Background: The associations between bone loss and other metabolic complications of HAART are not well defined.

 

Methods:  We performed a cross sectional analysis at our HIV clinic enrolling 3 groups of subjects: patients on PIs, patients on NNRTIs, and HIV negative control subjects.  Bone mineral density (BMD) was assessed by DXA at the spine, total hip, femoral neck, total forearm, and ultradistal radius.  Each subject had a fasting lipid panel, a 2-hour glucose tolerance test, and regional body composition assessment by DXA.  c² analysis compared groups based on degree of bone loss. Between-group differences of continuous variables were assessed by ANOVA. Metabolic parameters were correlated by grouped univariate regression with T-score at each of the 5 sites.

 

Results: 25 patients on PIs, 26 on NNRTIs, and 22 HIV-negative controls were assessed (mean age 40 years, 83% male, mean CD4 689 cells/mm³, mean duration of therapy 33 months).  Osteoporosis (T-score< -2.5) was seen in 16% of PI group and was absent in NNRTI and control group. Osteopenia (T-score<-1) was seen in 52% of PI patients, 58% of NNRTI patients, and 32% of controls (c² =12.92, p=0.012).  Lower HDL and higher LDL cholesterol was seen among the PI group (ANOVA, p<0.01), but no significant correlations were seen between lipid fractions and reduced BMD. After adjusting for duration of HAART, no significant differences between groups were observed in measures of central adiposity or peripheral wasting, although in the PI group central adiposity was associated with decreased T-score in the forearm (r=0.55, p=0.019), ultradistal radius (r=0.635, p=0.003), and femoral neck (r=0.451, p for trend= 0.082).  While the prevalence of impaired glucose tolerance (2 hour glucose> 140) did not differ between the groups, impaired fasting glucose (> 110 mg/dL) was more common among the PI group (20% vs 3.8% NNRTI vs 0% control)( c² =7.229, p=0.027). In addition, reduced BMD at the forearm (p=0.003), ultradistal radius (p=0.006), and spine (p for trend=0.09) was associated with fasting glucose levels in the PI group, but not the NNTI or control groups.  Significant correlations in the PI group between BMD and insulin resistance were also noted. Associations were independent of duration of therapy or central adiposity.

 

Conclusions: Bone loss is prevalent among HIV patients on HAART.  Protease inhibitor use is associated with a high prevalence of impaired fasting glucose, which correlates with reduced bone mineral density at multiple sites independent of central adiposity.  Patients on protease inhibitors with glucose abnormalities may be at increased risk of  bone loss and may benefit from DXA screening.