Daily Cardiology Research Analysis
Three high-impact cardiology studies stand out today: a large meta-analysis shows SGLT2 inhibitors slow CKD progression across the full spectrum of kidney function and albuminuria, supporting broader use in patients with diabetes, CKD, or heart failure. A multicenter RCT in JAMA finds liberal postoperative transfusion does not improve major ischemic outcomes vs a restrictive strategy in high cardiac-risk surgical patients. A UK Biobank cohort indicates guideline-level physical activity is benefi
Summary
Three high-impact cardiology studies stand out today: a large meta-analysis shows SGLT2 inhibitors slow CKD progression across the full spectrum of kidney function and albuminuria, supporting broader use in patients with diabetes, CKD, or heart failure. A multicenter RCT in JAMA finds liberal postoperative transfusion does not improve major ischemic outcomes vs a restrictive strategy in high cardiac-risk surgical patients. A UK Biobank cohort indicates guideline-level physical activity is beneficial and safe for genotype-positive, phenotype-negative cardiomyopathy variant carriers.
Research Themes
- Cardio-renal therapeutics and outcomes across CKD spectrum
- Perioperative transfusion thresholds in high cardiac-risk patients
- Exercise safety and benefits in genotype-positive, phenotype-negative cardiomyopathy
Selected Articles
1. SGLT2 Inhibitors and Kidney Outcomes by Glomerular Filtration Rate and Albuminuria: A Meta-Analysis.
Across 10 randomized trials (n=70,361), SGLT2 inhibitors reduced CKD progression by 38% (HR 0.62) irrespective of baseline eGFR or albuminuria, including in stage 4 CKD and minimal albuminuria. They also attenuated annual eGFR decline and reduced kidney failure risk. These findings support routine SGLT2 use across the kidney function spectrum in patients with type 2 diabetes, CKD, or heart failure.
Impact: This comprehensive meta-analysis provides decisive, generalizable evidence that SGLT2 inhibitors protect kidney function across diverse CKD phenotypes, filling key evidence gaps (stage 4 CKD, low albuminuria).
Clinical Implications: Initiate SGLT2 inhibitors broadly for patients with T2D, CKD, or heart failure to slow CKD progression, even with eGFR <30 mL/min/1.73 m2 or minimal albuminuria, unless contraindicated. Monitor eGFR trajectory but expect slower decline.
Key Findings
- CKD progression reduced with SGLT2 inhibitors (HR 0.62; 95% CI 0.57-0.68).
- Benefit consistent across eGFR strata including <30 mL/min/1.73 m2 (P for trend=.16).
- Benefit consistent across albuminuria strata including ≤30 mg/g (P for trend=.49).
- Annual eGFR decline attenuated and kidney failure risk reduced (HR 0.66).
Methodological Strengths
- Pooled randomized, double-blind, placebo-controlled trials with large sample size (n=70,361).
- Predefined renal outcomes and consistent subgroup analyses across eGFR and UACR.
Limitations
- Heterogeneity in trial populations and follow-up durations may influence effect size estimates.
- Limited granularity for very advanced CKD subgroups beyond trial inclusion criteria.
Future Directions: Head-to-head comparisons within advanced CKD and low-albuminuria phenotypes; implementation studies to optimize uptake and address safety in very low eGFR.
