Tubular Proteinuria and Glomerular Filtration 6 Years after Puumala Hantavirus-Induced Acute Interstitial Nephritis

Abstract

Background/Aims: We previously found increased urinary protein excretion, glomerular filtration rate (GFR) and blood pressure in a retrospective analysis of patients with previous nephropathia epidemica (NE). Here, we evaluated the long-term outcome after NE in a prospectively recruited patient group. Methods: Proteinuria, GFR and ambulatory 24-hour blood pressure were assessed 4–7 years (mean 6) after acute NE in 37 patients, and these values were compared to those from 38 seronegative controls. Results: Six years after NE, the prevalence of elevated urinary α₁-microglobulin excretion was higher in the patients than controls (9/35 vs. 1/38; p = 0.005). The patients also had higher urinary protein excretion (0.17 ± 0.05 vs. 0.14 ± 0.04 g/day; p = 0.006), GFR (119 ± 19 vs. 109 ± 14 ml/min/1.73 m²; p = 0.016) and mean systolic (123 ± 11 vs. 117 ± 9 mm Hg; p = 0.012), nighttime systolic (109 ± 11 vs. 100 ± 9 mm Hg; p = 0.001) and nighttime diastolic blood pressure (70 ± 7 vs. 66 ± 7 mm Hg; p = 0.035) than the controls. Conclusions: These results confirm our previous findings of a higher prevalence of tubular proteinuria and increased urinary protein excretion, GFR and systolic blood pressure 6 years after acute NE.