Journal of Clinical and Diagnostic Research, ISSN - 0973 - 709X

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Dr Mohan Z Mani

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Believers Church Medical College,
Thiruvalla, Kerala
On Sep 2018




Prof. Somashekhar Nimbalkar

"Over the last few years, we have published our research regularly in Journal of Clinical and Diagnostic Research. Having published in more than 20 high impact journals over the last five years including several high impact ones and reviewing articles for even more journals across my fields of interest, we value our published work in JCDR for their high standards in publishing scientific articles. The ease of submission, the rapid reviews in under a month, the high quality of their reviewers and keen attention to the final process of proofs and publication, ensure that there are no mistakes in the final article. We have been asked clarifications on several occasions and have been happy to provide them and it exemplifies the commitment to quality of the team at JCDR."



Prof. Somashekhar Nimbalkar
Head, Department of Pediatrics, Pramukhswami Medical College, Karamsad
Chairman, Research Group, Charutar Arogya Mandal, Karamsad
National Joint Coordinator - Advanced IAP NNF NRP Program
Ex-Member, Governing Body, National Neonatology Forum, New Delhi
Ex-President - National Neonatology Forum Gujarat State Chapter
Department of Pediatrics, Pramukhswami Medical College, Karamsad, Anand, Gujarat.
On Sep 2018




Dr. Kalyani R

"Journal of Clinical and Diagnostic Research is at present a well-known Indian originated scientific journal which started with a humble beginning. I have been associated with this journal since many years. I appreciate the Editor, Dr. Hemant Jain, for his constant effort in bringing up this journal to the present status right from the scratch. The journal is multidisciplinary. It encourages in publishing the scientific articles from postgraduates and also the beginners who start their career. At the same time the journal also caters for the high quality articles from specialty and super-specialty researchers. Hence it provides a platform for the scientist and researchers to publish. The other aspect of it is, the readers get the information regarding the most recent developments in science which can be used for teaching, research, treating patients and to some extent take preventive measures against certain diseases. The journal is contributing immensely to the society at national and international level."



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Professor and Head
Department of Pathology
Sri Devaraj Urs Medical College
Sri Devaraj Urs Academy of Higher Education and Research , Kolar, Karnataka
On Sep 2018




Dr. Saumya Navit

"As a peer-reviewed journal, the Journal of Clinical and Diagnostic Research provides an opportunity to researchers, scientists and budding professionals to explore the developments in the field of medicine and dentistry and their varied specialities, thus extending our view on biological diversities of living species in relation to medicine.
Knowledge is treasure of a wise man. The free access of this journal provides an immense scope of learning for the both the old and the young in field of medicine and dentistry as well. The multidisciplinary nature of the journal makes it a better platform to absorb all that is being researched and developed. The publication process is systematic and professional. Online submission, publication and peer reviewing makes it a user-friendly journal.
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Dr Saumya Navit
Professor and Head
Department of Pediatric Dentistry
Saraswati Dental College
Lucknow
On Sep 2018




Dr. Arunava Biswas

"My sincere attachment with JCDR as an author as well as reviewer is a learning experience . Their systematic approach in publication of article in various categories is really praiseworthy.
Their prompt and timely response to review's query and the manner in which they have set the reviewing process helps in extracting the best possible scientific writings for publication.
It's a honour and pride to be a part of the JCDR team. My very best wishes to JCDR and hope it will sparkle up above the sky as a high indexed journal in near future."