IMPORTANCE: Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce chronic kidney disease (CKD) progression in individuals with type 2 diabetes, CKD, or heart failure. However, their effects in those with stage 4 CKD or little to no albuminuria remain uncertain. OBJECTIVE: To assess whether estimated glomerular filtration rate (eGFR) or degree of albuminuria, measured by urinary albumin to creatinine ratio (UACR), modifies the effects of SGLT2 inhibitors on kidney outcomes. DATA SOURCES: SGLT2 inhibitor trials participating in the SGLT2 Inhibitor Meta-Analysis Cardio-Renal Trialists' Consortium (SMART-C). STUDY SELECTION: Randomized, double-blind, placebo-controlled trials within SMART-C evaluating an SGLT2 inhibitor with label indications for reducing CKD progression including at least 500 participants in each group with at least 6 months of follow-up. DATA EXTRACTION AND SYNTHESIS: Treatment effects in individual trials were pooled using inverse variance-weighted meta-analysis. MAIN OUTCOMES AND MEASURES: CKD progression, defined as kidney failure, at least 50% reduction in eGFR, or death due to kidney failure. Other outcomes included annual rate of eGFR decline and kidney failure. RESULTS: Among 70 361 participants (mean [SD] age, 64.8 [8.7] years; 24 595 [35.0%] females) in 10 randomized trials, 2314 (3.3%) experienced CKD progression and 988 (1.4%) reached kidney failure. SGLT2 inhibitors reduced the risk of CKD progression (25.4 vs 40.3 events per 1000 patient-years; hazard ratio [HR], 0.62 [95% CI, 0.57-0.68]), irrespective of baseline eGFR (HR of 0.61 [95% CI, 0.52-0.71] for eGFR ≥60 mL/min/1.73 m2; 0.57 [95% CI, 0.47-0.70] for eGFR of 45 to <60 mL/min/1.73 m2; 0.64 [95% CI, 0.54-0.75] for eGFR of 30 to <45 mL/min/1.73 m2; and 0.71 [95% CI, 0.60-0.83] for eGFR <30 mL/min/1.73 m2; P for trend = .16) and baseline albuminuria (HR of 0.58 [95% CI, 0.44-0.76] for albuminuria ≤30 mg/g; 0.74 [95% CI, 0.57-0.96] for >30-300 mg/g; and 0.57 [95% CI, 0.52-0.64] for more than 300 mg/g; P for trend = .49). Although the magnitude of protection varied, SGLT2 inhibitors reduced the annual rate of eGFR decline across all eGFR and UACR subgroups, including when participants with and without diabetes were analyzed separately. SGLT2 inhibitors also reduced the risk of kidney failure alone (HR, 0.66 [95% CI, 0.58-0.75]). CONCLUSIONS AND RELEVANCE: In this meta-analysis, SGLT2 inhibitors were found to lower the risk of CKD progression regardless of baseline eGFR or albuminuria, including in patients with stage 4 CKD or minimal albuminuria, supporting their routine use to improve kidney outcomes across the full spectrum of kidney function among patients with type 2 diabetes, CKD, or heart failure.
2. Liberal or Restrictive Postoperative Transfusion in Patients at High Cardiac Risk: The TOP Randomized Clinical Trial.
In 1424 high cardiac-risk veterans after major surgery, a liberal transfusion trigger (<10 g/dL) did not reduce 90-day death or major ischemic events versus a restrictive trigger (<7 g/dL). A secondary composite of non-MI cardiac complications (arrhythmias, heart failure, nonfatal cardiac arrest) was lower with liberal transfusion.
Impact: This large, pragmatic RCT directly tests transfusion thresholds in a high-risk surgical population and supports the safety of restrictive strategies for major ischemic outcomes.
Clinical Implications: Continue to favor restrictive postoperative transfusion thresholds (Hb <7 g/dL) for high cardiac-risk surgical patients for major ischemic outcomes; consider individualized decisions for arrhythmia/HF risk given secondary findings.
Key Findings
- Primary composite (death, MI, revascularization, AKI, ischemic stroke) similar between strategies (9.1% vs 10.1%; RR 0.90; 95% CI 0.65–1.24).
- Non-MI cardiac complications lower with liberal strategy (5.9% vs 9.9%; RR 0.59; 99% CI 0.36–0.98).
- Mean Hb difference of ~2.0 g/dL achieved by day 5 between strategies.
Methodological Strengths
- Multicenter, randomized, single-blind superiority trial with intention-to-treat analysis.
- Clear intervention thresholds producing meaningful hemoglobin separation.
Limitations
- Predominantly male veteran population limits generalizability.
