a risk-based organized lung screening program can be implemented in a large, diverse, populous geographic area within a universal healthcare system.

Adherence to guidance for prioritizing higher risk groups for breast cancer screening during the COVID-19 pandemic in the Ontario Breast Screening Program: a descriptive study

BACKGROUND

Breast cancer screening in Ontario, Canada, was deferred during the first wave of the COVID-19 pandemic, and a prioritization framework to resume services according to breast cancer risk was developed. The purpose of this study was to assess the impact of the pandemic within the Ontario Breast Screening Program (OBSP) by comparing total volumes of screening mammographic examinations and volumes of screening mammographic examinations with abnormal results before and during the pandemic, and to assess backlogs on the basis of adherence to the prioritization framework.

METHODS

A descriptive study was conducted among women aged 50 to 74 years at average risk and women aged 30 to 69 years at high risk, who participated in the OBSP. Percentage change was calculated by comparing observed monthly volumes of mammographic examinations from March 2020 to March 2021 with 2019 volumes and proportions by risk group. We plotted estimates of backlog volumes of mammographic examinations by risk group, comparing pandemic with prepandemic screening practices. Volumes of mammographic examinations with abnormal results were plotted by risk group.

RESULTS

Volumes of mammographic examinations in the OBSP showed the largest declines in April and May 2020 (> 99% decrease) and returned to prepandemic levels as of March 2021, with an accumulated backlog of 340 876 examinations. As of March 2021, prioritization had reduced the backlog volumes of screens for participants at high risk for breast cancer by 96.5% (186 v. 5469 expected) and annual rescreens for participants at average risk for breast cancer by 13.5% (62 432 v. 72 202 expected); there was a minimal decline for initial screens. Conversely, the backlog increased by 7.6% for biennial rescreens (221 674 v. 206 079 expected). More than half (59.4%) of mammographic examinations with abnormal results were for participants in the higher risk groups.

INTERPRETATION

Prioritizing screening for those at higher risk for breast cancer may increase diagnostic yield and redirect resources to minimize potential long-term harms caused by the pandemic. This further supports the clinical utility of risk-stratified cancer screening.

Predicting kidney failure risk after acute kidney injury among people receiving nephrology clinic care

Background

Outcomes after acute kidney injury (AKI) are well described, but not for those already under nephrology clinic care. This is where discussions about kidney failure risk are commonplace. We evaluated whether the established kidney failure risk equation (KFRE) should account for previous AKI episodes when used in this setting.

Methods

This observational cohort study included 7491 people referred for nephrology clinic care in British Columbia in 2003–09 followed to 2016. Predictors were previous Kidney Disease: Improving Global Outcomes–based AKI, age, sex, proteinuria, estimated glomerular filtration rate (eGFR) and renal diagnosis. Outcomes were 5-year kidney failure and death. We developed cause-specific Cox models (AKI versus no AKI) for kidney failure and death, stratified by eGFR (</≥30 mL/min/1.73 m²). We also compared prediction models comparing the 5-year KFRE with two refitted models, one with and one without AKI as a predictor.

Results

AKI was associated with increased kidney failure (33.1% versus 26.3%) and death (23.8% versus 16.8%) (P  < 0.001). In Cox models, AKI was independently associated with increased kidney failure in those with an eGFR ≥30 mL/min/1.73 m² {hazard ratio [HR] 1.35 [95% confidence interval (CI) 1.07–1.70]}, no increase in those with eGFR <30 mL/min/1.73 m² ([HR 1.05 95% CI 0.91–1.21)] and increased mortality in both subgroups [respective HRs 1.89 (95% CI 1.56–2.30) and 1.43 (1.16–1.75)]. Incorporating AKI into a refitted kidney failure prediction model did not improve predictions on comparison of receiver operating characteristics (P = 0.16) or decision curve analysis. The original KFRE calibrated poorly in this setting, underpredicting risk.

Conclusions

AKI carries a poorer long-term prognosis among those already under nephrology care. AKI may not alter kidney failure risk predictions, but the use of prediction models without appreciating the full impact of AKI, including increased mortality, would be simplistic. People with kidney diseases have risks beyond simply kidney failure. This complexity and variability of outcomes of individuals is important.

