Progress Realized: Trends in HIV-1 Viral Load and CD4 Cell Count in a Tertiary-Care Center from 1999 through 2011
Figure 2
Annual and monthly means of HIV-1 RNA and CD4 cell counts.
(A) Annual log10-transformed HIV-1 RNA means and CD4 cell count geometric means calculated from each patient's final values by calendar year. (B) Monthly log10 HIV-1 RNA means and (C) CD4 cell count geometric means calculated from all testing in a given month which represented 21–24% of that year's number of patients (575 persons in 1999 to 854 in 2011). Two-limit Tobit, censored regression models were used to estimate the true mean log10 HIV-1 RNA values by month and year. CD4 cell counts of 0 were assigned the value of 1 cell/µL.