Probabilistic precision calculations for the planning of studies assessing negative binomial rates.

PURPOSE: Outcome variables that are assumed to follow a negative binomial distribution are frequently used in both clinical and epidemiological studies. Epidemiological studies, particularly those performed by pharmaceutical companies often aim to describe a population rather than compare treatments. Such descriptive studies are often analysed using confidence intervals. While precision calculations and sample size calculations are not always performed in these settings, they have the important role of setting expectations of what results the study may generate. Current methods for precision calculations for the negative binomial rate are based on plugging in parameter values into the confidence interval formulae. This method has the downside of ignoring the randomness of the confidence interval limits. To enable better practice for precision calculations, methods are needed that address the randomness. METHODS: Using the well-known delta-method we develop a method for calculating the precision probability, that is, the probability of achieving a certain width. We assess the performance of the method in smaller samples through simulations. RESULTS: The method for the precision probability performs well in small to medium sample sizes, and the usefulness of the method is demonstrated through an example. CONCLUSIONS: We have developed a simple method for calculating the precision probability for negative binomial rates. This method can be used when planning epidemiological studies in for example, asthma, while correctly taking the randomness of confidence intervals into account.

Risk of Subsequent Events in Patients With Minor Ischemic Stroke or High-Risk Transient Ischemic Attack.

This study aimed to present the prognosis after minor acute ischemic stroke (AIS) or transient ischemic attack (TIA), using a definition of subsequent stroke in accordance with recent clinical trials. In total, 9,506 patients with minor AIS (National Institutes of Health Stroke Scale ≤ 5) or high-risk TIA (acute lesions or ≥ 50% cerebral artery steno-occlusion) admitted between November 2010 and October 2013 were included. The primary outcome was the composite of stroke (progression of initial event or a subsequent event) and all-cause mortality. The cumulative incidence of stroke or death was 11.2% at 1 month, 13.3% at 3 months and 16.7% at 1 year. Incidence rate of stroke or death in the first month was 12.5 per 100 person-months: highest in patients with large artery atherosclerosis (17.0). The risk of subsequent events shortly after a minor AIS or high-risk TIA was substantial, particularly in patients with large artery atherosclerosis.

A metabolomics-based molecular pathway analysis of how the sodium-glucose co-transporter-2 inhibitor dapagliflozin may slow kidney function decline in patients with diabetes.

AIM: To investigate which metabolic pathways are targeted by the sodium-glucose co-transporter-2 inhibitor dapagliflozin to explore the molecular processes involved in its renal protective effects. METHODS: An unbiased mass spectrometry plasma metabolomics assay was performed on baseline and follow-up (week 12) samples from the EFFECT II trial in patients with type 2 diabetes with non-alcoholic fatty liver disease receiving dapagliflozin 10 mg/day (n = 19) or placebo (n = 6). Transcriptomic signatures from tubular compartments were identified from kidney biopsies collected from patients with diabetic kidney disease (DKD) (n = 17) and healthy controls (n = 30) from the European Renal cDNA Biobank. Serum metabolites that significantly changed after 12 weeks of dapagliflozin were mapped to a metabolite-protein interaction network. These proteins were then linked with intra-renal transcripts that were associated with DKD or estimated glomerular filtration rate (eGFR). The impacted metabolites and their protein-coding transcripts were analysed for enriched pathways. RESULTS: Of all measured (n = 812) metabolites, 108 changed (P < 0.05) during dapagliflozin treatment and 74 could be linked to 367 unique proteins/genes. Intra-renal mRNA expression analysis of the genes encoding the metabolite-associated proteins using kidney biopsies resulted in 105 genes that were significantly associated with eGFR in patients with DKD, and 135 genes that were differentially expressed between patients with DKD and controls. The combination of metabolites and transcripts identified four enriched pathways that were affected by dapagliflozin and associated with eGFR: glycine degradation (mitochondrial function), TCA cycle II (energy metabolism), L-carnitine biosynthesis (energy metabolism) and superpathway of citrulline metabolism (nitric oxide synthase and endothelial function). CONCLUSION: The observed molecular pathways targeted by dapagliflozin and associated with DKD suggest that modifying molecular processes related to energy metabolism, mitochondrial function and endothelial function may contribute to its renal protective effect.

Characteristics, Symptom Severity, and Experiences of Patients Reporting Chronic Kidney Disease in the PatientsLikeMe Online Health Community: Retrospective and Qualitative Study.

