Comparison of Fasting and Non-Fasting Lipid Profiles in Patients with Type 2 Diabetes Mellitus and Healthy Individuals: A Case- Control Study from Aden, Yemen

Technical Summary: Comparison of Fasting and Non-Fasting Lipid Profiles in Patients with Type 2 Diabetes Mellitus and Healthy Individuals

Problem Statement
Dyslipidemia is a critical metabolic complication of Type 2 Diabetes Mellitus (T2DM) and a primary driver of atherosclerotic cardiovascular disease (ASCVD). While international guidelines increasingly suggest that non-fasting lipid testing is a practical alternative for routine screening—particularly for Total Cholesterol (TC) and Low-Density Lipoprotein Cholesterol (LDL-C)—there is a lack of localized evidence from Middle Eastern populations, specifically Yemen. Dietary patterns, healthcare access, and metabolic characteristics vary significantly across regions, creating uncertainty regarding the interpretation of non-fasting lipid results in Yemeni T2DM patients. This study addresses the gap in local data by comparing fasting and non-fasting lipid profiles in T2DM patients versus healthy controls in Aden, Yemen.

Methodology
The research employed an analytical case-control design involving 120 participants recruited from Algamhouria Teaching Hospital in Aden between August and December 2025. The cohort consisted of:

• Cases: 60 clinically diagnosed T2DM patients (duration ≥1 year).
• Controls: 60 age- and sex-matched healthy individuals without a history of diabetes, dyslipidemia, or cardiovascular disease.

Exclusion Criteria: Participants with liver, renal, or thyroid diseases, pregnant women, and those on lipid-lowering therapy were excluded.

Data Collection & Analysis:

• Sampling: Blood samples were collected in two states:
  • Fasting: After an overnight fast of 10–12 hours.
  • Non-fasting: 2–4 hours postprandial (after a regular meal).
• Measurements: Serum Fasting Blood Glucose (FBG), Total Cholesterol (TC), Triglycerides (TG), and High-Density Lipoprotein Cholesterol (HDL-C) were measured using a Cobas c311 automated chemistry analyzer. LDL-C was calculated via the Friedewald formula.
• Statistics: Data were analyzed using SPSS v28. Continuous variables were compared using independent t-tests (between groups) and paired t-tests (within groups). Correlation and association with diabetes duration were assessed using Spearman's coefficient and ANOVA, respectively.

Key Results

1. Demographics and Glucose: The median age for both groups was 52 years. As expected, fasting glucose levels were significantly higher in T2DM patients (154.14 ± 48.03 mg/dL) compared to controls (86.81 ± 11.6 mg/dL; P < 0.001).
2. Fasting Lipid Comparison (T2DM vs. Controls):
   • TC: Significantly higher in T2DM patients (179.7 ± 39.2 mg/dL) than controls (172.5 ± 28.9 mg/dL; P = 0.016).
   • TG, LDL-C, HDL-C: No statistically significant differences were observed between groups in the fasting state, though HDL-C showed borderline significance (P = 0.050).
3. Non-Fasting vs. Fasting (Within T2DM Group):
   • TG: Significantly elevated in the non-fasting state (150.9 ± 74.8 mg/dL) compared to fasting (132.4 ± 64.7 mg/dL; P < 0.001).
   • TC, LDL-C, HDL-C: Levels were significantly lower in the non-fasting state compared to fasting (P < 0.001 for all).
4. Non-Fasting vs. Fasting (Within Control Group):
   • TG: Significantly elevated in the non-fasting state compared to fasting (P < 0.001).
   • TC and HDL-C: Levels were significantly lower in the non-fasting state compared to fasting (P < 0.001).
   • LDL-C: Unlike the other parameters, LDL-C levels showed a slight but statistically significant increase in the non-fasting state compared to fasting (P < 0.001).
5. Non-Fasting Lipid Comparison (T2DM vs. Controls):
   • TG: Showed marginal statistical significance (P = 0.024) with a mean of 150.9 mg/dL (T2DM) vs. 149.4 mg/dL (Controls). The authors note this absolute difference is clinically minimal.
   • TC, LDL-C, HDL-C: No significant differences were found between groups in the non-fasting state.
6. Diabetes Duration: No statistically significant association was found between the duration of diabetes and fasting lipid profile parameters (P > 0.05).

Key Contributions and Significance
This study represents the first comparative analysis of fasting and non-fasting lipid profiles among T2DM patients and healthy controls in Yemen. Its primary contributions include:

• Local Evidence Generation: It provides the first dataset from Yemen to validate or challenge international consensus regarding non-fasting lipid testing in a resource-limited setting with specific dietary and metabolic contexts.
• Clinical Utility of Non-Fasting Testing: The findings support the use of non-fasting samples for routine measurement of TC and LDL-C, as these parameters showed no clinically significant divergence between T2DM patients and healthy controls in the non-fasting state.
• Triglyceride Specificity: The study reinforces that fasting remains essential for accurate triglyceride assessment. It highlights that while non-fasting TG levels are significantly elevated within the diabetic group due to postprandial lipemia, the difference between diabetic and non-diabetic individuals in the non-fasting state is statistically marginal and of limited clinical relevance.
• Statistical vs. Clinical Significance: The paper emphasizes the critical distinction between statistical significance and clinical relevance, noting that small absolute differences in lipid values may yield significant P-values without altering clinical decision-making.

Limitations
The authors acknowledge several constraints: the sample size was modest; the composition of the meal preceding non-fasting sampling was not standardized, potentially introducing variability; glycated hemoglobin (HbA1c) and advanced lipid markers (ApoB, Lp(a)) were not measured; and the single-center nature of the study in Aden may limit generalizability to other regions of Yemen.

Conclusion
The study concludes that T2DM patients in Aden exhibit clinically relevant diabetic dyslipidemia, characterized notably by postprandial triglyceride elevation. While fasting sampling is preferred for precise triglyceride evaluation, non-fasting testing is presented as a practical and feasible alternative for assessing TC and LDL-C, potentially improving patient compliance and cardiovascular risk assessment in diabetic care without compromising clinical utility.