Evaluation and Outcome of Proteinuria in Older and Younger Adults

Background. The spectrum of proteinuric renal disease in older adults remains incompletely defined. The purpose of the present study was to determine if differences exist in diagnostic approach, etiology, therapy, and outcome between older (>60 years) and younger (,60 years) patients referred for evaluation of proteinuria. Methods. We conducted a retrospective review of outpatient office charts in a 7-physician, hospital-based nephrology practice. Results. We identified 69 patients with at least 1 subsequent follow-up assessment after reviewing approximately 500 sequential charts. Forty-five were younger (mean 6 SD age, 38 6 2 years), and 24 were older (69 6 1 years). The degree of proteinuria at presentation was similar (4.5 6 0.7 vs 3.9 6 0.6 g/d, older vs younger, p 5 NS), but older patients had higher creatinine levels (1.7 6 0.2 vs 1.2 6 0.07 mg/dl, p , .01), lower creatinine clearances (64 6 7 vs 111 6 7 ml/ min., p , .05), and higher systolic blood pressure (164 6 8/88 6 2 vs 145 6 4/94 6 2 mm Hg, p , .01). Older patients were more likely to decline a renal biopsy (21% vs 7.6%, p , .01). The most common final renal diagnoses were immunoglobulin A nephropathy (31%), focal segmental glomerulosclerosis (24%), hypertension (13%), and membranous nephropathy (11%) in the younger patients, and membranous nephropathy (29%), hypertension (25%), diabetic nephropathy (17%), and minimal change disease (8%) in the older patients. Steroids were given to 17.7% of younger patients and 16.7% of older patients (p 5 NS). The percentage of patients with improvement, defined as a 50% reduction in proteinuria with stable or improved renal function, was similar among older and younger patients (33.3% vs 35.5%). However, older patients were more likely to develop progression of renal disease (33.3% vs 8.8%) and less likely to retain stable renal function (29.2% vs 53.3%). Conclusion. Significant differences exist in proteinuric renal disease between older and younger adults.