Trends in baseline blood lipid levels in randomized placebo-controlled trials of overweight or obesity from 1990 to 2024.

Background: The global rise in overweight and obesity has reached alarming levels, substantially increasing the risk of metabolic disorders such as dyslipidemia. We outlined the evolving trends in baseline blood lipid levels among patients experiencing overweight or obesity, as observed in placebo-controlled randomized trials, to address the unmet clinical requirements.

Aim: To assess long-term trends in lipid profiles in overweight or obese populations and their association with clinical and treatment factors.

Methods: EMBASE, PubMed, Cochrane Library, and Web of Science databases were searched up to October 9, 2024. Randomized placebo-controlled trials of participants with overweight or obesity, with reports of baseline lipid levels, were included. The main outcome was a correlation between pooled baseline levels of triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) with study year. Subgroup analysis was conducted based on characteristics of the populations and intervention types.

Results: A comprehensive meta-analysis encompassing 866 studies across nearly 60 countries and regions worldwide, involving 3300 participants, revealed significant temporal trends in baseline lipid profiles. The analysis revealed a significant decline in TG (Rs = -0.704, P < 0.001, I ² = 98.6%), TC (Rs = -0.884, P < 0.001, I ² = 99.6%), and LDL-C (Rs = -0.808, P < 0.001, I ² = 96.8%) levels. In contrast, HDL-C (Rs = 0.336, P = 0.041, I ² = 99.2%) levels exhibited a progressive increase over the study period. Subgroup analyses revealed that sex, body mass index, blood pressure, diabetes status, and type of intervention influenced the observed trends, especially with patients receiving pharmacological therapies demonstrating more pronounced improvements (TG: Rs = -0.449, P _adj = 0.011; I ² = 98.9%; TC: Rs = -0.650, P _adj = 0.001; I ² = 99.4%; HDL-C: Rs = 0.650, P _adj = 0.002; I ² = 98.6%; LDL-C: Rs = -0.417, P _adj = 0.031; I² = 98.0%).

Conclusion: Despite rising obesity rates, lipid control has improved over three decades among individuals with overweight or obesity, reflecting the positive impact of public health efforts and effective dyslipidemia treatment strategies.