The spectrum of renal abnormalities in patients with psoriasis

Kidney involvement secondary to psoriasis is a controversial issue. In this study, we evaluated the prevalence of urinary abnormalities in patients with psoriasis.

Forty-five psoriasis patients (28 women, 17 men, mean age 44 ± 14 years) and 45 age- and gender-matched control subjects without hypertension or diabetes were enrolled in the study. Psoriasis area and severity index (PASI) was used to assess the severity of psoriasis. Urinalysis by dipstick and microscopic evaluation and 24-h proteinuria and albuminuria were measured in all patients and controls. Pathologic albuminuria was defined as albumin excretion of more than 30 mg/24 h. Renal biopsy was performed in psoriasis patients with urinary abnormalities.

Patients with psoriasis and controls were not significantly different with respect to the prevalence of abnormal urinalysis (17.7% vs. 13.3%, P = 0.56), mean 24-h proteinuria (145 ± 66 mg/24 h vs. 141 ± 71 mg/24 h, P = 0.54), and albuminuria (21 ± 34 mg/24 h vs. 8 ± 9 mg/24 h, P = 0.31). However, patients with psoriasis had an increased prevalence of pathologic albuminuria compared with controls (24% vs. 2%, P = 0.005). PASI scores in psoriasis patients correlated significantly with 24-h albuminuria (r = 0.458, P = 0.007). Of the eight patients with psoriasis who had urinary abnormalities, four underwent renal biopsy. Two of them had biopsy-proven glomerulonephritis: mesangial proliferative glomerulonephritis in one and IgA nephropathy in the other.

The presence of abnormal urinalysis was not more common in patients with psoriasis than in controls. However, the increased prevalence of pathologic albuminuria and its positive correlation with psoriasis severity may suggest subclinical glomerular dysfunction in these patients.