Renal arteriosclerosis in kidney biopsies associated with higher 10-year atherosclerotic cardiovascular disease in lupus nephritis.

OBJECTIVE

Patients with lupus nephritis (LN), including those below age 50, face significantly higher risk of atherosclerotic cardiovascular disease (ASCVD) vs peers. This highlights the need for identifying specific ASCVD risk factors in LN. Renal arteriosclerosis in kidney biopsies (subclinical arteriosclerosis) may be able to predict future clinical ASCVD events. However, renal arteriosclerosis is under-reported in LN biopsies and is not taken into consideration when ASCVD risk is calculated. Therefore, we aimed to systematically grade renal arteriosclerosis in kidney biopsies at LN diagnosis and examined associations with 10-year and 20-year ASCVD occurrence.

METHODS

Adults with biopsy-proven LN were included. Clinical ASCVD, including fatal and non-fatal events, were adjudicated. Utilizing standard Banff grading criteria, all biopsies at LN diagnosis were re-read to grade renal arteriosclerosis. Covariables (e.g. socio-demographics, comorbidities, med exposure) were abstracted. Using Cox models, factors (including renal arteriosclerosis) associated with 10-year and 20-year clinical ASCVD were examined.

RESULTS

Among 209 patients, 36 and 49 clinical ASCVD occurred within 10 and 20 years. Renal arteriosclerosis (>25%) was associated with 3× higher 10-year ASCVD. High area deprivation index (>80) and longer angiotensin converting enzyme inhibitor (ACEi) exposure were associated with 4× higher and 0.65× lower ASCVD occurrence. Adding renal arteriosclerosis >25% improved model performance for 10-year ASCVD risk estimation from 65% to 80%. Similar associations were seen with 20-year ASCVD.

CONCLUSION

Renal arteriosclerosis >25%, area deprivation and ACEi exposure could inform ASCVD risk stratification in LN. Prospective studies should validate findings and inform clinical use.