Patients with Biopsy-proven Nephrosclerosis and Moderately Impaired Renal Function Have a Higher Risk for Cardiovascular Disease: 15 Years' Experience in a Single, Kidney Disease Center

Background: Nephrosclerosis progresses slowly to end-stage renal disease (ESRD) in only a small percentage of patients. However, because hypertension and nephrosclerosis are normally found simultaneously, nephrosclerosis is a risk factor for cardiovascular disease (CVD). In turn, the onset of CVD may progress to further renal impairment.

Aim: To evaluate clinical outcomes and the association between nephrosclerosis and CVD in the long term.

Design: Prospective study

Methods: We prospectively assessed 35 patients (male/female: 19/16) with nephrosclerosis aged >30 years at disease onset, attending the Kidney Disease Center, Saitama Medical University, in a single teaching hospital center between 1995 and 2014. Nephrosclerosis was diagnosed in accordance with the criteria outlined in the World Health Organization (WHO) monograph of renal diseases. All patients were followed by means of registries for 10 years to record subsequent events, if any.

Outcomes: The primary study outcome was correlating the occurrence of CVD, defined as a composite of cardiovascular deaths, nonfatal and fatal myocardial infarction, and stroke, with the development of ESRD or death.

Results: The mean age of patients at the time of biopsy was 54.8 ± 12.7 years (range 33-72 years). Of these patients, seven were affected by nonfatal CVD and two died due to CVD. Only one patient developed ESRD during the follow-up period. Using Kaplan-Meier analysis, risk factors for the primary study outcome were estimated to include an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m(2), systolic blood pressure > 130 mmHg and proteinuria > 1 g/g creatinine. Univariate analysis was used for the assessment of the relative risk for the primary study endpoint of several covariates: age, systolic blood pressure, eGFR and proteinuria at time of renal biopsy. eGFR was found to be the strongest factor determining an event-free period [relative risk (RR) =1.931, p = 0.014].

Conclusions: Patients with nephrosclerosis are at high risk of CVD when they have moderately advanced renal impairment.