This cross-sectional study evaluates the prevalence of hearing loss among specific patient populations in Alberta and explores participant perceptions about patient-health care worker communication and potential solutions.

Purpose of review: Cardiovascular disease (CVD) accounts for nearly half of deaths among people receiving maintenance hemodialysis. Observational and interventional data suggest that higher serum magnesium, achieved through higher dialysate magnesium concentrations or oral supplementation, may improve cardiovascular outcomes and survival. This review synthesizes current evidence and provides context for an ongoing cluster-randomized trial that is testing whether a center-wide dialysate magnesium concentration of 0.75 mmol/L, versus ≤0.50 mmol/L, delivered as a policy and sustained for up to four years, reduces the risk of major cardiovascular-related hospitalizations. Sources of information: Peer-reviewed articles. Methods: We searched MEDLINE and EMBASE for observational and interventional studies evaluating serum or dialysate magnesium concentrations and cardiovascular outcomes in patients with chronic kidney disease and/or kidney failure. We appraised the methodological quality of interventional trials. This review is divided into four sections: (1) epidemiological associations between serum magnesium concentrations and CVD outcomes, (2) the impact of a higher concentration of dialysate magnesium on CVD outcomes, (3) the impact of oral magnesium supplementation on CVD outcomes, and (4) ongoing trials. Key findings: Twenty studies, including 10 randomized controlled trials, were reviewed. Systematic reviews and meta-analyses show that hypomagnesemia is associated with higher risks of cardiovascular events and all-cause mortality in hemodialysis. Interventional studies indicate that higher dialysate magnesium concentrations or oral supplementation can improve surrogate markers of vascular health, including less vascular calcification and stiffness. Higher dialysate concentrations may also lower cardiovascular mortality. Given encouraging but predominantly surrogate-based evidence, adequately powered randomized trials are warranted. Limitations: Most trials were small, single-center, and of short duration. They relied on surrogate endpoints, and there was heterogeneity in interventions and outcome measures.

The International Society of Nephrology-Global Kidney Health Atlas (ISN-GKHA) Interactive Map is a web-based, open-access platform designed to visualize global data on kidney health care capacity across world countries and regions. The platform presents indicators from the 2019 and 2023 ISN-GKHA surveys, allowing users to compare data across countries and regions (defined across International Society of Nephrology regions and World Bank Income Groups) over time. Key features include searchable and filterable data, interactive heatmap, barcode benchmarking, trend tracking, and exportable tables and graphics. It supports diverse users-including clinicians, researchers, policymakers, and advocates-by translating complex data into easily comprehensible and actionable items, such as kidney care capacity (organization and structures for kidney care), workforce availability, and policy implementation. It fosters stakeholder engagement, peer support, and collaborative planning to address disparities in kidney care. With continuous updates, user feedback integration, and planned enhancements such as improved data granularity, the Interactive Map is poised to be a powerful tool for driving evidence-informed policy, research, and advocacy to advance equitable kidney care globally.

AIMS:Obesity, systemic inflammation, and hyperinsulinemia are all features of metabolic syndrome and frequently occur together. We aimed to evaluate the association of body mass index (BMI) with incident non-communicable chronic disease (NCD) or all-cause mortality, independent of C-reactive protein (CRP) and fasting insulin. METHODS:This prospective population-representative cohort included Canadian residents aged ≥18 years from the Canadian Health Measure Survey. The exposures were BMI, CRP, and fasting insulin and the outcomes were mortality and incident NCDs. Results were externally validated using data from the United States (NHANES) and the United Kingdom (UK Biobank). We report hazards ratios (HRs) from Cox models using percentiles for the continuous exposures: 99th, 95th, 85th, 50th, 15th, 1st versus the 5th percentile. The fifth percentile for BMI was 19.6 kg/m2, which falls within the "healthy" range. RESULTS:Of ~8280 participants: 24.4% had obesity (BMI ≥30 kg/m2), 56.5% had inflammation (CRP >1 mg/L), and 36.6% had hyperinsulinemia (fasting insulin >75 pmol/L). Metabolic syndrome (≥1 feature) was more common without obesity (42.8%; ~3544 participants) than with obesity (22.9%; ~1896 participants). Participants were followed for a median of 6.7 years; 3.1% died and 7.4% developed an NCD (including 1.8% with cardiovascular disease). After adjustment for age, sex and smoking, CRP was positively associated with mortality (HR vs. referent for 1st and 99th %ile: 0.72 [95% confidence interval, CI 0.61, 0.84] and 7.67 [95% CI 2.89, 20.38]), as was fasting insulin (0.88 [95% CI 0.78, 0.99] and 3.22 [95% CI 1.12, 9.29] respectively). BMI was negatively associated with mortality (HR vs. referent for 1st and 95th %ile: 1.45 [95% CI 1.11, 1.88] and 0.46 [95% CI 0.22, 0.97]), although HR for the 99th %ile was non-significant (0.51 [95% CI 0.20, 1.27]). All three exposures were mostly positively associated with incident NCD but varied depending on the type of NCD. CONCLUSIONS:After adjustment for confounding by systemic inflammation and hyperinsulinemia, obesity was associated with a lower risk of death but with a higher risk of incident NCD. As there are more people with metabolic syndrome without obesity than with obesity, future research should prioritise the study of how to best diagnose, monitor and treat inflammation and hyperinsulinemia rather than obesity.