- Trial not powered for secondary outcomes; findings on cardiac complications are exploratory.
Future Directions: Assess thresholds in broader, more diverse surgical populations and evaluate targeted strategies for patients at high risk of arrhythmia or heart failure.
IMPORTANCE: Postoperative red blood cell transfusion guidelines recommend transfusion for hemoglobin levels less than 7 g/dL. However, the safety of this strategy in patients at high risk of cardiac events undergoing major operations remains unclear. OBJECTIVE: To evaluate the risk of death or major ischemic events within 90 days after a liberal transfusion strategy compared with a restrictive transfusion strategy in patients at high risk of cardiac events who had undergone major vascular or general surgery operations and developed postoperative anemia. DESIGN, SETTING, AND PARTICIPANTS: This parallel, single-blind, randomized clinical superiority trial included 1428 veterans (≥18 y) at high cardiac risk undergoing major vascular or general surgery operations. Participants were enrolled from February 2018 to March 2023 across 16 Veterans Affairs Medical Centers in the US. INTERVENTIONS: Seven hundred fourteen participants with postoperative hemoglobin less than 10 g/dL were randomized to a liberal strategy (transfusion trigger at hemoglobin level <10 g/dL) and 714 to a restrictive strategy (transfusion trigger at hemoglobin <7 g/dL). MAIN OUTCOMES AND MEASURES: The primary end point was a composite of all-cause death, myocardial infarction, coronary revascularization, acute kidney failure, or ischemic stroke within 90 days after randomization. Secondary end points included a composite of cardiac complications other than myocardial infarction (arrhythmias, heart failure, and nonfatal cardiac arrest). RESULTS: Of the 1424 analyzed veterans (mean age, 69.9 [SD, 7.9] years; 1393 male [97.8%]; 268 Black [18.8%]; 48 Hispanic [4.1%]; 1071 White [75.2%]), 1297 (91.1%) underwent vascular surgical procedures. The mean hemoglobin difference between transfusion strategies was 2.0 g/dL on day 5 after randomization. The primary outcome rate in the liberal group was 9.1% (61 of 670) compared with 10.1% (71 of 700) in the restrictive group (relative risk, 0.90; 95% CI, 0.65-1.24). The secondary end point of cardiac complications without myocardial infarction, which was 1 of 5 secondary end points, occurred in 5.9% (38 of 647) of patients in the liberal group and 9.9% (67 of 678) of patients in the restrictive group (relative risk, 0.59; 99% CI, 0.36-0.98). CONCLUSIONS AND RELEVANCE: After major vascular or general surgery operations among patients at high risk of a cardiac event, a liberal transfusion strategy did not reduce 90-day death or major ischemic outcome rates compared with a restrictive strategy. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03229941.
3. Physical Activity and Cardiovascular Outcomes in Phenotype-Negative Cardiomyopathy Variant Carriers.
Among 84,699 adults with accelerometer data and WGS, greater MVPA was associated with lower AF, HF, MI, and stroke risk in genotype-positive, phenotype-negative carriers, with lowest risk around 100–400 minutes/week. MVPA did not increase malignant ventricular arrhythmias and was linked to lower incident cardiomyopathy risk, with similar cardiac remodeling patterns vs noncarriers.
Impact: This study addresses a major counseling uncertainty by providing objective, accelerometer-based evidence that guideline-level activity is beneficial and not proarrhythmic in G+P- carriers.
Clinical Implications: Clinicians can endorse guideline-level MVPA (approximately 100–400 min/week) for G+P- carriers without increasing malignant VA risk, while monitoring as per genotype-specific recommendations.
Key Findings
- In G+P- carriers, higher MVPA associated with lower AF (HR 0.68), HF (HR 0.58), MI (HR 0.49), and stroke (HR 0.35).
- Optimal risk reduction generally observed at 100–400 min/week of MVPA.
- No increase in malignant ventricular arrhythmias; HR ~0.98 at 400 min/week vs 0.
