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. 2014 Feb 11;9(2):e88591. doi: 10.1371/journal.pone.0088591

Figure 3. CSF NFL related to age and treatment effect.

Figure 3

Since CSF NFL increases with age, we analyzed the group differences with a linear mixed effects model with age as covariate. This implies a model with three parallel regression lines where the group differences correspond to the vertical distances between the regression lines. The group differences can be expressed as the corresponding age increase needed for an equivalent difference. The 95% prediction interval of CSF NFL levels of HIV-negative controls is demonstrated as dotted lines (Neg 95% PI). Concentrations of CSF NFL in neuroasymptomatic untreated HIV-infected subjects (No ART) were equivalent to those of HIV-negative subjects (negative) who were 18.5 years older (p<0.001). CSF NFL concentrations in the treated group (ART) were equivalent to those of HIV-negative subjects who were 3.9 years older (p<0.01).