European Journal of Cardiovascular Medicine

Non-fasting lipid testing has been introduced into several guidelines over the past decade or so  however, the uptake into clincal practice has not been universal. In addition non-fasting lipid panels can provide clinicians with incremental knowledge in assessing  cardiovascular  risk (CVD) patients , particularly for triglycerides. Recently triglyceride levels have emerged as a predictor and therapeutic target for the reduction of cardiovascular diseases 1 . In 2018, the American College of Cardiology/American Heart Association (ACC/AHA )  cholesterol guidelines modified previous 2013 recommendations for fasting and allowed  nonfasting for routine screening,   re-iterated again in the  2019 ACC/AHA prevention guidelines 2.

In 2020 American Diabetes Association guidelines, non-fasting or fasting elevation in triglycerides > 175 mg/dl serves as an indication for physicians to address lifestyle factors and also search for secondary causes 3 . Two major concerns regarding the non- fasting lipid profiles are the similarity between fasting and non-fasting profiles and the predictive value of non-fasting relative to fasting profiles. The findings of  the study Tada et al suggest that non-fasting triglycerides over fasting triglycerides (TG)  is more useful for  risk discrimination for MACE ( major adverse cardiac events) 4 .Most of the Mendelian randomization and association studies focusing on the association  between TG and Atherosclerotic Cardivascular Disease (ASCVD) outcomes, TG levels were mainly measured in non-fasting state 5.

High fasting triglycerides are generally the result of increased Very low density lipoproteins (VLDL) -triglyceride secretion and impaired triglyceride clearance by Lipoprotein Lipase (LPL). the most accepted mechanism for increasing fasting triglycerides is adipose tissue insulin resistance, leading to uninhibited lipolysis, increased free fatty acid flux to the liver and ultimately increased VLDL-triglyceride secretion 6 .

Mechanisms leading to high non-fasting triglycerides are, the mechanisms that also increase fasting triglycerides and failure of insulin to suppress postprandial VLDL secretion, competition between VLDL-triglycerides and chylomicron-triglycerides for LPL hydrolysis, and oversecretion of intestinal chylomicrons are unique drivers of high non-fasting triglycerides. Much attention has been paid to Triglyceride rich lipoproteins (TRLs)  remnants  as a major pathophysiological mechanism linking postprandial lipaemia to increased CVD risk. Increasing dietary triglyceride will increase the number of chylomicron remnants with pro-atherogenic potential and will delay hydrolysis of existing VLDL/VLDL remnants by LPL ,will have even longer residence time, increasing their likelihood of entering the subendothelial space 7 . While much attention has been paid to reducing triglycerides as a strategy for reducing residual risk of CVD after lowering low density lipoproteins (LDL-C,) there is growing support  for post-meal triglycerides measurements in particular, as a tool for screening cardiometabolic risk.

Need of the study-

We spend the majority of our lives in a non-fasting state thus non-fasting lipid screening is more reflective of our physiological state. Non-fasting lipids have been accepted as suitable alternatives to fasting lipid panels for routine screening by numerous guidelines over the past decade. Non-fasting lipids and lipoproteins have similar or even stronger risk associations for CVD risk prediction. The potential for  fasting induced hypoglycemia has been highlighted as an under-appreciated concern with as many as 1 in 4 patients with diabetes reporting a fasting-evoked en-route hypoglycemic event (FEEHD) due to fasting for routine blood test. These add unnecessarily to patient morbidity that could easily be avoided by adopting non-fasting screening⁸.Non-fasting studies are safer for patients with diabetes, elderly, children, and may improve healthcare systems’ efficiency, costs and stakeholder satisfaction.

 
Aim  –

1. The aim of the study  to determine  the variation in  Fasting   and  Non-fasting serum triglycerides  in the same individual with Type 2 Diabetes mellitus.

Objectives-

1. To estimate fasting serum triglycerides and Non-fasting serum triglycerides in

Type 2 Diabetes mellitus patients.

2. To determine the variation in the levels of Fasting serum triglycerides  and Non-fasting triglycerides in Type 2 Diabetes mellitus patients.

This is a  Cross-sectional, hospital based comparitive study  carried out  among   93 diagnosed patients of Type 2 Diabetes mellitus  (according to American Diabetes Association guidelines )  attending  out-patient  Medicine department in Sri Venkateswara RR Govt.Hospital, Tirupati.    Both   male and  female of  age  group    between   35- 65 years,   with  duration of  Type 2 Diabetes mellitus for  >5 yrs are enrolled in the study after  obtaining the Institutional scientific committee and  Institutional Ethics committee approval.

Inclusion criteria- Both male and female of age group between   35- 65 years,  who are with Type2 Diabetes mellitus  for   > 5 years, on treatment  and those who are willing to give written  consent to participate in the study.

Exclusion criteria-  Individuals with co-morbid conditions like-  

• Hypertension Familial hypercholesterolemia,
• Obesity (BMI- >30)
• Thyroid and other hormonal disorders,
• Cardiac or renal disorders,
• on usage of hypolipidemic drugs,
• Post-menopause
• Gestational Diabetes mellitus

Study tools- Clinical proforma, Lab reports

Study variables- Independent- Age, Gender

                           Dependent – fasting triglycerides, Non-fasting triglycerides.

The  sample size  for the present study is calculated  by

                                         n =  [Z_1-α ]² σ²   =   93

                                                    d²

 Sample size is calculated based on comparing mean of population with o reference value. A total of  93 subjects needed to detect 4.17 unit difference between the anticipated and hypothesized mean of the outcome of interest with standard deviation 9.51 and 1% (two sided level )of significance and power 95%⁽⁹⁾ .