Chronic kidney disease (CKD) is associated with the accumulation of chemically diverse uremic metabolites, creating a need for rapid and multiplexed analytical platforms beyond conventional single-analyte assays. This work reports a high-throughput surface-enhanced Raman spectroscopy (SERS) platform for simultaneous analysis of CKD-related metabolites. It comprises a flexible SERS substrate composed of silver nanoparticles (AgNPs) on a polydimethylsiloxane (PDMS) film. AgNPs were synthesized directly on the PDMS surface via solvent-exchange-induced surface droplet reactions, yielding a dense, uniform distribution of plasmonic hot spots. Using adenine as a model analyte at a concentration of 1 × 10-6 M, the substrate showed a batch-to-batch variation of 7.32%, confirming its reproducibility. The AgNPs-PDMS substrate was subsequently integrated into a parallel microvolume plate format to detect five CKD-relevant metabolites, achieving the limit of detection (LOD) ≤ 2.5 × 10-4 M across the panel. To the best of our knowledge, this work presents the first SERS detection of quinaldic acid and 3-(3-hydroxyphenyl)-3-hydroxypropionic acid. As a proof-of-concept for clinical translation, the platform was used to quantify selected metabolites in serum from patients with kidney failure. This scalable polymer-based SERS platform provides a practical route toward parallel biochemical screening of CKD-associated metabolites.

RATIONALE & OBJECTIVE:Patients seen by nephrologists are highly complex, and clinical experience suggests this complexity has increased over time. This study compared temporal trends in the complexity profiles of inpatients seen by nephrologists to those seen by other physicians. STUDY DESIGN:Retrospective-cohort study. SETTING & PARTICIPANTS:Adult inpatients hospitalized between 2011 and 2020 in Alberta, Canada. EXPOSURE:(1) Physician groups involved during hospitalization and (2) calendar time. OUTCOME:Ten markers of complexity were evaluated before hospital admission, and 2 outcomes (death and placement in long-term care) were assessed after hospitalization. ANALYTICAL APPROACH:Generalized linear models to estimate absolute changes over the study period. RESULTS:Between 2011 and 2020, there were 1,621,630 hospital admissions among 971,051 patients. The number of nephrology inpatients seen annually rose by 44%, an increase larger than observed with other specialties (95% CI, 28.9-59.8). The percentage of inpatients seen by nephrologists in 2020 with complexity markers related to the number of specialty caregivers, number of physician caregivers, number of prescriptions, emergency department visits, and number of drug reactions increased by 6.1% (95% CI, 5.0-7.1), 6.0% (95% CI, 4.9-7.1) 1.9% (95% CI, 1.0-2.8), 1.5% (95% CI, 0.9-2.1), and 1.2% (95% CI, 0.4-2.0), respectively. The percentage of inpatients with frailty seen by nephrologists and with low primary-care attachment increased by 5.1% (95% CI, 4.2-6.0) and 3.5% (95% CI, 2.4-4.6), respectively. Except for frailty and number of prescriptions, the magnitude of the increases in these markers was larger for nephrology inpatients than for those cared for by other physicians. Secular changes in complexity were largely due to increases in characteristics other than age. Risks of death or placement in long-term care within 1 year of discharge decreased to a greater extent for inpatients cared for by nephrologists than among those cared for by other physicians. LIMITATIONS:Various markers of patient complexity were not evaluated. CONCLUSIONS:Volume and complexity of inpatients cared for by nephrologists have increased over time, a trend not explained by the increasing age of the population. However, the risks of death or need for long-term care fell more among patients cared for by nephrologists. PLAIN-LANGUAGE SUMMARY:Patients seen by nephrologists are highly complex, and clinical experience suggests that this complexity has increased over time. This study evaluated changes in various markers of patient complexity among hospitalized patients seen by nephrologists in Alberta, Canada, between 2011 and 2020. This study found increasing clinical complexity among patients seen by nephrologists, with changes greater than those observed among patients seen by other physician groups. Despite these changes showing increasing complexity among patients cared for by nephrologists, the risks of death or placement in long-term care within a year of hospital discharge decreased over time, and the decrease was greater among patients seen by nephrologists.

