AIDS-Associated Nephropathy/epidemiology; Glomerulonephritis/epidemiology; HIV Infections/epidemiology; HIV-1/pathogenicity; AIDS-Associated Nephropathy/diagnosis; AIDS-Associated Nephropathy/immunology; AIDS-Associated Nephropathy/virology; Adolescent; Black or African American/statistics & numerical data; Age Factors; Biopsy; CD4 Lymphocyte Count; Chi-Square Distribution; Child; Child, Preschool; Chronic Disease; Female; Glomerulonephritis/diagnosis; Glomerulonephritis/immunology; Glomerulonephritis/virology; HIV Infections/diagnosis; HIV Infections/immunology; HIV Infections/virology; HIV-1/growth & development; Humans; Incidence; Infant; Infant, Newborn; Linear Models; Male; Multicenter Studies as Topic; Multivariate Analysis; Puerto Rico/epidemiology; Retrospective Studies; Risk Assessment; Risk Factors; Surveys and Questionnaires; Time Factors; United States/epidemiology; Viral Load; Virus Replication