Dr. Arunava Biswas
MD, DM (Clinical Pharmacology)
Assistant Professor
Department of Pharmacology
Calcutta National Medical College & Hospital , Kolkata




Dr. C.S. Ramesh Babu
" Journal of Clinical and Diagnostic Research (JCDR) is a multi-specialty medical and dental journal publishing high quality research articles in almost all branches of medicine. The quality of printing of figures and tables is excellent and comparable to any International journal. An added advantage is nominal publication charges and monthly issue of the journal and more chances of an article being accepted for publication. Moreover being a multi-specialty journal an article concerning a particular specialty has a wider reach of readers of other related specialties also. As an author and reviewer for several years I find this Journal most suitable and highly recommend this Journal."
Best regards,
C.S. Ramesh Babu,
Associate Professor of Anatomy,
Muzaffarnagar Medical College,
Muzaffarnagar.
On Aug 2018




Dr. Arundhathi. S
"Journal of Clinical and Diagnostic Research (JCDR) is a reputed peer reviewed journal and is constantly involved in publishing high quality research articles related to medicine. Its been a great pleasure to be associated with this esteemed journal as a reviewer and as an author for a couple of years. The editorial board consists of many dedicated and reputed experts as its members and they are doing an appreciable work in guiding budding researchers. JCDR is doing a commendable job in scientific research by promoting excellent quality research & review articles and case reports & series. The reviewers provide appropriate suggestions that improve the quality of articles. I strongly recommend my fraternity to encourage JCDR by contributing their valuable research work in this widely accepted, user friendly journal. I hope my collaboration with JCDR will continue for a long time".



Dr. Arundhathi. S
MBBS, MD (Pathology),
Sanjay Gandhi institute of trauma and orthopedics,
Bengaluru.
On Aug 2018




Dr. Mamta Gupta,
"It gives me great pleasure to be associated with JCDR, since last 2-3 years. Since then I have authored, co-authored and reviewed about 25 articles in JCDR. I thank JCDR for giving me an opportunity to improve my own skills as an author and a reviewer.
It 's a multispecialty journal, publishing high quality articles. It gives a platform to the authors to publish their research work which can be available for everyone across the globe to read. The best thing about JCDR is that the full articles of all medical specialties are available as pdf/html for reading free of cost or without institutional subscription, which is not there for other journals. For those who have problem in writing manuscript or do statistical work, JCDR comes for their rescue.
The journal has a monthly publication and the articles are published quite fast. In time compared to other journals. The on-line first publication is also a great advantage and facility to review one's own articles before going to print. The response to any query and permission if required, is quite fast; this is quite commendable. I have a very good experience about seeking quick permission for quoting a photograph (Fig.) from a JCDR article for my chapter authored in an E book. I never thought it would be so easy. No hassles.
Reviewing articles is no less a pain staking process and requires in depth perception, knowledge about the topic for review. It requires time and concentration, yet I enjoy doing it. The JCDR website especially for the reviewers is quite user friendly. My suggestions for improving the journal is, more strict review process, so that only high quality articles are published. I find a a good number of articles in Obst. Gynae, hence, a new journal for this specialty titled JCDR-OG can be started. May be a bimonthly or quarterly publication to begin with. Only selected articles should find a place in it.
An yearly reward for the best article authored can also incentivize the authors. Though the process of finding the best article will be not be very easy. I do not know how reviewing process can be improved. If an article is being reviewed by two reviewers, then opinion of one can be communicated to the other or the final opinion of the editor can be communicated to the reviewer if requested for. This will help ones reviewing skills.
My best wishes to Dr. Hemant Jain and all the editorial staff of JCDR for their untiring efforts to bring out this journal. I strongly recommend medical fraternity to publish their valuable research work in this esteemed journal, JCDR".



Dr. Mamta Gupta
Consultant
(Ex HOD Obs &Gynae, Hindu Rao Hospital and associated NDMC Medical College, Delhi)
Aug 2018




Dr. Rajendra Kumar Ghritlaharey

"I wish to thank Dr. Hemant Jain, Editor-in-Chief Journal of Clinical and Diagnostic Research (JCDR), for asking me to write up few words.
Writing is the representation of language in a textual medium i e; into the words and sentences on paper. Quality medical manuscript writing in particular, demands not only a high-quality research, but also requires accurate and concise communication of findings and conclusions, with adherence to particular journal guidelines. In medical field whether working in teaching, private, or in corporate institution, everyone wants to excel in his / her own field and get recognised by making manuscripts publication.


