Neurological complications of HIV infection in pre-HAART and HAART era: a retrospective study

The introduction of highly active anti-retroviral therapy (HAART) led to a radical change in the natural history of HIV infection and of the associated neurological opportunistic infections. However, the mortality of central nervous system (CNS) complications and opportunistic infections is still high in untreated HIV-infected individuals or in patients unaware of their HIV infection. We describe the outcome of HIV-infected patients followed at a single center for AIDS-related neurological syndromes in the 16 years following the introduction of HAART, and compare the findings with those in patients admitted up to 1996. We have conducted a retrospective study of patients with HIV infection or AIDS (based on WHO criteria and classified according to the 1993 CDC criteria) admitted during 20 years (January 1992 to March 2012) to the Infectious Diseases Unit of the University of Verona for the presence of focal or widespread CNS lesion on neuroimaging. Clinical history, CD4 cell count, HIV-RNA level, neurological examination, imaging, cerebrospinal fluid examination and eventual cerebral biopsy results were reviewed as well as the final neurological diagnosis and the treatment. The survival time from the clinical onset of the neurologic syndrome to death was calculated for each patient who died. A statistical analysis was performed comparing data collected up to and after 1996, i.e., before and after HAART introduction. Among 1043 patients with HIV infection or AIDS admitted to the Infectious Diseases Unit of the University of Verona between January 1992 and March 2012, 114 had a CNS lesion. The following diseases were observed: neurotoxoplasmosis (NT), progressive multifocal leukoencephalopathy), primary central nervous system lymphoma (PCNSL), the severe form of HIV-associated neurocognitive disorder, cryptococcal encephalitis (CE) and lesions of undetermined origin. The follow-up period was 4 weeks to 72 months both in the pre-HAART and HAART era. Cerebral lesions were detected in 53/243 patients (21.8%) in the pre-HAART era and in 61/801 patients (7.6%) in the HAART era (p < 0.001). Most patients who developed a neurological complication in the HAART period (40/59, 67.8%) were untreated or did not know to be HIV-infected; in particular, 27.9% of patients with a CNS lesion in the HAART era were unaware of their HIV infection vs 13.2% in the pre-HAART era (p < 0.05). Some patients were not virologically suppressed (14/59, 23.7%) or were immunological non-responders (undetectable viral load, with CD4 count <200 cells/μL; 4/59, 6.8%). Other statistically significant data were the mean age at the onset of neurological complications (32.6 ± 5.4 years in the pre-HAART, 40.3 ± 9.5 in the HAART group, p < 0.001) and the mean CD4 cell count at the onset of illness (median of 38 cells/µL (2-215) in the pre-HAART, 77 cells/µL (2-752) in the HAART group; p < 0.001). In the HAART era a reduction of PCNSL and NT was observed. Our results, while confirming a decrease in the incidence of opportunistic infections of the CNS in the HAART era, show that late presentation of patients with HIV infection remains an important issue in our catchment area.