BACKGROUND: Chronic kidney disease (CKD) is a major global health burden, and is associated with increased adverse outcomes, poor quality of life, and substantial health care costs. While there is an increasing need to build patient-centered pathways for improving CKD management in clinical care, data in this field are scarce. OBJECTIVE: The aim of this study was to understand patient-reported experiences, symptoms, outcomes, and treatment journeys among patients with CKD through a retrospective and qualitative approach based on data available through PatientsLikeMe (PLM), an online community where patients can connect and share experiences. METHODS: Adult members (aged ≥18 years) with self-reported CKD within 30 days of enrollment, who were not on dialysis, and registered between 2011 and 2018 in the PLM community were eligible for the retrospective study. Patient demographics and disease characteristics/symptoms were collected from this retrospective data set. Qualitative data were collected prospectively through semistructured phone interviews in a subset of patients, and questions were oriented to better understand patients' experiences with CKD and its management. RESULTS: The retrospective data set included 1848 eligible patients with CKD, and median age was 56 years. The majority of patients were female (1217/1841, 66.11%) and most were US residents (1450/1661, 87.30%). Of the patients who reported comorbidities (n=1374), the most common were type 2 diabetes (783/1374, 56.99%), hypertension (664/1374, 48.33%), hypercholesterolemia (439/1374, 31.95%), and diabetic neuropathy (376/1374, 27.37%). The most commonly reported severe or moderate symptoms in patients reporting these symptoms were fatigue (347/484, 71.7%) and pain (278/476, 58.4%). In the qualitative study, 18 eligible patients (13 females) with a median age of 60 years and who were mainly US residents were interviewed. Three key concepts were identified by patients to be important to optimal care and management: listening to patient needs, coordinating health care across providers, and managing clinical care. CONCLUSIONS: This study provides a unique source of real-world information on the patient experience of CKD and its management by utilizing the PLM network. The results reveal the challenges these patients face living with an array of symptoms, and report key concepts identified by patients that can be used to further improve clinical care and management and inform future CKD studies.

Disease Burden Following Non-Cardioembolic Minor Ischemic Stroke or High-Risk TIA: A GWTG-Stroke Study.

BACKGROUND: Limited real-world data are available on outcomes following non-cardioembolic minor ischemic stroke (IS) or high-risk transient ischemic attack (TIA), particularly in the United States (US). We examined outcomes and Medicare payments following any severity IS or TIA as well as the subgroup with minor IS or high-risk TIA. METHODS: Medicare beneficiaries >65 years were identified using US nationwide Get with the Guidelines (GWTG)-Stroke Registry linked to Medicare claims data. The cohort consisted of patients enrolled in Medicare fee-for-service plan, hospitalized with non-cardioembolic IS or TIA between 2011 and 2014, segmenting a subgroup with minor IS (National Institute of Health Stroke Scale [NIHSS] ≤5) or high-risk TIA (ABCD2-score ≥6) compatible with the THALES clinical trial population. Outcomes included functional status at discharge, clinical outcomes (all-cause mortality, ischemic stroke, and hemorrhagic stroke, individually and as a composite), hospitalizations, and population average inpatient Medicare payments following non-cardioembolic IS or TIA. RESULTS: The THALES-compatible cohort included 62,518 patients from 1471 hospitals. At discharge, 37.0% were unable to ambulate without assistance, and 96.2% were prescribed antiplatelet therapy. Cumulative incidences at 30 days, 90 days, and 1 year for the composite outcome were 3.7%, 7.6%, and 17.2% and 2.4%, 4.0%, and 7.3% for subsequent stroke. The mean Medicare payment for the index hospitalization was $7951. The cumulative all-cause inpatient Medicare spending per patient (with or without any subsequent admission) at 30 days and 1 year from discharge was $1451 and $8105, respectively. CONCLUSIONS: The burden of illness for minor IS/high-risk TIA patients indicates an important unmet need. Improved therapeutic options may offer a significant impact on both patient outcomes and Medicare spending.

Randomised, blinded, cross-over evaluation of the palatability of and preference for different potassium binders in participants with chronic hyperkalaemia in the USA, Canada and Europe: the APPETIZE study.