Authors are the souls of any journal, and deserve much respect. To publish a journal manuscripts are needed from authors. Authors have a great responsibility for producing facts of their work in terms of number and results truthfully and an individual honesty is expected from authors in this regards. Both ways its true "No authors-No manuscripts-No journals" and "No journalsNo manuscriptsNo authors". Reviewing a manuscript is also a very responsible and important task of any peer-reviewed journal and to be taken seriously. It needs knowledge on the subject, sincerity, honesty and determination. Although the process of reviewing a manuscript is a time consuming task butit is expected to give one's best remarks within the time frame of the journal.
Salient features of the JCDR: It is a biomedical, multidisciplinary (including all medical and dental specialities), e-journal, with wide scope and extensive author support. At the same time, a free text of manuscript is available in HTML and PDF format. There is fast growing authorship and readership with JCDR as this can be judged by the number of articles published in it i e; in Feb 2007 of its first issue, it contained 5 articles only, and now in its recent volume published in April 2011, it contained 67 manuscripts. This e-journal is fulfilling the commitments and objectives sincerely, (as stated by Editor-in-chief in his preface to first edition) i e; to encourage physicians through the internet, especially from the developing countries who witness a spectrum of disease and acquire a wealth of knowledge to publish their experiences to benefit the medical community in patients care. I also feel that many of us have work of substance, newer ideas, adequate clinical materials but poor in medical writing and hesitation to submit the work and need help. JCDR provides authors help in this regards.
Timely publication of journal: Publication of manuscripts and bringing out the issue in time is one of the positive aspects of JCDR and is possible with strong support team in terms of peer reviewers, proof reading, language check, computer operators, etc. This is one of the great reasons for authors to submit their work with JCDR. Another best part of JCDR is "Online first Publications" facilities available for the authors. This facility not only provides the prompt publications of the manuscripts but at the same time also early availability of the manuscripts for the readers.
Indexation and online availability: Indexation transforms the journal in some sense from its local ownership to the worldwide professional community and to the public.JCDR is indexed with Embase & EMbiology, Google Scholar, Index Copernicus, Chemical Abstracts Service, Journal seek Database, Indian Science Abstracts, to name few of them. Manuscriptspublished in JCDR are available on major search engines ie; google, yahoo, msn.
In the era of fast growing newer technologies, and in computer and internet friendly environment the manuscripts preparation, submission, review, revision, etc and all can be done and checked with a click from all corer of the world, at any time. Of course there is always a scope for improvement in every field and none is perfect. To progress, one needs to identify the areas of one's weakness and to strengthen them.
It is well said that "happy beginning is half done" and it fits perfectly with JCDR. It has grown considerably and I feel it has already grown up from its infancy to adolescence, achieving the status of standard online e-journal form Indian continent since its inception in Feb 2007. This had been made possible due to the efforts and the hard work put in it. The way the JCDR is improving with every new volume, with good quality original manuscripts, makes it a quality journal for readers. I must thank and congratulate Dr Hemant Jain, Editor-in-Chief JCDR and his team for their sincere efforts, dedication, and determination for making JCDR a fast growing journal.
Every one of us: authors, reviewers, editors, and publisher are responsible for enhancing the stature of the journal. I wish for a great success for JCDR."



Thanking you
With sincere regards
Dr. Rajendra Kumar Ghritlaharey, M.S., M. Ch., FAIS
Associate Professor,
Department of Paediatric Surgery, Gandhi Medical College & Associated
Kamla Nehru & Hamidia Hospitals Bhopal, Madhya Pradesh 462 001 (India)
E-mail: drrajendrak1@rediffmail.com
On May 11,2011




Dr. Shankar P.R.

