Treatment-mediated Changes Research Articles

Statins, High-Density Lipoprotein Cholesterol, and Regression of Coronary Atherosclerosis

Statins reduce low-density lipoprotein cholesterol (LDL-C) levels and slow progression of coronary atherosclerosis. However, no data exist describing the relationship between statin-induced changes in high-density lipoprotein cholesterol (HDL-C) and disease progression. To investigate the relationship between changes in LDL-C and HDL-C levels and atheroma burden. Post-hoc analysis combining raw data from 4 prospective randomized trials (performed in the United States, North America, Europe, and Australia between 1999 and 2005), in which 1455 patients with angiographic coronary disease underwent serial intravascular ultrasonography while receiving statin treatment for 18 months or for 24 months. Ultrasound analysis was performed in the same core laboratory for all of the studies. Relationship between changes in lipoprotein levels and coronary artery atheroma volume. During statin therapy, mean (SD) LDL-C levels were reduced from 124.0 (38.3) mg/dL (3.2 [0.99] mmol/L) to 87.5 (28.8) mg/dL (2.3 [0.75] mmol/L) (a 23.5% decrease; P<.001), and HDL-C levels increased from 42.5 (11.0) mg/dL (1.1 [0.28] mmol/L) to 45.1 (11.4) mg/dL (1.2 [0.29] mmol/L) (a 7.5% increase; P<.001). The ratio of LDL-C to HDL-C was reduced from a mean (SD) of 3.0 (1.1) to 2.1 (0.9) (a 26.7% decrease; P<.001). These changes were accompanied by a mean (SD) increase in percent atheroma volume from 39.7% (9.8%) to 40.1% (9.7%) (a 0.5% [3.9%] increase; P = .001) and a mean (SD) decrease in total atheroma volume of 2.4 (23.6) mm3 (P<.001). In univariate analysis, mean levels and treatment-mediated changes in LDL-C, total cholesterol, non-HDL cholesterol, apolipoprotein B, and ratio of apolipoprotein B to apolipoprotein A-I were significantly correlated with the rate of atherosclerotic progression, whereas treatment-mediated changes in HDL-C were inversely correlated with atheroma progression. In multivariate analysis, mean levels of LDL-C (beta coefficient, 0.11 [95% confidence interval, 0.07-0.15]) and increases in HDL-C (beta coefficient, -0.26 [95% confidence interval, -0.41 to -0.10]) remained independent predictors of atheroma regression. Substantial atheroma regression (> or =5% reduction in atheroma volume) was observed in patients with levels of LDL-C less than the mean (87.5 mg/dL) during treatment and percentage increases of HDL-C greater than the mean (7.5%; P<.001). No significant differences were found with regard to clinical events. Statin therapy is associated with regression of coronary atherosclerosis when LDL-C is substantially reduced and HDL-C is increased by more than 7.5%. These findings suggest that statin benefits are derived from both reductions in atherogenic lipoprotein levels and increases in HDL-C, although it remains to be determined whether the atherosclerotic regression associated with these changes in lipid levels will translate to meaningful reductions in clinical events and improved clinical outcomes.

Treatment-mediated changes in human immunodeficiency virus (HIV) type 1 RNA and CD4 cell counts as predictors of weight growth failure, cognitive decline, and survival in HIV-infected children.

This meta-analysis of 5 large studies of the Pediatric AIDS Clinical Trials Group was undertaken to evaluate the predictive value of antiretroviral treatment-mediated changes in 3 markers of human immunodeficiency virus (HIV) type 1 disease progression-HIV-1 RNA level, CD4 cell count, and CD4 percentage-for weight growth failure, cognitive decline, and survival in HIV-infected children. Proportional hazards models were used to assess the prognostic value of the markers at baseline and after 24 weeks of treatment, with data from 1089 children. Among children receiving nucleoside with or without nonnucleoside reverse-transcriptase inhibitors, higher immunologic and lower virologic markers at baseline and after 24 weeks were significant independent predictors of survival, whereas virologic markers were significant predictors of weight growth and cognitive failure in children >1 year old. The finding of differential age effects on pediatric-specific clinical outcomes emphasizes the need for continued investigation of treatment effects in children.

Human immunodeficiency virus type 1 RNA level and CD4 count as prognostic markers and surrogate end points: a meta-analysis. HIV Surrogate Marker Collaborative Group.

To evaluate treatment-mediated changes in HIV-1 RNA and CD4 count as prognostic markers and surrogate end points for disease progression (AIDS/death). Data from 13,045 subjects in all 16 randomized trials comparing nucleoside analogue reverse transcriptase inhibitors and having HIV-1 RNA measurements at 24 weeks were obtained. A total of 3146 subjects had HIV-1 RNA and CD4 count determinations at 24 weeks after starting treatment. At Week 24, the percentage of subjects experiencing an HIV-1 RNA decrease of >1 log10 copies/ml or a CD4 count increase of >33% was similar (22% vs. 25%). Changes in both markers at Week 24 were significant independent predictors of AIDS/death: across trials, the average reduction in hazard was 51% per 1 log10 HIV-1 RNA copies/ml decrease (95% confidence interval: 41%, 59%) and 20% per 33% CD4 count increase (17%, 24%). In univariate analyses, the hazard ratio for AIDS/death in randomized treatment comparisons was significantly associated with differences between treatments in mean area under the curve of HIV-1 RNA changes to Weeks 8 and 24 (AUCMB) and mean CD4 change at Week 24, but, in multivariate analysis, only mean CD4 change was significant. Change in HIV-1 RNA, particularly using AUCMB, and in CD4 count should be measured to aid patient management and evaluation of treatment activity in clinical trials. However, short-term changes in these markers are imperfect as surrogate end points for long-term clinical outcome because two randomized treatment comparisons may show similar differences between treatments in marker changes but not similar differences in progression to AIDS/death.