Spirometric alterations in patients with reduced renal function.

Spirometric parameters were measured in 49 patients with reduced renal function. The patients were divided according to their glomerular filtration rate (GFR) into two groups: (A) GFR < 0.2 ml s-1-end stage renal failure; (B) GFR > or = 0.2 ml s-1. FEV1 and FEF25-75 were significantly lower in the end-stage renal failure group of patients. 80% of the patients with GFR < 0.2 ml s-1 and 31% of the patients with GFR > or = 0.2 ml s-1 had spirometric evidence of small airways dysfunction. In multiple stepwise regression analysis with ventilatory parameters as dependent variables and renal function, total protein, urea, creatinine, sodium, and hemoglobin levels, proteinuria, diuresis, and history of left ventricular failure as independent variables only GFR and total protein correlated significantly with FEV1 and FEF25. In conclusion, our study demonstrates that impairment of spirometric function in patients with renal insufficiency is continual, with reduction of GFR, and thus small airways dysfunction may be expected not only in patients with end-stage renal failure, but also in those with moderate GFR reduction.