Prescription Patterns in Dialysis Patients: Differences Between Hemodialysis and Peritoneal Dialysis Patients and Opportunities for Deprescription

Background:

Patients treated with maintenance dialysis are at high risk of polypharmacy given their many comorbidities as well as complications from their disease state and treatment. The prescribing patterns and burden of polypharmacy in patients treated with maintenance dialysis, and specifically the difference between hemodialysis (HD) and peritoneal dialysis (PD) prescribing, are not well characterized.

Objectives:

The objectives of this study were to review the prescribing patterns for patients treated with maintenance dialysis, to compare prescribing pattern between HD and PD, and to identify opportunities for deprescription.

Design:

This is a retrospective cohort study.

Setting:

This study was conducted in all dialysis centers in British Columbia, Canada.

Patients:

Patients who were receiving chronic dialysis (>120 days on the same dialysis modality) between June 3 and October 1, 2015, and registered in the British Columbia (BC) Renal Patient Records and Outcomes Management Information System.

Measurements:

Patient demographics as well as both prescription and non-prescription medications were collected. Comparison of discrete and continuous variables was made by chi-square analysis and independent t test, respectively. All statistical tests were 2-sided, and a P value of <.05 was considered statistically significant.

Methods:

Medications were classified by indication: (1) management of renal complications, (2) cardiovascular (CV) medications, (3) diabetes medications, or (4) management of symptoms, and then classified as to whether they were a “potentially inappropriate medication” (PIM) or not. Ethics approval was granted from the University of British Columbia Research and Ethics Board.

Results:

In total, 3017 patients met inclusion criteria (2243 HD, 774 PD). The mean age was 66.2 ± 14.8 years. The HD group had more patients over 80 years old (22.1% vs 12.5%) and more patients with diabetes and CV disease. The mean number (standard deviation [SD]) of discrete prescribed medications was 17.71 (5.72) overall with more medications in the HD group versus the PD group. The mean number of medications increased with dialysis vintage in both groups. HD patients were on more medications for renal complications and management of symptoms than PD patients. Of the total number of medications prescribed, 5.02 (2.78) were classified as a PIM, with the number of PIMs higher in HD vs PD patients: 5.37 (2.83) versus 4.02 (2.37).

Limitations:

In BC, some of the medications are prescribed through standardized protocols and may not be comparable with other Canadian provinces. We report here prescribing patterns, not utilization patterns, as we are not able to ascertain actual consumption of prescribed medication.

Conclusion:

This study reviews and characterizes both the prescription and non-prescription medication prescribed to HD patients and PD patients in BC. Pill burden in both groups is high, as is the prescription of PIMs. Patients receiving maintenance HD receive more overall medications and more PIMs. These results highlight areas of opportunities for future systematic and patient-informed deprescription initiatives in both patient groups.

Evaluating a New International Risk-Prediction Tool in IgA Nephropathy

IMPORTANCE

Although IgA nephropathy (IgAN) is the most common glomerulonephritis in the world, there is no validated tool to predict disease progression. This limits patient-specific risk stratification and treatment decisions, clinical trial recruitment, and biomarker validation.

OBJECTIVE

To derive and externally validate a prediction model for disease progression in IgAN that can be applied at the time of kidney biopsy in multiple ethnic groups worldwide.

DESIGN, SETTING, AND PARTICIPANTS

We derived and externally validated a prediction model using clinical and histologic risk factors that are readily available in clinical practice. Large, multi-ethnic cohorts of adults with biopsy-proven IgAN were included from Europe, North America, China, and Japan.

MAIN OUTCOMES AND MEASURES

Cox proportional hazards models were used to analyze the risk of a 50% decline in estimated glomerular filtration rate (eGFR) or end-stage kidney disease, and were evaluated using the R2D measure, Akaike information criterion (AIC), C statistic, continuous net reclassification improvement (NRI), integrated discrimination improvement (IDI), and calibration plots.