OBJECTIVES: Traditional potassium (K+) binders for treating hyperkalaemia are unpalatable and poorly tolerated. Newer K+ binders are reportedly better tolerated; however, no published data describe their palatability, a determinant of long-term adherence. This study evaluated the palatability of and preference for three K+ binders: sodium and calcium polystyrene sulfonate (S/CPS), sodium zirconium cyclosilicate (SZC) and calcium patiromer sorbitex (patiromer). DESIGN: Phase 4, randomised, participant-blinded, cross-over study. Participants were randomised to one of six taste sequences and, using a 'sip and spit' approach, tasted each K+ binder before completing a survey. SETTING: 17 centres across the USA, Canada and European Union. PARTICIPANTS: 144 participants with chronic kidney disease, hyperkalaemia and no recent use of K+ binders. MAIN OUTCOME MEASURES: For the primary (USA) and key secondary (Canada and European Union) endpoints, participants rated palatability attributes (taste, texture, smell and mouthfeel) and willingness to take each K+ binder on a scale of 0-10 (rational evaluation). Feelings about each attribute, and the idea of taking the product once daily, were evaluated using a non-verbal, visual measure of emotional response. Finally, participants ranked the K+ binders according to palatability. RESULTS: In each region, SZC and patiromer outperformed S/CPS on overall palatability (a composite of taste, texture, smell and mouthfeel), based on rational evaluation and emotional response. Taking the product once daily was more appealing for SZC and patiromer, creating greater receptivity than the idea of taking S/CPS. The emotional response to mouthfeel had the strongest influence on feelings about taking each product. In each region, a numerically greater proportion of participants ranked SZC as the most preferred K+ binder versus patiromer or S/CPS. CONCLUSIONS: Preference for more palatable K+ binders such as SZC and patiromer may provide an opportunity to improve adherence to long-term treatment of hyperkalaemia. TRIAL REGISTRATION NUMBER: NCT04566653.

Gastric Bypass vs Diet and Cardiovascular Risk Factors: A Nonrandomized Controlled Trial.

Importance: Roux-en-Y gastric bypass (RYGB) is associated with reduced cardiovascular (CV) risk factors, morbidity, and mortality. Whether these effects are specifically induced by the surgical procedure or the weight loss is unclear. Objective: To compare 6-week changes in CV risk factors in patients with obesity undergoing matching caloric restriction and weight loss by RYGB or a very low-energy diet (VLED). Design, Setting, and Participants: This nonrandomized controlled study (Impact of Body Weight, Low Calorie Diet, and Gastric Bypass on Drug Bioavailability, Cardiovascular Risk Factors, and Metabolic Biomarkers [COCKTAIL]) was conducted at a tertiary care obesity center in Norway. Participants were individuals with severe obesity preparing for RYGB or a VLED. Recruitment began February 26, 2015; the first patient visit was on March 18, 2015, and the last patient visit (9-week follow-up) was on August 9, 2017. Data were analyzed from April 30, 2021, through June 29, 2023. Interventions: VLED alone for 6 weeks or VLED for 6 weeks after RYGB; both interventions were preceded by 3-week LED. Main Outcomes and Measures: Between-group comparisons of 6-week changes in CV risk factors. Results: Among 78 patients included in the analyses, the mean (SD) age was 47.5 (9.7) years; 51 (65%) were women, and 27 (35%) were men. Except for a slightly higher mean (SD) body mass index of 44.5 (6.2) in the RYGB group (n = 41) vs 41.9 (5.4) in the VLED group (n = 37), baseline demographic and clinical characteristics were similar between groups. Major atherogenic blood lipids (low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol, apolipoprotein B, lipoprotein[a]) were reduced after RYGB in comparison with VLED despite a similar fat mass loss. Mean between-group differences were -17.7 mg/dL (95% CI, -27.9 to -7.5), -17.4 mg/dL (95% CI, -29.8 to -5.0) mg/dL, -9.94 mg/dL (95% CI, -15.75 to -4.14), and geometric mean ratio was 0.55 U/L (95% CI, 0.42 to 0.72), respectively. Changes in glycemic control and blood pressure were similar between groups. Conclusions and Relevance: This study found that clinically meaningful reductions in major atherogenic blood lipids were demonstrated after RYGB, indicating that RYGB may reduce CV risk independent of weight loss. Trial Registration: ClinicalTrials.gov Identifier: NCT02386917.

Burden of systemic lupus erythematosus in clinical practice: baseline data from the SLE Prospective Observational Cohort Study (SPOCS) by interferon gene signature.

