The cIMT was measured in 476 HIV-infected individuals without clinical evidence of CVD. The demographics of the slightly smaller subset (n = 471) with cystatin C measurements are shown in table . The mean age of the study participants was 48 years. Females comprised 31% of the study sample. The overall median values for eGFRCys and eGFRCr among study participants were 88 ml/min/1.73 m2 (interquartile range (IQR), 72, 108) and 94 ml/min/1.73 m2 (IQR, 79, 113), respectively. Of the 369 patients with urine albumin measured, the prevalence of albuminuria was 34%.
Demographic and clinical characteristics of participants by quartile of eGFRCys
Participants with lower eGFRCys
were older and more often men compared to those with higher eGFRCys
. There were no statistically significant differences in race across quartiles of eGFRCys
. Participants in the lower quartiles of eGFRCys
had higher prevalence of smoking, lower HDL levels, and higher systolic blood pressures. The prevalence of diabetes appeared higher in the lower quartiles of eGFRCys
, but did not reach statistical significance (p = 0.06). Insulin levels were modestly higher in patients with lower eGFRCys
. There were no statistically significant differences in the use of lipid-lowering medications, angiotensin-converting enzyme inhibitors, or angiotensin receptor blockers across quartiles of eGFRCys
. As previously reported [8
], patients with lower eGFRCys
had lower CD4 lymphocyte counts, higher prevalence of HIV viremia, longer duration of HIV infection, and higher rates of coinfection with HCV. As anticipated, lower eGFRCys
was strongly associated with lower eGFRCr
and higher prevalence of albuminuria.
Overall mean values of common and internal cIMT were 0.86 ± 0.16 and 1.15 ± 0.49 mm, respectively. In the unadjusted analysis (fig. ), patients in the lower two quartiles of eGFRCys had a significantly higher common cIMT compared to patients in the highest eGFRCys quartile (mean common cIMT 0.88 ± 0.15 and 0.89 ± 0.16 mm, respectively, in quartiles 1 and 2, compared to 0.83 ± 0.16 mm in quartile 4, p < 0.05). However, this association was attenuated by demographic factors alone (age, gender, and race). Multivariate adjustment, which also included traditional CVD risk factors, HIV-related factors, and body composition, had little further effect. Similarly (fig. ), there was a strong unadjusted association between eGFRCys and internal cIMT (mean internal cIMT 1.25 ± 0.56 and 1.21 ± 0.52 mm, respectively, in quartiles 1 and 2, compared to 1.04 ± 0.39 mm in quartile 4, p < 0.01). This association was also attenuated after adjustment for demographic factors, and little association was present after full multivariate adjustment.
In table , we display the multivariable linear regression analyses comparing eGFRCys, eGFRCr, and albuminuria with common and internal cIMT. Both eGFRCys and eGFRCr were negatively associated with common and internal cIMT in the unadjusted analyses. However, the associations of eGFRCys and eGFRCr with common and internal cIMT were largely attenuated after adjustment for demographic factors alone. The presence of albuminuria was associated with an increase in common cIMT of 0.021 mm in the unadjusted analysis, but the association did not reach statistical significance (p = 0.14), and was completely attenuated after demographic adjustment. Albuminuria showed little association with internal cIMT. Results were similar in a sensitivity analysis that used inverse probability weighting to mitigate selection bias (supplemental table ).