RESULTS

The study included 3927 patients; mean age, 35.4 (interquartile range, 28.0-45.4) years; and 2173 (55.3%) were men. The following prediction models were created in a derivation cohort of 2781 patients: a clinical model that included eGFR, blood pressure, and proteinuria at biopsy; and 2 full models that also contained the MEST histologic score, age, medication use, and either racial/ethnic characteristics (white, Japanese, or Chinese) or no racial/ethnic characteristics, to allow application in other ethnic groups. Compared with the clinical model, the full models with and without race/ethnicity had better R2D (26.3% and 25.3%, respectively, vs 20.3%) and AIC (6338 and 6379, respectively, vs 6485), significant increases in C statistic from 0.78 to 0.82 and 0.81, respectively (ΔC, 0.04; 95% CI, 0.03-0.04 and ΔC, 0.03; 95% CI, 0.02-0.03, respectively), and significant improvement in reclassification as assessed by the NRI (0.18; 95% CI, 0.07-0.29 and 0.51; 95% CI, 0.39-0.62, respectively) and IDI (0.07; 95% CI, 0.06-0.08 and 0.06; 95% CI, 0.05-0.06, respectively). External validation was performed in a cohort of 1146 patients. For both full models, the C statistics (0.82; 95% CI, 0.81-0.83 with race/ethnicity; 0.81; 95% CI, 0.80-0.82 without race/ethnicity) and R2D (both 35.3%) were similar or better than in the validation cohort, with excellent calibration.

CONCLUSIONS AND RELEVANCE

In this study, the 2 full prediction models were shown to be accurate and validated methods for predicting disease progression and patient risk stratification in IgAN in multi-ethnic cohorts, with additional applications to clinical trial design and biomarker research.

The BC Glomerulonephritis Network: Improving Access and Reducing the Cost of Immunosuppressive Treatments for Glomerular Diseases

Glomerulonephritis (GN) is a common cause of end-stage renal disease in Canada and worldwide, and results in significant health care resource utilization and patient morbidity. However, GN has not been a traditional priority of provincial renal health care organizations, despite the known benefits to health services delivery and patient outcomes from integrated provincial care in other types of chronic kidney disease. To address this deficiency, the British Columbia (BC) Provincial Renal Agency created the BC GN Network in 2013 to coordinate provincial GN health services delivery informed by robust population-level data capture on all GN patients in the province via the BC GN Registry. This report describes the use of the BC GN Network infrastructure to systematically develop and evaluate a provincial GN drug formulary to improve patient and physician access to evidence-based immunosuppressive treatments for GN in a cost-efficient manner that successfully halted historical trends of increasing medication costs. An example is provided of using the provincial infrastructure to implement and subsequently evaluate an evidence-informed health policy of converting brand to generic tacrolimus for the treatment of GN. The BC GN Network, including the provincial drug formulary and data infrastructure, is an example of the benefits of expanding the mandate of provincial renal health administrative organizations to include the care of patients with GN, and constitutes a viable health delivery model that can be implemented in other Canadian provinces to achieve similar goals.

Femoral Arteriovenous Grafts for Hemodialysis: Retrospective Comparison With Upper Extremity Grafts and Fistulas

Background:

Femoral arteriovenous grafts are rarely used to provide vascular access for dialysis patients. This is likely due, in part, to historically high rates of graft loss from infection and thrombosis. However, for selected patients who have exhausted all access options in the upper extremity, femoral grafts can provide additional sites for access creation and may be preferred over central venous catheters.

Objective:

We sought to demonstrate that femoral grafts can provide a reliable and safe alternative to central venous catheters for selected patients.

Methods:

A single-center retrospective review in Vancouver, Canada, from April 1, 2008, to March 31, 2012, was conducted. All patients with new arteriovenous access (grafts and fistulas) created during the study period were included in the study population and followed for a minimum of 2 years. Comparisons of patency (primary, secondary, and functional) and complications (infectious and noninfectious) were made between the different access types.

