Ambulatory care for HIV-infected patients: differences in outcomes between hospital-based units and private practices: analysis of the RESINA cohort.

Background: The efficacy of highly active antiretroviral therapy (HAART) in the treatment of HIV infection is influenced by factors such as potency of applied drugs, adherence of the patient, and resistance-associated mutations. Up to now, there is insufficient data on the impact of the therapeutic setting.

Methods: Since 2001, the prospective multicenter RESINA study has examined the epidemiology of transmitted HIV drug resistance in Nordrhein-Westfalen, the largest federal state of Germany by population. Characteristics of patients treated in hospital-based outpatient units were compared to those of patients treated in medical practices. Longitudinal data of all participants are being followed in a cohort study.

Results: Overall, 1,591 patients were enrolled between 2001 and 2009 with follow-up until the end of 2010. Of these, 1,099 cases were treated in hospital-based units and 492 in private practices. Significant differences were found with respect to baseline characteristics. A higher rate of patients with advanced disease and non-European nationality were cared for in hospital units. Patients in medical practices were predominantly Caucasian men who have sex with men (MSM) harboring HIV-1 subtype B, with lower CDC stage and higher CD4 cell count. Median viral load was 68,828 c/mL in hospital-based units and 100,000 c/mL in private practices (P = 0.041). Only median age and rate of transmitted drug resistance were not significantly different. After 48 weeks, 81.9% of patients in hospital units and 85.9% in private practices had a viral load below the limit of detection (P = 0.12). A similar result was seen after 96 weeks (P = 0.54). Although the baseline CD4 cell count was different (189.5/μL in hospital units and 246.5/μL in private practices, P <0.001), a consistent and almost identical increase was determined in both groups.

Conclusions: The RESINA study covers a large HIV-infected patient cohort cared for in specialized facilities in Germany. Despite significant differences of patients' baseline characteristics in hospital-based units compared to medical practices, we could not find significant differences in treatment outcome up to 2 years after the initiation of HAART.