Background: People with hearing loss may have difficulty communicating with health care providers if not properly supported. Hearing loss is common among people with kidney failure. Outpatient hemodialysis centers may present communication barriers due to noisy machines and overlapping conversations. Tools, such as assistive listening devices, exist to help people with hearing loss communicate. If and how they should be used in the outpatient hemodialysis setting is unclear. Understanding the patient perspective is an important first step before implementing such solutions. Objective: Describe the communication-related experiences of patients with hearing loss when conversing with health care providers during hemodialysis treatment, focusing on perceptions about communication tools. Design: Qualitative descriptive. Setting: Outpatient hemodialysis centers in Calgary and Edmonton, Alberta, Canada. Participants: Adults with kidney failure receiving maintenance hemodialysis with self-reported hearing loss. Methods: Semi-structured individual interviews. Interviews were audio-recorded, transcribed, and abductively coded using a validated communication framework, a strategy to guide communication access in practice, and participants’ experiences. Results: Fourteen patients participated between October 2023 and January 2024. Patient perceptions about communication tools varied. We identified three themes that describe these differences: (1) communication tools may be needed in transitional or clinically complex situations, (2) patients with their own resources may rely less on center-provided tools, and (3) awareness and self-advocacy for support varies across patients. Limitations: The major limitation of this study is the lack of representation from patients with language barriers and those belonging to the Deaf community or with overlooked hearing difficulties. Consequently, results may not be transferable to all patients with hearing loss in Alberta or elsewhere. Conclusions: Communication support needs are both person-specific and context-dependent, varying across and within patients. Not all patients that may benefit from communication tools will be comfortable asking or accepting help. Clinicians should routinely check in with patients about their communication needs and offer a variety of tools to accommodate as needed.

Chronic kidney disease affects 850 million people worldwide and places a disproportionate burden on low-income and middle-income countries where access to timely diagnosis, treatment, and life-sustaining kidney replacement therapy (KRT) is restricted. In May, 2025, the 78th World Health Assembly adopted a resolution on kidney health that called on all member states to integrate kidney care into national strategies; enhance prevention, early detection, and timely management; strengthen primary care; expand access to KRT; and enhance capacity for measuring burden, progress, and return on investment. These ambitious commitments were followed by the Political Declaration of the UN High-Level Meeting on NCDs and Mental Health. Capitalising on the opportunities created by these two initiatives will depend on governance, political commitment, and accountability, along with technical tools, appropriate funding, and mechanisms to measure progress. This Health Policy offers a practical framework to help governments and partners operationalise the commitments from the resolution and political declaration, drawing on lessons from other non-communicable disease programmes and on countries’ experiences with kidney health policy.

The Kidney Disease: Improving Global Outcomes (KDIGO) 2026 Clinical Practice Guideline for the Management of Anemia in Chronic Kidney Disease (CKD) represents an update to the guideline published in 2012. Its scope includes diagnosis and evaluation of anemia; use of iron to treat iron deficiency and anemia in CKD; use of erythropoiesis-stimulating agents and hypoxia-inducible factor-prolyl hydroxylase inhibitors to treat anemia in CKD; and red blood cell transfusions to treat anemia in CKD. The guideline has been developed with patient partners, healthcare providers, and researchers around the world, with the goal to generate a useful resource for healthcare providers and patients by providing actionable recommendations. The development of this guideline followed an explicit process of evidence review and appraisal based on systematic reviews. The certainty of evidence and strength of recommendations follows the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. The guideline also provides practice points that provide clinical advice but are not supported by a systematic review. Limitations of the evidence are discussed. Research recommendations to address gaps in knowledge, and implications for policy and payment, are provided. The guideline targets a broad audience of healthcare providers, affected individuals, and stakeholders involved in the various aspects of anemia and CKD care.

Key PointsThe term, frailty, had unclear meaning for most participants but was commonly explained as weakness, dependence, and unmodifiable.Knowledge of frailty assessment tools and the evidence to support their prognostic utility was low among clinicians.Though patients and caregivers saw value in discussing frailty, the label of frailty was often viewed as pejorative.BackgroundFrailty is highly prevalent among individuals with kidney failure and independently associated with poor health outcomes. Identifying and managing frailty can inform prognosis and care but stakeholders' understanding of frailty and their perspectives on how to detect and manage it in routine kidney care are unknown.MethodsWe recruited participants from four Canadian kidney programs in Alberta, Manitoba, and Nova Scotia from January 2021 to June 2023. We conducted focus groups and semistructured interviews with patients (50 years or older with dialysis-dependent or nondependent kidney failure), caregivers, allied health care professionals, and nephrologists. We used qualitative description and inductive thematic analysis to describe their perspectives.ResultsNinety-one people participated: patients (N=31), caregivers (N=8), kidney allied health care professionals (N=38), and nephrologists (N=14). We identified three themes, each with subthemes: (1) What is frailty? All groups expressed uncertainty, but frailty was commonly described as physical, visible, inevitable, and fixed; (2) discussing frailty: the value of knowing what to expect with frailty, and frailty as a difficult topic to discuss; (3) frailty assessment and management: skepticism from patients and caregivers that frailty is measurable; support from clinicians for a systematic approach to identifying frailty but a lack of knowledge on multidisciplinary roles and potential interventions. For all groups, having actionable solutions after identifying frailty was key for acceptability and successful implementation.ConclusionsEducation on the nature and potentially modifiable aspects of frailty as well as the scope and potential benefits of frailty interventions is necessary for successful implementation of frailty detection and management in kidney care.

Background: In individuals receiving hemodialysis, lower serum magnesium concentrations are associated with a higher risk of death and cardiovascular disease and more discomfort from muscle cramps. Small trials suggest that increasing serum magnesium by using a higher concentration of dialysate magnesium may be beneficial. This protocol outlines a large, randomized trial examining the effects of adopting a high versus low concentration of dialysate magnesium as a hemodialysis center-wide policy on the risk of mortality, major adverse cardiovascular events, and the burden of muscle cramps. Objective: To determine whether implementing a dialysate magnesium concentration of 0.75 mmol/L versus ≤ 0.5 mmol/L as a hemodialysis center-wide policy, for up to 4 years, affects (1) the rate of all-cause mortality or major cardiovascular-related hospitalizations or (2) the level of discomfort individuals experience from muscle cramps. Design: Pragmatic, 2-arm, parallel-group, registry-based, open-label, 2-sided superiority cluster randomized trial. Hemodialysis centers were randomly allocated (1:1) to one of the 2 arms. The assignment was constrained by five center-level prognostic factors and stratified by province. Setting: 137 hemodialysis centers in four Canadian provinces—Ontario, British Columbia, Alberta, and Manitoba. The trial period is from April 4, 2022, to March 31, 2026. Outcomes will be analyzed after March 31, 2026, using provincial health care databases and self-reported questionnaires. Participants: Individuals who received maintenance hemodialysis at participating centers during the trial period. Intervention: Use of a dialysate magnesium concentration of either 0.75 mmol/L or ≤ 0.5 mmol/L as a center-wide policy during the trial period. Measurements: The two primary outcomes are (1) a composite of all-cause mortality or major cardiovascular-related hospitalization (a hospital admission with myocardial infarction, congestive heart failure, or ischemic stroke) recorded in large health care databases and (2) self-reported muscle cramps collected from questionnaires. Methods: Using an intent-to-treat approach, the intervention effect on the instantaneous rate of the primary composite outcome will be analyzed using a stratified Cox proportional hazards model accounting for center-level clustering. The observation time will be censored for provincial emigration or the trial end date. Self-reported muscle cramps will be analyzed using a cumulative link (proportional odds) model. All models will be stratified by province and adjusted for the covariates used to constrain randomization. Limitations: The trial start date was delayed in some centers due to post-pandemic supply disruptions (including discontinued dialysate formulations); however, all centers secured dialysate concentrates in alignment with the trial-allocated magnesium level. Conclusions: The results of this pragmatic trial will inform center-wide policy on the optimal dialysate magnesium concentration for patient health. Trial Registration: www.clinicaltrials.gov ; identifier: NCT04079582