"On looking back through my Gmail archives after being requested by the journal to write a short editorial about my experiences of publishing with the Journal of Clinical and Diagnostic Research (JCDR), I came across an e-mail from Dr. Hemant Jain, Editor, in March 2007, which introduced the new electronic journal. The main features of the journal which were outlined in the e-mail were extensive author support, cash rewards, the peer review process, and other salient features of the journal.
Over a span of over four years, we (I and my colleagues) have published around 25 articles in the journal. In this editorial, I plan to briefly discuss my experiences of publishing with JCDR and the strengths of the journal and to finally address the areas for improvement.
My experiences of publishing with JCDR: Overall, my experiences of publishing withJCDR have been positive. The best point about the journal is that it responds to queries from the author. This may seem to be simple and not too much to ask for, but unfortunately, many journals in the subcontinent and from many developing countries do not respond or they respond with a long delay to the queries from the authors 1. The reasons could be many, including lack of optimal secretarial and other support. Another problem with many journals is the slowness of the review process. Editorial processing and peer review can take anywhere between a year to two years with some journals. Also, some journals do not keep the contributors informed about the progress of the review process. Due to the long review process, the articles can lose their relevance and topicality. A major benefit with JCDR is the timeliness and promptness of its response. In Dr Jain's e-mail which was sent to me in 2007, before the introduction of the Pre-publishing system, he had stated that he had received my submission and that he would get back to me within seven days and he did!
Most of the manuscripts are published within 3 to 4 months of their submission if they are found to be suitable after the review process. JCDR is published bimonthly and the accepted articles were usually published in the next issue. Recently, due to the increased volume of the submissions, the review process has become slower and it ?? Section can take from 4 to 6 months for the articles to be reviewed. The journal has an extensive author support system and it has recently introduced a paid expedited review process. The journal also mentions the average time for processing the manuscript under different submission systems - regular submission and expedited review.
Strengths of the journal: The journal has an online first facility in which the accepted manuscripts may be published on the website before being included in a regular issue of the journal. This cuts down the time between their acceptance and the publication. The journal is indexed in many databases, though not in PubMed. The editorial board should now take steps to index the journal in PubMed. The journal has a system of notifying readers through e-mail when a new issue is released. Also, the articles are available in both the HTML and the PDF formats. I especially like the new and colorful page format of the journal. Also, the access statistics of the articles are available. The prepublication and the manuscript tracking system are also helpful for the authors.
Areas for improvement: In certain cases, I felt that the peer review process of the manuscripts was not up to international standards and that it should be strengthened. Also, the number of manuscripts in an issue is high and it may be difficult for readers to go through all of them. The journal can consider tightening of the peer review process and increasing the quality standards for the acceptance of the manuscripts. I faced occasional problems with the online manuscript submission (Pre-publishing) system, which have to be addressed.
Overall, the publishing process with JCDR has been smooth, quick and relatively hassle free and I can recommend other authors to consider the journal as an outlet for their work."



Dr. P. Ravi Shankar
KIST Medical College, P.O. Box 14142, Kathmandu, Nepal.
E-mail: ravi.dr.shankar@gmail.com
On April 2011
Anuradha

Dear team JCDR, I would like to thank you for the very professional and polite service provided by everyone at JCDR. While i have been in the field of writing and editing for sometime, this has been my first attempt in publishing a scientific paper.Thank you for hand-holding me through the process.


Dr. Anuradha
E-mail: anuradha2nittur@gmail.com
On Jan 2020

Important Notice

Original article / research
Year : 2022 | Month : January | Volume : 16 | Issue : 1 | Page : BC06 - BC11 Full Version

Assessing the Validity of Nine Different Formulae for LDL-C Estimation in a Tertiary Care Centre, Hyderabad, India


Published: January 1, 2022 | DOI: https://doi.org/10.7860/JCDR/2022/50590.15903
Bhavya Sirivelu, Manaswini Namilakonda, Krishnaveni Soma, Sasikala Thallapaneni, Dhana Lakshmi Annavarapu, V Sampath Kumar, DS Jagannadha Phaneendra

