[Proteinuria in primary care]

Proteinuria is one of the main symptoms of renal impairment. It may manifest itself as a small amount of albumin in the urine (microalbuminuria) or as the nephrotic syndrome. Testing strips results should be considered as preliminary; a negative result does not exclude renal disease. At present, proteinuria is assessed as a total protein waste in the urine collected over 24 hours with up to 150 mg/day being considered a norm. Lately, the protein (albumin) to creatinine ratio in a sample of morning urine is being preferred (protein/creatinine ratio - PCR or albumin/creatinine ratio - ACR). More detailed nephrological examination should be performed if these reach pathological values (PCR > 15 mg/mmol a ACR > 3.5 mg/mmol). These assessments are not burdened by the same variability of values as with the 24-hour urine collection. A number of studies provided evidence on the role of proteinuria (as well as microalbuminuria) in accelerating a decline in glomerular filtration as well as its role as a risk factor of total and cardiovascular mortality. Therefore, this issue should receive appropriate attention and patients who are in a higher risk of renal impairment should be intentionally sought. These include diabetics, patients with heart disease, hypertension and patients with known personal or family history of renal disease. Only when a renal disease (and proteinuria is a clear symptom) is detected in time, targeted or symptomatic treatment can by initiated to slow down or even halt the disease progression to end stage renal disease. Despite this, more than 1/3 of patients entering chronic dialysis treatment have not been monitored. This significantly increases their morbidity and mortality, particularly within the first year of dialysis. General practitioners as well as internal medicine specialists, cardiologists and diabetologists play a fundamental role in screening of the high risk population.