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.