1. Senior Resident, Department of Biochemistry, Employees State Insurance Corporation Medical College and Hospital, Sanathnagar, Hyderabad, Telangana, India. 2. Assistant Professor, Department of Biochemistry, Employees State Insurance Corporation Medical College and Hospital, Sanathnagar, Hyderabad, Telangana, India. 3. Assistant Professor, Department of Biochemistry, Employees State Insurance Corporation Medical College and Hospital, Sanathnagar, Hyderabad, Telangana, India. 4. Tutor, Department of Biochemistry, Employees State Insurance Corporation Medical College and Hospital, Sanathnagar, Hyderabad, Telangana, India. 5. Senior Specialist, Department of Biochemistry, Employees State Insurance Corporation Medical College and Hospital, Sanathnagar, Hyderabad, Telangana, India. 6. Professor and Head, Department of Biochemistry, Employees State Insurance Corporation Medical College and Hospital, Sanathnagar, Hyderabad, Telangana, India. 7. Associate Professor, Department of Bioch

Correspondence Address :
Manaswini Namilakonda,
Assistant Professor, Department of Biochemistry, Employees State Insurance
Corporation Medical College and Hospital, Sanathnagar, Hyderabad, Telangana, India.
E-mail: drkmanaswini@gmail.com

Abstract

Introduction: Conventionally, Friedewald’s formula has been used to calculate Low Density Lipoprotein- Cholesterol (LDL-C) due to its simplicity and convenience although it has limitations. Many researchers have proposed different formulae to increase the accuracy of calculated LDL-C, but none of those have concluded about a single best formula owing to differences in selected study populations. As LDL-C measurement is of utmost importance for assessing the cardiovascular risk according to National Cholesterol Education Programme’s (NCEP) Adult Treatment Panel III (ATP III), a search for a better formula to improve accuracy of cardiovascular disease (CVD) risk prediction is essential.

Aim: To assess the validity of calculated LDL-C by nine formulae and compare them to values obtained by the direct method.

Materials and Methods: A total of 324 participants were assessed retrospectively for serum lipid profile by standard methods from December 2020 to February 2021 at Employee State Insurance Corporation Medical College and Hospital, Sanathnagar, Hyderabad, Telangana, India. LDL-C was calculated using nine different formulae (Ahmadi, Anand, Chen, de Cordova, Friedewald, Hattori, Martin-Hopkins, Puavillai and Vujovic) and correlated with direct LDL-C. For further analysis, subjects were divided into five groups based on the Triglyceride levels (TG) viz; group 1 (TG <100 mg/dL), group 2 (TG: 100-150 mg/dL), group 3 (TG: 151-200 mg/dL), group 4 (TG: 201-400 mg/dL), group 5 (TG >400 mg/dL). Statistical analysis was done using Statistical Package for Social Sciences (SPSS) version 23.0.

Results: Total of 324 lipid profile reports were analysed and calculated LDL-C by nine formulas were compared. At TG levels <100 mg/dL, Puavillai was the most accurate. Between TG levels 100-200 mg/dL, Martin-Hopkins showed better accuracy and correlation with direct LDL-C. At TG levels 201-400 and >400 mg/dL, Puavillai had better accuracy. But, none of the formulae showed strong correlation with Direct LDL-C at TG >400 mg/dL. ROC curves also showed that Puavillai performed better among all formulae, at all TG levels.

Conclusion: Among the nine equations, Puavillai and Martin-Hopkins showed highest accuracy and better performance than others in the present study population. Martin-Hopkins can be used at TG levels of 100-200 mg/dL while Puavillai can be used at lower and higher TG levels in this demographic population for estimating LDL-C.

Keywords

Cardiovascular, Calculated low, Cardiovascular disease, Low density lipoprotein cholesterol, Triglyceride

Cardiovascular diseases are the leading cause of global mortality (1),(2). Lipoprotein levels have been touted to be markers of cardiovascular risk assessment from a long time (3),(4). Among the lipoprotein subtypes, Low Density Lipoproteins- Cholesterol (LDL-C) carries cholesterol from liver to peripheral tissues and hence has pro-atherogenic properties. So, LDL-C is one of the crucial biochemical parameters which has been used to assess the cardiovascular risk according to the National Cholesterol Education Programme’s (NCEP) Adult Treatment Panel III (ATP III) (5). Therefore, the accuracy of LDL-C measurement plays an important role.