OBJECTIVE: The longitudinal Systemic Lupus Erythematosus Prospective Observational Cohort Study (SPOCS) aims to assess SLE disease course overall and according to type I interferon 4 gene signature (IFNGS). Here, we describe SPOCS patient characteristics by IFNGS and baseline disease activity. METHODS: SPOCS (NCT03189875) is an international study of patients with SLE according to Systemic Lupus International Collaborating Clinics (SLICC)/American College of Rheumatology (ACR) criteria. Enrolled patients from 135 centres in 8 countries were followed biannually for ≤3 years from June 2017 to November 2022. Baseline demographics, disease characteristics, organ system involvement/damage and flares were analysed descriptively according to SLE Disease Activity Index-2000 score (SLEDAI-2K <10/≥10) and IFNGS status (high/low). RESULTS: The study population (n=823) was 93.2% female, with mean (SD) age 45.3 (13.9) years and 11.1 (9.2) years since diagnosis; 52.4% had baseline SLICC/ACR Damage Index score ≥1. Patients with SLEDAI-2K scores ≥10 (241 of 584, 41.3%) vs <10 were younger (mean 42.8 (13.7) vs 46.6 (14.2) years; nominal p=0.001), had shorter SLE duration (10.4 (8.6) vs 12.4 (9.6) years; nominal p=0.012) and more severe flares (12.9% vs 5.3%; nominal p=0.001). IFNGS-high patients (522 of 739, 70.6%) were younger than IFNGS-low patients at first SLE manifestation (30.0 (12.7) vs 36.8 (14.6) years; nominal p<0.001). Proportions of IFNGS-high patients differed according to race (nominal p<0.001), with higher proportions among Asian (83.3%) and black (86.5%) versus white patients (63.5%). Greater proportions of IFNGS-high versus IFNGS-low patients had haematological (12.6% vs 4.1%), immunological (74.4% vs 45.6%) or dermal (69.7% vs 62.2%) involvement. CONCLUSIONS: We identified key characteristics of patients with high disease activity and/or elevated type I IFN signalling, populations with SLE with high unmet needs. Baseline SLEDAI-2K ≥10 was associated with shorter disease duration and more severe flares. IFNGS-high patients were younger at diagnosis and had distinct patterns of organ involvement, compared with IFNGS-low patients.

Age in relation to comorbidity and outcome in patients with high-risk TIA or minor ischemic stroke: A Swedish national observational study.

INTRODUCTION: Recent trials report positive results for preventing vascular events with dual antiplatelet therapy (DAPT) in patients with high-risk TIA or minor ischemic stroke. We aimed to investigate this population regarding influence of age on vascular risk factors, hospital stay and mortality. PATIENTS AND METHODS: Data on patients aged 40-100 years with TIA or ischemic stroke in the Swedish Stroke Register during 2012-13 were linked with national registers. To identify patients with high-risk TIA (ABCD2 ≥6) or minor ischemic stroke (NIHSS ≤5) eligible for DAPT, we excluded patients with atrial fibrillation, anticoagulant use, prior major bleeding, or unknown stroke severity. FINDINGS: We identified 10,053 potential DAPT-candidates (mean age 72.6 years, 45.2% female, 16.4% with TIA). With advancing age, most vascular risk factors increased. Antiplatelet treatment increased from 31.9% before the event to 95.5% after discharge. Within 1 year following index event, the proportion of patients with ≥1 re-admission increased with age (29.2% in 40-64 year-olds; 47.2% in 85-100 year-olds). All-cause death per 100 person-years was 6.9 (95% CI 6.4-7.4) within 1 year, and highest in the first 30 days (15.2; 95% CI 12.8-18.2). For each year of increased age, the risk of death increased with 3.5% (p = 0.128) in patients 40-64 years and with 11.8% (p < 0.001) in those ≥85 years. CONCLUSIONS: While in theory representing a subset of patients with mild injury, our observational study highlights substantial use of health-care resources and high mortality rates among patients with high-risk TIA or minor ischemic stroke assumed eligible for DAPT.

Extended dual antiplatelet therapy with ticagrelor 60 mg in patients with prior myocardial infarction: The design of ALETHEIA, a multi-country observational study.

INTRODUCTION: Clinical guidelines recommend extended treatment with dual antiplatelet therapy (DAPT) with ticagrelor 60 mg (twice daily) beyond 12 months in high-risk patients with a history of myocardial infarction (MI) who have previously tolerated DAPT and are not at heightened bleeding risk. However, evidence on patterns of use and associated clinical outcomes in routine clinical practice is limited. METHODS: ALETHEIA is an observational, multi-country study, designed to describe characteristics, treatment persistence, and bleeding and cardiovascular (CV) outcomes in post-MI patients who initiate ticagrelor 60 mg in routine clinical practice (NCT04568083). The study will include electronic health data in the United States (US; Medicare, commercial claims) and Europe (Sweden, Italy, United Kingdom, Germany). Characteristics will be described among patients with and without ticagrelor 60 mg ≥1 year post-MI. Assuming an a priori threshold of 5000 person-years on-treatment is met, to ensure sufficient precision, clinical outcomes (bleeding and CV events) among patients treated with ticagrelor 60 mg will be assessed. Risk factors for clinical outcomes and treatment discontinuation will be assessed in patients with ticagrelor 60 mg and meta-analysis used to combine estimates across databases. Cohort selection will initiate from the ticagrelor 60 mg US and European approval dates and end February 2020. An estimated total of 7250 patients prescribed ticagrelor 60 mg are expected to be included. DISCUSSION: An increased understanding of patterns of ticagrelor 60 mg use and associated clinical outcomes among high-risk patients with a prior MI is needed. The a priori specified stepwise approach adapted in this observational study is expected to generate useful evidence for clinical decision-making and treatment optimization.