title: Low-density lipoprotein cholesterol levels in adults with type 2 diabetes: an alternative equation for accurate estimation and improved cardiovascular risk classification.
abstract: Low-density lipoprotein cholesterol (LDL-C) is a major risk factor for atherosclerotic disease. Despite its limitations, Friedewald-calculated LDL-C (F-LDL-C) remains widely used for LDL-C determination. In this observational study of 1999 adults with type 2 diabetes mellitus (T2DM), we compare the accuracy of F-LDL-C to directly measured LDL-C (M-LDL-C) and derived and validated a new [SMART2D (Singapore Study of MAcro-angiopathy and Micro-Vascular Reactivity in Type 2 Diabetes)] formula to estimate LDL-C. From 1000 randomly selected patients, M-LDL-C was compared to F-LDL-C. Using multiple linear regression to identify independent predictors for M-LDL-C, the SMART2D equation was derived and subsequently validated in the next 981 patients. F-LDL-C was 0.367 (0.216) mmol/L lower than M-LDL-C. This difference was -0.009 (0.189) for SMART2D-LDL-C. Using F-LDL-C, 27% with M-LDL-C ≥2.6 mmol/L were classified as LDL-C <2.6 mmol/L, reduced to 2.1% when using SMART2D-LDL-C. With F-LDL-C, misclassification was greater when triglycerides were ≥2.2 mmol/L, especially for the lower LDL-C cut-offs (1.8 and 2.6 mmol/L), and this was markedly improved with SMART2D-LDL-C. In conclusion, in T2DM, F-LDL-C underestimates M-LDL-C, with misclassifications that may potentially have an impact on therapeutic decisions in T2DM. The SMART2D equation improves accuracy of estimate, reducing misclassifications. Trials will be needed to ascertain the clinical significance of these findings.
authors.affiliation: Diabetes Centre, Khoo Teck Puat Hospital, Singapore Division of Endocrinology, Medicine Unit 2, Department of Medicine, Khoo Teck Puat Hospital, Singapore.
authors.forename: Ester Yeoh
authors.initials: EY
authors.lastname: Chai Kheng
authors.affiliation: Diabetes Centre, Khoo Teck Puat Hospital, Singapore Division of Endocrinology, Medicine Unit 2, Department of Medicine, Khoo Teck Puat Hospital, Singapore.
authors.forename: Sum
authors.initials: S
authors.lastname: Chee Fang
authors.affiliation: Clinical Research Unit, Khoo Teck Puat Hospital, Singapore.
authors.forename: Su
authors.initials: S
authors.lastname: Chang
authors.affiliation: Clinical Services, Khoo Teck Puat Hospital, Singapore.
authors.forename: Serena Low
authors.initials: SL
authors.lastname: Kiat Mun
authors.affiliation: Diabetes Centre, Khoo Teck Puat Hospital, Singapore Division of Endocrinology, Medicine Unit 2, Department of Medicine, Khoo Teck Puat Hospital, Singapore Clinical Research Unit, Khoo Teck Puat Hospital, Singapore.
authors.forename: Lim
authors.initials: L
authors.lastname: Su Chi
authors.affiliation: Division of Nephrology, Medicine Unit 2, Department of Medicine, Khoo Teck Puat Hospital, Singapore.
authors.forename: Yeoh
authors.initials: Y
authors.lastname: Lee Ying
authors.affiliation: Clinical Research Unit, Khoo Teck Puat Hospital, Singapore.
authors.forename: Ng
authors.initials: N
authors.lastname: Xiao Wei
authors.affiliation: Clinical Research Unit, National Healthcare Group Polyclinics, Singapore.
authors.forename: Tang
authors.initials: T
authors.lastname: Wern Ee
authors.affiliation: Yishun Polyclinic, National Healthcare Group Polyclinics, Singapore.
authors.forename: Simon Lee
authors.initials: SL
authors.lastname: Biing Ming
authors.affiliation: Diabetes Centre, Khoo Teck Puat Hospital, Singapore Division of Endocrinology, Medicine Unit 2, Department of Medicine, Khoo Teck Puat Hospital, Singapore Clinical Research Unit, Khoo Teck Puat Hospital, Singapore subramaniam.tavintharan@alexandrahealth.com.sg.
authors.forename: S
authors.initials: S
authors.lastname: Tavintharan
mesh_terms: D000368:Aged; D000465:Algorithms; D002318:Cardiovascular Diseases; D008078:Cholesterol, LDL / Q000097:blood*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment; D012846:Singapore
chemical_list: D008078:Cholesterol, LDL
keywords: Friedewald equation; Low-density lipoprotein cholesterol; estimation; type 2 diabetes