A core feature of universal health coverage is equitable access to affordable care not exposing people to financial hardship. This study aims to provide a global overview on availability and access to medications and health technologies for delivery of optimal kidney care. An international survey of stakeholders (clinicians, policymakers, and patient advocates) from countries affiliated to the International Society of Nephrology was conducted from July to September 2022 on availability of tools and services for all aspects of kidney care and access to essential medications. Of 167 participating countries (97.4% of the global population), there were significant disparities in kidney care funding and service availability. Only 5 (n = 1) and 10% (n = 4) of countries in Latin America and Africa, respectively, publicly funded non-dialysis CKD care free at the point of delivery, compared to73% (n = 16) in Western Europe. Public funding (and free at point of delivery) for medications for dialysis and kidney transplantation was available in only 24% (n = 39) and 30% (n = 50) of countries worldwide, with the proportion increasing in line with country income levels. There was reduced capacity for the management of CKD mineral bone disease in low-income countries (LICs) - serum parathyroid hormone was available in only 26% (n = 5) of LICs and the ability to administer non-calcium-based phosphate binders and cinacalcet was also very limited in LICs [16% (n = 3) and 5% (n = 1), respectively]. Nutritional services like oral supplements were accessible in 32% (n = 6) of LICs versus 97% (n = 61) of high-income countries. This study highlights significant gaps in the global methods of funding and availability of medications, capacity for kidney disease monitoring, and capacity to treat complications of kidney disease to improve outcomes. Achieving universal and equitable access to essential medications and health technologies for kidney care is vital to tackle the rapidly growing global burden of kidney disease.

Chronic kidney disease is a major noncommunicable disease that affects approximately 850 million people worldwide and is associated with a high burden of morbidity and mortality, especially in low- and middle-income countries. The recent resolution on kidney health at the 78th World Health Assembly creates an unprecedented opportunity for concerted action on kidney disease to accelerate global progress on noncommunicable disease prevention and control. We illustrate these opportunities using a case-study format with 3 selected countries—Guatemala, Thailand, and Somalia—which together demonstrate how the unique challenges associated with chronic kidney disease can be effectively addressed by targeted action at the country level. From these early efforts at implementing the resolution’s commitments, 3 key lessons emerge for other countries to consider. First, developing a dedicated national strategy for kidney health is an essential step, which should be pursued together with integrating kidney health into other national policies for noncommunicable disease prevention and control. Second, strengthening capacity for the early detection and timely management of chronic kidney disease in primary care is arguably the highest kidney-related priority for all countries. Third, strengthening health data systems and surveillance infrastructure is critical for priority setting, resource allocation, addressing inequalities, assessing return on investment, and ensuring continuous quality improvement. In parallel with actions at the country level, the World Health Organization and other stakeholders, such as the International Society of Nephrology, can provide Member States with technical assistance and knowledge exchange related to essential medicines, key diagnostics, and kidney replacement. The International Society of Nephrology has commenced a multiyear strategy that will assist countries in implementing the resolution’s commitments; the first phase will culminate in an implementation summit at the 2027 World Congress of Nephrology in Dubai. These actions will help to translate the commitments of the 78th World Health Assembly resolution into action, improving kidney health and health equity worldwide.

