Associations between Kidney Histopathologic Lesions and Incident Cardiovascular Disease in Adults with Chronic Kidney Disease

Importance: Histologic lesions in the kidney may reflect or contribute to systemic processes that may lead to adverse cardiovascular events. Objective: To assess the association between kidney histopathologic lesion severity and the risk of incident major adverse cardiovascular events (MACE). Design, Setting, and Participants: This prospective observational cohort study included participants without a history of myocardial infarction, stroke, or heart failure from the Boston Kidney Biopsy Cohort recruited from 2 academic medical centers in Boston, Massachusetts. Data were collected from September 2006 and November 2018, and data were analyzed from March to November 2021. Exposures: Semiquantitative severity scores for kidney histopathologic lesions adjudicated by 2 kidney pathologists, a modified kidney pathology chronicity score, and primary clinicopathologic diagnostic categories. Main Outcomes and Measures: The main outcome was the composite of death or incident MACE, which included myocardial infarction, stroke, and heart failure hospitalization. All cardiovascular events were independently adjudicated by 2 investigators. Cox proportional hazards models estimated associations of histopathologic lesions and scores with cardiovascular events adjusted for demographic characteristics, clinical risk factors, estimated glomerular filtration rate (eGFR), and proteinuria. Results: Of 597 included participants, 308 (51.6%) were women, and the mean (SD) age was 51 (17) years. The mean (SD) eGFR was 59 (37) mL/min per 1.73 m², and the median (IQR) urine protein to creatinine ratio was 1.54 (0.39-3.95). The most common primary clinicopathologic diagnoses were lupus nephritis, IgA nephropathy, and diabetic nephropathy. Over a median (IQR) of 5.5 (3.3-8.7) years of follow-up, the composite of death or incident MACE occurred in 126 participants (37 per 1000 person-years). Compared with the reference group of individuals with proliferative glomerulonephritis, the risk of death or incident MACE was highest in individuals with nonproliferative glomerulopathy (hazard ratio [HR], 2.61; 95% CI, 1.30-5.22; P =.002), diabetic nephropathy (HR, 3.56; 95% CI, 1.62-7.83; P =.002), and kidney vascular diseases (HR, 2.86; 95% CI, 1.51-5.41; P =.001) in fully adjusted models. The presence of mesangial expansion (HR, 2.98; 95% CI, 1.08-8.30; P =.04) and arteriolar sclerosis (HR, 1.68; 95% CI, 1.03-2.72; P =.04) were associated with an increased risk of death or MACE. Compared with minimal chronicity, greater chronicity was significantly associated with an increased risk of death or MACE (severe: HR, 2.50; 95% CI, 1.06-5.87; P =.04; moderate: HR, 1.66; 95% CI, 0.74-3.75; P =.22; mild: HR, 2.22; 95% CI, 1.01-4.89; P =.047) in fully adjusted models. Conclusions and Relevance: In this study, specific kidney histopathological findings were associated with increased risks of CVD events. These results provide potential insight into mechanisms of the heart-kidney relationship beyond those provided by eGFR and proteinuria..