- Lower incident cardiomyopathy risk at optimal MVPA (HR 0.03; 95% CI 0.00–0.98).
Methodological Strengths
- Large prospective cohort with objective accelerometer-based activity and WGS-defined genotype.
- CMR substudies enabling structural-functional correlation and remodeling assessment.
Limitations
- Observational design with potential residual confounding; accelerometer measured only 1 week at baseline.
- Limited precision for arrhythmogenic right ventricular cardiomyopathy variant subgroup estimates.
Future Directions: Interventional trials testing tailored exercise prescriptions by genotype and longitudinal device-based arrhythmia monitoring in G+P- populations.
IMPORTANCE: Exercise may lead to disease progression and higher risk of sudden death in individuals with genetic cardiomyopathies, but the effects of exercise among individuals carrying a cardiomyopathy-associated variant without clinical manifestations (G+P-) are unclear. OBJECTIVE: To examine whether the effects of moderate to vigorous physical activity (MVPA) on cardiovascular (CV) outcomes, cardiac structure and function, and risk of developing overt cardiomyopathy and malignant ventricular arrhythmias (VAs) vary by G+P- status. DESIGN, SETTING, AND PARTICIPANTS: UK Biobank participants with whole-genome sequencing providing 1 week of accelerometer-based physical activity data and without prevalent heart failure (HF), atrial fibrillation (AF), cardiomyopathy, VAs, or implantable cardioverter-defibrillators were included in this cohort study. The study was conducted at 22 assessment centers throughout the UK from February 2013 to December 2015 with a median follow-up of 8 years. Data were analyzed from March 2024 to June 2025. EXPOSURE: Accelerometer-measured MVPA (minutes/week). MAIN OUTCOMES AND MEASURES: Associations were analyzed between MVPA volume and future incidence of adverse CV outcomes (AF, HF, myocardial infarction [MI], and stroke), cardiac magnetic resonance (CMR)-based measures of cardiac remodeling, and surrogates for clinical cardiomyopathy onset (cardiomyopathy and VA). Associations were compared between G+P- carriers and noncarriers. RESULTS: Among 84 699 individuals (mean [SD] age, 62 [8] years; 48 353 [57%] women; 3979 G+P- carriers), greater MVPA was associated with a lower risk of adverse CV outcomes over a median (IQR) 8.0 (7.5-8.5) years, irrespective of genotype. In multivariable models, higher MVPA was broadly associated with lower risk of incident CV disease in G+P- carriers (hazard ratio [HR] at optimal MVPA level vs zero [95% CI], AF: 0.68 [0.58-0.79]; HF: 0.58 [0.47-0.71]; MI: 0.49, [0.24-1.00]; stroke: 0.35 [0.12-0.99]). For G+P- carriers, MVPA in the range of 100 to 400 minutes per week was generally associated with lowest risk. Among individuals with CMR imaging, MVPA was associated with a similar pattern and extent of cardiac remodeling (eg, left ventricular dilation and left ventricular hypertrophy) in G+P- carriers vs noncarriers. Among G+P- carriers, higher MVPA was associated with lower risk of incident cardiomyopathy (HR at optimal MVPA vs 0, 0.03; 95% CI, 0.00-0.98) with no increase in risk of VA (eg, HR at 400 minutes of MVPA vs 0, 0.98; 95% CI, 0.83-1.14). Findings were generally consistent across variants associated with dilated cardiomyopathy, hypertrophic cardiomyopathy, or arrhythmogenic right ventricular cardiomyopathy, although precision of estimates for arrhythmogenic right ventricular cardiomyopathy were limited. CONCLUSIONS AND RELEVANCE: In this cohort study, MVPA within the general range of guideline-based recommendations was associated with lower risk of adverse CV outcomes and similar degrees of cardiac remodeling for G+P- carriers compared to noncarriers. Findings support the appropriateness of guideline-based MVPA recommendations for G+P- carriers.