Results:

Thirteen patients with femoral grafts were compared with 22 patients with arm grafts and 384 patients with fistulas. Femoral grafts had higher rates of thrombosis (46% with a thrombotic event) and a higher requirement for interventions (1.3 angioplasties and 0.12 thrombolytic procedures per patient per year). However, compared with arm grafts, femoral grafts had superior secondary and functional patency. No difference in patency was seen when comparing femoral grafts with upper extremity fistulas. Only 2 patients with femoral grafts required antibiotics for infection, and no grafts were lost to infection.

Conclusions:

For patients with limited access options remaining, femoral grafts may provide an additional form of vascular access before resorting to catheter use. Our study shows that with appropriate patient selection, femoral grafts have low infection rates and patency that is comparable with other access types.

The need for improved uptake of the KDIGO glomerulonephritis guidelines into clinical practice in Canada: a survey of nephrologists

Background

The lack of glomerulonephritis (GN) guidelines has historically contributed to substantial variability in the treatment of GN. We hypothesize that there are barriers to GN guideline implementation leading to incomplete translation of the 2012 KDIGO GN guidelines into patient care, and that current practice patterns deviate from guideline recommendations.

Methods

Adult nephrologists in Canada (N = 390) were surveyed using a web-based tool. The survey of 40 questions captured physician demographics, self-reported GN case load, treatment approaches and barriers to guideline implementation.

Results

The response rate was 44%. Physicians report seeing six (IQR 4,10) new cases of idiopathic GN every 6 months. The majority treat ANCA GN according to guidelines, but 9–37% treat nephrotic focal segmental glomerulosclerosis or membranous nephropathy with non-recommended immunosuppression and 6–9% do not treat with any immunotherapy, whereas 26% treat subnephrotic disease with immunosuppression. The majority indicated that standardized care tools would improve patient care, but they were only available to 25–44%. Patient education tools and nursing support are unavailable to 87 and 67%, respectively; insurance coverage for immune therapies is poorly accessible to 84%, yet 86% feel this would improve care and 96% of physicians support comparing their practice with benchmarks from provincial GN registries.

Conclusions

We show that 2 years after the publication of the KDIGO GN guidelines, 15–46% of Canadian nephrologists report treatment strategies not in keeping with guideline recommendations. We identify barriers to guideline implementation and widespread physician support for initiatives that address these barriers to improve patient care.

Bayesian adjustment for measurement error in continuous exposures in an individually matched case-control study

BACKGROUND

In epidemiological studies explanatory variables are frequently subject to measurement error. The aim of this paper is to develop a Bayesian method to correct for measurement error in multiple continuous exposures in individually matched case-control studies. This is a topic that has not been widely investigated. The new method is illustrated using data from an individually matched case-control study of the association between thyroid hormone levels during pregnancy and exposure to perfluorinated acids. The objective of the motivating study was to examine the risk of maternal hypothyroxinemia due to exposure to three perfluorinated acids measured on a continuous scale. Results from the proposed method are compared with those obtained from a naive analysis.

METHODS

Using a Bayesian approach, the developed method considers a classical measurement error model for the exposures, as well as the conditional logistic regression likelihood as the disease model, together with a random-effect exposure model. Proper and diffuse prior distributions are assigned, and results from a quality control experiment are used to estimate the perfluorinated acids' measurement error variability. As a result, posterior distributions and 95% credible intervals of the odds ratios are computed. A sensitivity analysis of method's performance in this particular application with different measurement error variability was performed.

RESULTS

The proposed Bayesian method to correct for measurement error is feasible and can be implemented using statistical software. For the study on perfluorinated acids, a comparison of the inferences which are corrected for measurement error to those which ignore it indicates that little adjustment is manifested for the level of measurement error actually exhibited in the exposures. Nevertheless, a sensitivity analysis shows that more substantial adjustments arise if larger measurement errors are assumed.

CONCLUSIONS

In individually matched case-control studies, the use of conditional logistic regression likelihood as a disease model in the presence of measurement error in multiple continuous exposures can be justified by having a random-effect exposure model. The proposed method can be successfully implemented in WinBUGS to correct individually matched case-control studies for several mismeasured continuous exposures under a classical measurement error model.