The gold standard for measurement of LDL-C is by ultracentrifugation and beta-quantification which are laborious, time taking and expensive to be used in routine laboratory practice (6). Other methods used are direct estimation by homogenous assays or indirectly by calculating with use of various formulae that incorporate different lipoprotein levels like Triglycerides (TG) and non High Density Lipoprotein (NHDL) cholesterol which are measured by standard methods. In developing countries, where resources are limited, many laboratories cannot afford to perform direct assay of LDL-C as it is expensive. Hence, various clinical laboratories use a less expensive and easy method where LDL-C is calculated by using different formulae. There are several published equations for calculating LDL-C like Ahmadi, Anandraja, Chen, de Cardovo, Friedwald’s, Hattori, Martin-Hopkins, Puavillai and Vujovik equations (7),(8),(9),(10),(11),(12),(13),(14),(15).

The most commonly used formula is Friedewald’s equation which incorporates Total Cholesterol (TC), Triglyceride (TG) and High-Density Lipoprotein (HDL) cholesterol. It assumes that Very Low-Density Lipoprotein Cholesterol (VLDL-C) greatly influences TG levels and that the ratio between TG and VLDL-C is fixed as 5, but the actual ratios may vary. Different studies have shown that Friedwald’s method yields better results in patients with serum TG concentrations less than 400 mg/dL (16),(17). Many researchers have stated that Friedewald’s equation tends to either overestimate or underestimate LDL-C in individuals with conditions such as diabetes mellitus, alcoholic liver disease, and chronic renal failure who are on dialysis (18),(19),(20),(21). Both overestimation and underestimation of LDL-C can pose problems to patients. While overestimation leads to prescription of unnecessary medication; underestimation can delay proper treatment, increasing cardiac risk in them. For this reason, many researchers have attempted to modify the equation by changing the TG: VLDL-C ratio.

But, each equation provides a different result. This variation might be probably due to limitations of the selected study population that was used to derive the equation as they differ in demography, ethnicity and environmental influences. This indicates the need to develop a more local approach to the formula which can be used to calculate LDL-C. Therefore, the present study attempted to compare nine different formulae i.e., Ahmadi, Anand, Chen, de Cardovo, Friedwald, Hattori, Martin-Hopkins, Puavillai and Vujovic equations in order to analyse which formula best suits Indian population.

Material and Methods

This study was a retrospective analytical study comprising of 324 lipid profile reports. The data was collected from the laboratory database from the subjects attending Outpatient Department of Employee State Insurance Corporation (ESIC) Medical College and Hospital, Sanathnagar, Hyderabad, Telangana, India and analysed for a period of three months from December 2020 to February 2021, after obtaining Institutional Ethical Committee clearance (ESICMC/SNR/IEC-F0238/12-2020). The laboratory serves a large tertiary care academic hospital. Patient details were anonymised except for age and gender. All subjects aged above 18 years who came to the biochemistry laboratory for a complete lipid profile investigation were included in the study.

All the 324 laboratory reports of the participants included, were divided into five groups based on their TG levels (Group 1: TG <100 mg/dL, Group 2: TG=100-150 mg/dL, Group 3: TG=151-200 mg/dL, Group 4: TG=201-400 mg/dL, Group 5: TG >400 mg/dL).

Blood samples were collected as per the standard protocol i.e., after an overnight fast of 10-12 hours, 3 mL of venous blood in a plain tube, serum separated and analysed immediately to determine direct LDL-C (Homogeneous Enzymatic Colorimetric Assay), HDL-C (Homogeneous Enzymatic Colorimetric Assay), TG {Glycerine Phosphate Oxidase Peroxidase (GPO-PAP)} and TC (Cholesterol Oxidase Peroxidase (CHOD-POD) Method), on Roche Cobas C311 Chemistry Analysers (Roche Diagnostics GmbH, Mannheim, Germany). Apart from direct homogenous assay, calculated LDL-C was also determined using the following nine formulae:

