[Prevalence of kidney disease in HIV-infected patients in Japan--A single center study].

Background: Kidney disease is a significant cause of morbidity and mortality among persons infected with the human immunodeficiency virus (HIV). However, epidemiologic and clinical variables regarding kidney disease have not been determined among HIV-infected patients in Japan.
Patients and Methods: A cross-sectional study of 788 HIV-infected outpatients including 706 men was conducted in 2009. The patient's mean age and CD4+ T cell count were 46.2 +/-11.8 years and 418 +/- 202/microL, respectively. Of them, 677 patients (86%) had an undetectable HIV-RNA level (<50 copies/mL). Random urine and blood samples were collected to study the coexistence of chronic kidney disease (CKD). In addition, serum cystatin C was measured since it is considered to be an alternative marker of early kidney dysfunction in the HIV population. The estimated glomerular filtration rate (eGFR) based on serum creatinine was calculated using the 3-variable equation, proposed by the Japanese Society of Nephrology [eGFR (mL/ min/1.73m2) = 194 x Serum creatinine (-1.094) x Age (-0.287 x 0.739 (if female)]. CKD stages were classified based on the National Kidney Foundation guidelines.
Results: The prevalence of CKD and that of CKD > or = stage 3 was 14.9% and 9.4%, respectively. The pro-portion of each stage was as follows: stage 1, 15 patients (1.9%); stage 2, 28 patients (3.6%); stage 3, 66 patients (8.4%); stage 4, 1 patient (0.1%); stage 5, 1 patient (0.1%); and stage 5D, 6 patients (0.8%). Elevation of serum cystatin C (> or = 0.9 mg/L) was found in 23.3%. Comorbidities such as hypertension and diabetes were found in 55.4% and 27.0% in patients with CKD > or = stage 3, respectively. Urinalysis showed 71 patients (9.1%) with proteinuria and 44 patients (5.6%) with hematuria.
Conclusion: CKD has become an important comorbidity for HIV-infected patients in Japan, a point that should be given more emphasis from public health perspective.