Background: People undergoing hemodialysis (HD) take an average of 12 medications daily, with 93% prescribed at least one potentially inappropriate medication or dose. Polypharmacy is commonly defined as taking 5 or more medications per day; however, it can also refer to the use of inappropriate medication choices and doses. Polypharmacy can lead to serious health consequences, including drug-drug interactions, falls, and hospitalizations. Deprescribing, the process of stopping or gradually reducing the dose of a medication that may be causing harm or offers no benefit, can reduce polypharmacy among older adults. However, little research focuses on deprescribing in the HD population, and few tools exist to support deprescribing in HD. To address this gap, we developed and validated the STrategic Optimization of Medication Use in Patients on HemoDialysis (STOPMed-HD) intervention, a deprescribing toolkit which includes clinician-focused algorithms, monitoring forms, and evidence tables, and patient-facing information bulletins and videos. Co-developed with clinicians and patients, the toolkit reflects patient priorities and aligns with their deprescribing goals. This report describes the implementation and evaluation strategy of the STOPMed-HD intervention at 4 HD sites across Canada, and presents insights into barriers, facilitators, and key considerations for implementation. Knowledge mobilization and implementation methods: Our knowledge mobilization and implementation strategy involves a collaborative approach to implement the evidence-based deprescribing toolkit. Our strategy prioritizes engagement with several key partners, including patients and clinicians, to support implementation and foster a culture of deprescribing within HD units across Canada. Clinician buy-in at participating sites was established during toolkit development, and we continue to support clinicians throughout implementation at their respective HD units. Diverse patient partners have been actively involved since the inception of the study, and ongoing patient engagement remains central. To explore facilitators and barriers to uptake, we conducted interviews with patients and clinicians who participated in the 6-month deprescribing intervention at the Toronto site. Interviews at other sites will be completed in the coming months. The RE-AIM (Reach, Effectiveness, Adoption, Implementation, and Maintenance) framework guided our data collection and analysis approach. Key findings and implementation considerations: The 6-month deprescribing intervention has been implemented in Toronto, ON; Halifax, NS; Calgary, AB; and Victoria, BC. This report includes key barriers and facilitators identified from the Toronto site. Patient-level barriers include fear of withdrawal, medication dependence, disengagement, and lack of follow-up support, while facilitators include clear messaging about deprescribing and regular monitoring and follow-up. Clinician-level barriers involve time constraints and unclear deprescribing roles and responsibilities among the care team. Barriers faced by facilitators include a lack of evidence-based deprescribing tools, integration of deprescribing into routine practice, a deprescribing champion, and multidisciplinary collaboration. System-level challenges include inadequate resources, fragmented electronic medical record systems, and a need for further research on deprescribing outcomes in the HD population. Potential cost savings and sharing learnings across HD care teams are additional facilitators. Future directions: This study demonstrates the potential of a structured, evidence-informed deprescribing approach to enhance patient safety, reduce medication burden, support shared decision-making, and promote team-based medication management in HD. Challenges to sustainability and rollout remain, and further research is needed to identify scalable, sustainable strategies that support long-term success of deprescribing across diverse HD settings.

The Kidney Disease: Improving Global Outcomes (KDIGO) 2022 Clinical Practice Guideline for the Management of Diabetes in Chronic Kidney Disease (CKD) is an update of the KDIGO 2020 guideline. The guideline is aimed at a broad audience of clinicians treating people with diabetes and CKD. Topics with recommendations updated based on new evidence include Chapter 1: Comprehensive Care in Patients with Diabetes and CKD, and Chapter 4: Glucose-Lowering Therapies in Patients with Type 2 Diabetes (T2 D) and CKD. The content of previous chapters on glycemic monitoring and targets in patients with diabetes and CKD (Chapter 2), lifestyle interventions in patients with diabetes and CKD (Chapter 3), and approaches to the management of patients with diabetes and CKD (Chapter 5) are considered current and have not been changed. This updated guideline was developed through a rigorous process of evidence review and evaluation. Treatment approaches and guideline recommendations are based on systematic reviews of relevant studies and assessment of evidence quality. The strength of the recommendations follows the GRADE approach (Grading of Recommendations Assessment, Development and Evaluation). The limitations of the evidence are discussed, and areas where additional research is needed are identified.

Comorbidity measures, such as the Charlson Comorbidity Index, are commonly used in risk adjustment models to account for variability in disease burden. This narrative synthesis describes and critiques available comorbidity indices and offers implementation guidance to researchers based on a critical review of existing literature. First, common comorbidity measures are described. Instruments derived using case definitions, grouping of International Classification of Diseases (ICD) codes, and mapping of dispensed medications to chronic conditions are presented. Comorbidity indices that combine diagnostic and medication data are also introduced. No single option consistently outperforms the rest. Next, important considerations when applying a comorbidity index are described. It is crucial to respect temporality and exclude health events that arise after the study index date. Researchers must also weigh the interpretability of using a weighted sum against the flexibility of using a large set of binary variables. When modelling long-term outcomes, there are benefits to applying a one-year look-back window and augmenting data via linkage. For short-term outcomes, certain chronic conditions may exhibit a protective association; however, not all indices capture these relationships. Implementation of these findings will improve the interpretability of comorbidity measures and the quality of future studies.