1. Ahmadi: LDL-C=TC/1.19+TG/1.9–HDL-C/1.1 (7)
2. Anandaraja: LDL-C=(0.9×TC)–(0.9×TG/5)–28 (8)
3. Chen: LDL-C=(TC–HDL-C)×0.9–(TG×0.1) (9)
4. de Cordova: LDL-C=0.7516×(TC–HDL-C) (10)
5. Friedewald: LDL-C=TC–HDL-C–TG/5 (11)
6. Hattori: LDL-C=(0.94×TC)–(0.94×HDL-C)–(0.19×TG) (12)
7. Martin-Hopkins: LDL=TC–HDL–TG/novel factor derived using an LDL-C calculator (13)
8. Puavillai: LDL-C=TC–HDL-C–TG/6 (14)
9. Vujovic: LDL-C=TC–HDL-C–(TG/6.85) (15)

Statistical Analysis

Statistical analysis was performed using Statistical Package for the Social Science (SPSS) version 23.0. Data was expressed as mean and standard deviation. Associations were analysed using Pearson’s correlation test. Paired t-test was also performed to compare the means. Diagnostic Performance of the nine formulae was analysed using Area Under Curve (AUC) obtained by constructing Receiver Operating Characteristic (ROC) Curves. Two-tailed p-value <0.05 was taken as significant.

Conversion factors to SI units: To convert TG from mg/dL to mmol/L multiply by 0.01129. To convert TC, LDL-C and HDL-C from mg/dL to mmol/L multiply by 0.02586 (22).

Results

A total of 324 participants of which 120 (37.04%) were females and 204 (62.96%) were males with a mean age of 45±15 years were included. The demographic distribution and lipid data of the participants are shown (Table/Fig 1). LDL-C estimated by direct homogeneous assay and calculated using nine different formulae were compared and correlated.

Lipoprotein Concentrations

The study population was divided into 5 groups based on their TG levels (Group 1: TG <100 mg/dL, Group 2: TG=100-150 mg/dL, significantGroup 3: TG=151-200 mg/dL, Group 4: TG=201-400 mg/dL, Group 5: TG >400 mg/dL) in order to evaluate the performance of these nine formulae at different levels of TG, especially at higher and lower levels of TG where the commonly used Friedwald formula has limitations of usage.

LDL-C concentrations, their distributions and correlations with direct LDL-C in the 5 groups are shown in (Table/Fig 2),(Table/Fig 3),(Table/Fig 4),(Table/Fig 5),(Table/Fig 6),(Table/Fig 7),(Table/Fig 8),(Table/Fig 9),(Table/Fig 10),(Table/Fig 11),(Table/Fig 12),(Table/Fig 13). The present study showed that at TG levels <100 mg/dL, Puavillai showed the least mean difference and best correlation with direct LDL-C (r=0.821).

At TG levels 100-150 mg/dL and 151-200 mg/dL, Martin-Hopkins LDL-C showed the least mean difference and best correlation with direct LDL-C (r=0.928,0.962). Puavillai LDL-C showed the least mean difference and best correlation (r=0.946) with direct LDL-C followed by Martin-Hopkins (r=0.932) at TG levels 201-400 mg/dL. Also, at higher TG levels i.e., >400 mg/dL, Puavillai LDL-C had the least mean difference of -1.3, all other formulae including Martin-Hopkins were highly inaccurate.

Diagnostic Performance

Receiver Operating Characteristic (ROC) curves were constructed to analyse the performance of calculated LDL-C using the nine different formulae [Table/Fig-14[,(Table/Fig 15). Out of all, Puavillai showed the best performance followed by Martin-Hopkins and then Friedewald’s LDL-C.

