P2.192: Examining Biomarkers for Dyslipidemia, Diabetes, and NAFLD by CDC’s Extended BMI Percentiles in US Youth Aged 6-17 Years

Background: Excess adiposity promotes chronic inflammation and can contribute to cardiometabolic health risks. In 2022, CDC released Extended BMI-for-Age Growth Charts to support growth monitoring for youths with very high BMIs. It is well-established that youths with obesity have cardiometabolic risk factors; however, research to date has not assessed how extended BMI percentiles (BMIp) relate to increased risk. Using IQVIA’s Ambulatory Electronic Medical Records, we examined associations between extended BMIp and cardiometabolic biomarkers in US youths with overweight or obesity.

Methods: Heights and weights were cleaned using growthcleanr (R package). BMIs were categorized based on extended BMIp: ≥85th to < 95th (overweight) and 4 obesity sub-categories including 95th to < 98th (moderate or class 1 obesity), 98- < 99th, 99- < 99.9th, and ≥99.9th percentile. We constructed six analytic samples, each comprising patients 6-17y with BMI≥85th percentile and a laboratory test for ≥1 of these biomarkers in 2022: total cholesterol (TC), low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), triglycerides, glycated hemoglobin (HbA1c), alanine transaminase (ALT). Abnormal values were defined as TC≥200 mg/dL; LDL≥130 mg/dL; HDL < 40 mg/dL; TG≥100 mg/dL (6-9y) or ≥130 mg/dL (10-17y); HbA1c≥5.7%; and ALT≥25 U/L (males) or ≥22 U/L (females). We calculated crude prevalence and adjusted prevalence ratios (aPR) for abnormal lab values by extended BMIp, controlling for sex and age.

Results: One third of patients had each of the following: elevated triglycerides, elevated ALT, and low HDL. Prevalence of low HDL ranged from 19% in those with BMIp 85- < 95 to 45% in BMIp≥99.9. Nine percent had elevated LDL or TC with less variation across BMIp. Twenty percent had elevated HbA1c (≥5.7%), ranging from 12% in those with BMIp 85- < 95 to 32% in BMIp≥99.9. More than 90% of those with elevated HbA1c had values in the prediabetes range (5.7- < 6.5%). Higher extended BMIp generally corresponded to higher probability of abnormal biomarkers. For example, compared to patients with overweight, those with obesity were 1.5-2.8x as likely to have elevated HbA1c, with likelihood increasing as BMIp increased. Similarly, patients with obesity were more likely to have elevated triglycerides (aPR range: 1.5-1.9), elevated ALT (aPR range: 1.6-2.6), and low HDL (aPR range: 1.5-2.4) than those with overweight. A dose response pattern was observed up to the 99th for ALT and triglycerides and 99.9th percentile for HDL.

Conclusion: Risk for abnormal cardiometabolic biomarkers was not homogeneous across the extended BMIp spectrum. Having BMI at the extended 98th or 99th percentile was associated with higher likelihood for multiple biomarkers, including HbA1c, ALT, triglycerides, and HDL, beyond those with overweight and often those with moderate obesity. Information on associations between extended BMIp and health outcomes could facilitate clinical practice for pediatric obesity, including identifying those at highest risk and informing when to escalate evaluation or treatment.