Data collection-

A written informed consent was taken from the individuals who are enrolled in the study and relevant history (age,treatment & onset of diabetes mellitus,family history of hypercholesterolemia, any deaths due to CVD , dietary habits etc.) will be taken in pre-designed proforma.

Sample collection- 

 3 ml of  venous fasting blood sample is  collected  by tourniquet method under aseptic conditions, subjected to centrifugation at 3000 rpm for 10-15 mins, serum which gets  separated will be used for the analysis of Serum Triglycerides by   Glycerol-3 phosphate oxidase peroxidase method   and Blood glucose levels by Glucose oxidase peroxidase method  in a fully automated  biochemistry analyser (XL- 640).  Second sample will be collected  2 hrs  after intake of food  which is considered as   non-fasting    ( post prandial sample) sample.  3 ml of post prandial sample is  processed  similarly  as  first sample. 

Expected outcome of the study-     Since people spend most of the day in non-fasting state, Non- fasting triglycerides may better reflect real world metabolic changes and atherogenic risk. The study may suggest non-fasting measurements are practical and equally or more informative than fasting tests.

Ethical consideration-

Before collecting data all subjects are briefed about the purpose of the study and written informed consent will be obtained. Subjects are given the right to withdraw consent at any stage .All investigations done during study will be done free of cost and no financial burden will be imposed on the patient.

Data analysis-

All the data will tabulated and subjected for  Statistical  analysis  using  SPSS software. Quantitative data will be expressed as mean ± SD (Standard deviation). Comparision of fasting and non-fasting  serum  triglycerides and blood glucose was  analyzed by paired sample t-test.  A p value less than 0.05 was assumed to be significant.

In this study   the 93 Type 2 Diabetes  patients were enrolled with age <40 years are 38 and >40 years are 55.   52   were males   and 41 were females.The average duration of Diabetes among  93 patients was >5-10 years are 47, and >10 years  was 46.

The fasting and non- fasting triglycerides in Type 2 diabetics are depicted in Table -1 It was observed that  there is no significant difference  between the fasting  triglycerides and non-fasting triglycerides in Type2 diabetics (p<0.6). An increase of only  6mg/dl was observed in triglycerides   in non-fasting state compared with fasting state.

Thirty six (36) diabetic subjects had hypertriglyceridemia in the fasting state while in post prandial phase 48 diabetic subjects  had hypertriglyceridemia. There was   significant elevation in the number of cases having hypertriglyceridemia in the post-prandial state.                                                                                              

Table-1 Comparision of the parameters, Fasting and Non-fasting.

Table-2 Baseline characteristics of Type2 diabetes mellitus.

Our study suggests little difference between fasting and non-fasting triglycerides of Type 2 Diabetes mellitus patients . The differences in fasting and non- fasting triglycerides was statistically not significant. Several previous studies like Kamrul-Hasan et.al study reported a range of differences 9-64 mg/dl for triglycerides.(9). Other studies including Copenhagen general population study ,the womens Health study in the USA, National Health and Nutrition Examination Survey in the USA, etc explored the possibility of establishing the non-fasting lipid profiles as an alternative to fasting lipid profile.(9).. Moreover our study suggests that the difference between the fasting and non-fasting  triglycerides did not differ significantly in different age groups and sex groups of patients.The fasting triglyceride median levels are 145mg/dl, and non-fasting  triglyceride median  levels are 155mg/dl. As  we observed the absolute difference  in the both triglyceride levels median was 26 and difference was  18%.

In Type 2 Dm as a consequence of insulin resistance, the free fattyacid flux from the adipocytes is increased. This leads to an increased supply of FFA to liver and increased TG synthesis in hepatocytes. Together with defective hepatic clearance of lipoproteins , this plays a key role in the causation dyslipidemia seen in type 2 DM. Diabetic dyslipidemia is an established trigger for atherogenesis and macrovascular disease. (2).

Moreover a non-fasting  lipid profile can also predict the risk of cardiovascular mobidities ,and a suitable alternative for diabetic patients. The Danish society  for clinical biochemistry recommended this non-fasting lipid profile testing as routine practice for their national laboratories in 2009.(3). Despit these recommendations non- fasting lipid profile measurements still need to be universally applicable but additional fasting lipid testing is suggested in certain clinical conditions.

The present study findings support the potentiality of non-fasting lipid measurement as an alternative to fasting measurement as We spend the majority of our lives in a non-fasting state thus non-fasting lipid screening is more reflective of our physiological state. Non-fasting lipids have been accepted as suitable alternatives to fasting lipid panels for routine screening by numerous guidelines over the past decade. Non-fasting lipids and lipoproteins have similar or even stronger risk associations for CVD risk prediction. The potential for  fasting induced hypoglycemia has been highlighted as an under-appreciated concern with as many as 1 in 4 patients with diabetes reporting a fasting-evoked en-route hypoglycemic event (FEEHD) due to fasting for routine blood test. These add unnecessarily to patient morbidity that could easily be avoided by adopting non-fasting screening 8. 

Limitations of the study-

The present study has limitations that we only measured Triglycerides  as only triglycerides are much affected by  non- fasting state in type2 DM. Other parameters like total cholesterol, HDL, LDL are not measured. VLDL is calculated from TGs we can know the alterations in that.

Limited sample size. Single centered study

Lipid measurements done at a specific single time  analysis, it would be better to consider multiple samples with different timings from a same individual to record the variations in non-fasting triglyceride state.

The current study   suggests a small difference is present between the fasting and non-fasting lipid profiles irrespective of age ,sex hence non-fasting lipid measurement is potential alternative in type2DM patients  even to know the cardiovascular risk and to decrease the  chances of hypoglycemic events  ,to decrease multiple visits for the patients.

Table 3 Comparision of Fasting and Non fasting  triglycerides in Type 2 Diabetics

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