Discussion

According to National Cholesterol Education Programme (NCEP) guidelines, LDL-C level is crucial for risk assessment, instituting treatment to prevent cardiovascular diseases and monitoring (23). Despite of inherent limitations of Friedewald formula, it is one of the commonly used method, as the reference method (ultracentrifugation) to measure LDL is laborious, costly and not suitable for resource limited setting. Thus, accurate measurement of LDL-C is important to avoid adverse outcome to patients.

characteristicHowever, many formulas were derived previously to quantify LDL-C precisely than the widely used Friedewald's formula. Furthermore, under estimate and over estimate of LDL-C leads to delay in treatment and unnecessary exposure to drugs respectively. Therefore, determining an equation for estimation of LDL-C in different population with good comparability to direct LDL-C measurement is essential.

In this study, there was a positive correlation between direct LDL-C and calculated LDL-C with all formulae. This is in line with other studies where the LDL-C was measured by different homogenous assays [15,24,16,25-28]. The study population was divided into five groups of different TG levels to validate the nine formulae at these TG levels. Most of these formulae showed high correlation with direct LDL-C at different levels of TG.

In the present study, when compared to nine common formulae, Puavillai was the best equation to estimate LDL-C in Indian population and the next best is Martin- Hopkins equation. At the TG level <100 mg/dL, Puavillai had the highest accuracy followed by Martin-Hopkins in contrary to a similar analysis where de Cordova had the highest accuracy (26). Further, Puavillai equation correlated maximally with direct LDL-C at all levels of TG except at TG 100 mg/dL -200 mg/dL in Indian population. It was also inferred from this study results that Friedewald’s formula overestimated LDL-C in almost all TG groups, the amount of overestimation increased with the increase in TG, this was in consistent with the results previously reported by Mora S et al., Martin SS et al., and Kannan S et al., (26),(29),(30). However, it was next most accurate after Puavillai and Martin-Hopkins. Whereas, Krishnaveni P and Gowda VM demonstrated that Friedewald equation correlated with direct LDL-C at all levels of TG except at TG less than 100 mg/dL in Indian population, however they did not include samples with TG>400 mg/dL (31). According to Wadhwa N and Krishnaswamy R, vijovic formula was the most accurate equation for estimation of LDL-C in Indian population (32). Different findings between the present study and other Indian studies may be due to differences in the age group and different estimation formulae. The Ahmadi, de Cordova and Anandraja formulae were the least accurate at almost all levels of TG. This finding is consistent with the study conducted by Martins J et al., (27).

ROC analysis reconfirmed these findings i.e., Puavillai showed the best performance followed by Martin-Hopkins and then Friedewald’s formula {AUC=0.939 (p<0.001), 0.937 (p<0.001) and 0.934 (p<0.001), respectively}. In terms of correlation, accuracy and diagnostic performance, Ahmadi equation showed the highest misinterpretation with extreme overestimation in this study population similar to the results obtained by Karkhaneh A et al., (33). This finding is contrary to the study performed by Ahmadi SA et al., (7). While Chen, de Cordova, Anandraja and Hattori equations overestimated LDL-C, Vujovic equation underestimated it in most cases. These differences were particularly more at higher TG levels.

Limitation(s)
The present study includes several inherent limitations. Authors had only access to the lipid profiles of the subjects. Clinical outcomes of patients in present study sample were unknown. In addition, we did not have information about intake of cholesterol lowering drugs such as statins. Also, authors did not compare the calculated LDL-C by various formulae with the reference method i.e., ultracentrifugation.

Conclusion

Among the various equations/formulae, Puavillai and Martin-Hopkins showed highest accuracy and better performance than other equations in this study population. Puavillai performed better at very low and very high TG levels (100 mg/dL, >400 mg/dL) when compared to Friedwald’s formula which overestimated LDL-C at all TG levels and the accuracy decreased with increasing TG levels.

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DOI and Others

DOI: 10.7860/JCDR/2022/50590.15903

Date of Submission: May 31, 2021
Date of Peer Review: Aug 15, 2021
Date of Acceptance: Dec 01, 2021
Date of Publishing: Jan 01, 2022

AUTHOR DECLARATION:
• Financial or Other Competing Interests: None
• Was Ethics Committee Approval obtained for this study? Yes
• Was informed consent obtained from the subjects involved in the study? NA
• For any images presented appropriate consent has been obtained from the subjects. NA

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