title: Factors related to changes in CD4+ T-cell counts over time in patients living with HIV/AIDS: a multilevel analysis.
abstract: BACKGROUND
  The measurement of CD4+ T-cell (CD4) counts is a strong predictor of progression to AIDS and a means of monitoring antiviral therapy (ART). The success or failure of controlling virus levels in untreated patients or those taking ART may be associated with treatment adherence, habits, correlated infections unrelated to HIV, cancer, immunosuppressive drugs; as well as socio-economic and psychosocial aspects and access to healthcare. The aim of the present study was to identify, using a multilevel model, the factors related to the variations of CD4 counts over time, in patients living with HIV.
  
  
  METHODS
  A cohort study was conducted with patients living with HIV, selected from July 2007 to December 2010. Patients were monitored from records of their first CD4 count after being diagnosed with HIV. A multilevel model with 3 levels of aggregation was applied to analyze the associations of predictor variables and the behavior of CD4 over time.
  
  
  RESULTS
  A total of 1870 patients were enrolled. The mean number of CD4 at the beginning of the cohort was 393.1 cells/mm³, and there was a mean increase of 1.529 cells/mm³ per month. Patient's age, smoking, use of illicit drugs, hospital treatment, changing doctors and the use of ART, were factors that affected the kinetics of the CD4 count during the follow-up period.
  
  
  CONCLUSIONS
  The results of this study indicated increased levels of CD4 over time in a cohort of patients living with HIV/AIDS and identified factors that may influence this increase and are liable to intervention.
authors: Federal University of Pernambuco, Department of Tropical Medicine, Recife, Pernambuco, Brazil ; State University of Pernambuco, School of Medical Sciences,Oswaldo Cruz University Hospital, Recife, Pernambuco, Brazil.
authors: Ulisses Ramos
authors: UR
authors: Montarroyos
authors: State University of Pernambuco, School of Medical Sciences,Oswaldo Cruz University Hospital, Recife, Pernambuco, Brazil.
authors: Demócrito Barros
authors: DB
authors: Miranda-Filho
authors: Departament of Statistics, Federal University of Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
authors: Cibele Comini
authors: CC
authors: César
authors: Department of Public Health, Research Center Aggeu Magalhães, Osvaldo Cruz Fundation, Recife, Pernambuco, Brazil.
authors: Wayner Vieira
authors: WV
authors: Souza
authors: Federal University of Pernambuco, Department of Tropical Medicine, Recife, Pernambuco, Brazil.
authors: Heloisa Ramos
authors: HR
authors: Lacerda
authors: Department of Public Health, Research Center Aggeu Magalhães, Osvaldo Cruz Fundation, Recife, Pernambuco, Brazil.
authors: Maria de Fátima Pessoa Militão
authors: Mde F
authors: Albuquerque
authors: State University of Pernambuco, School of Medical Sciences,Oswaldo Cruz University Hospital, Recife, Pernambuco, Brazil.
authors: Mariana Freitas
authors: MF
authors: Aguiar
authors: Federal University of Pernambuco, Department of Tropical Medicine, Recife, Pernambuco, Brazil ; State University of Pernambuco, School of Medical Sciences,Oswaldo Cruz University Hospital, Recife, Pernambuco, Brazil.
authors: Ricardo Arraes de Alencar
authors: RA
authors: Ximenes
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000097:blood* / Q000188:drug therapy* / Q000276:immunology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic