ClinicalTrials.gg
CompletedNCT03387306Updated Jan 2, 2018

Serum Bilirubin Levels in Normal-tension Glaucoma

An observational study in Normal Tension Glaucoma and Bilirubin; Defect, Excretion, sponsored by Trakya University. Completed at 1 site in Turkey. Open to participants aged 18 Years to 80 Years. Per ClinicalTrials.gov, last updated 2018-01-02.

Sponsored by Trakya University · Observational

Study type
Observational
Model
Case-control
Time perspective
Retrospective
Enrollment
76
Ages
18 Years to 80 Years
Sex
All
01

Study summary

Purpose: To analyze the relationship between normal-tension glaucoma (NTG) and serum bilirubin levels.

Materials and Methods: This research included 38 patients with NTG and 38 healthy controls with similar age and sex distribution, for a total of 76 subjects. Serum samples were taken from all of the subjects, direct serum bilirubin, indirect serum bilirubin and the total serum bilirubin were measured.

Read the detailed description

This is a retrospective study of cases with recently or previously diagnosed NTG who were admitted to our clinic between 2010 and 2017. This study included 38 patients with NTG and 38 healthy controls with similar age and sex distribution, for a total of 76 subjects. Written informed consent was obtained from all of the participants. The study was approved by the institutional review board of the hospital and adhered to the tenets of the Declaration of Helsinki.

A complete ophthalmic examination including best-corrected visual acuity, slit-lamp biomicroscopy, Goldmann applanation tonometry (AT 900, Haag-Streit Diagnostics, Koeniz, CH), corneal thickness evaluation (Pachymeter SP-3000, Tomey Corporation, Nagoya, JP), gonioscopy and ophthalmoscopy was performed in all NTG cases. Additionally, optical coherence tomography (OCT RS-3000 Lite, NIDEK Corporation, Tokyo, JP) measurement of the peripapillary retinal nerve fibre layer thickness, and Humprey visual field testing (Carl-Zeiss Meditec, Dublin, CA) were also performed.

NTG was diagnosed based on a clinical examination showing a normal IOP (corrected for corneal thickness), thinning of the peripapillary retinal nerve fibre layer, optic nerve damage, and characteristic glaucomatous visual field defects. The exclusion criteria included other forms of glaucoma such as primary open-angle glaucoma, primary closed-angle glaucoma, pigmentary glaucoma and exfoliative glaucoma. Patients who had active systemic diseases such as those affecting the liver, biliary system, pancreas and kidney and infectious diseases or malignant tumours that could influence the serum bilirubin concentrations were also excluded.

Fasting blood samples were taken from each participant to measure direct bilirubin, indirect bilirubin, and the total serum bilirubin concentrations. The direct bilirubin and total bilirubin concentrations were measured with an Architect C16000 Clinical Chemistry Analyzer (Abbott Laboratories, Abbott Park, IL, USA), using its original kits, and the indirect bilirubin concentrations were calculated by the following formula: indirect bilirubin = total bilirubin - direct bilirubin.

All the data were compiled into a computer file, and Statistical Package for Social Sciences for Windows 22.0 was used to perform the statistical analysis. Student's t test or the Mann-Whitney U test were used to compare the mean values between the two groups, after the evaluation of the data for a normal distribution using the Kolmogorov-Smirnov test. A p value less than 0.05 was considered statistically significant.

02

Conditions studied

  • Normal Tension Glaucoma
  • Bilirubin; Defect, Excretion

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Keywords

  • serum bilirubin
  • normal-tension glaucoma
  • oxidative stress
03

In context

Low Tension Glaucoma

65 studies on the registry are indexed under Low Tension Glaucoma; 10 are open to participants now.

This study's enrollment of 76 is below the median of 94 across 32 observational studies indexed under Low Tension Glaucoma.

Browse Low Tension Glaucoma studies →

Lead sponsor

Trakya University is the lead sponsor of 155 studies on the registry; 15 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 80 Years
Sexes eligible
All
Sampling method
Probability sample

Study population

NTG was diagnosed based on a clinical examination showing a normal IOP (corrected for corneal thickness), thinning of the peripapillary retinal nerve fibre layer, optic nerve damage, and characteristic glaucomatous visual field defects. The exclusion criteria included other forms of glaucoma such as primary open-angle glaucoma, primary closed-angle glaucoma, pigmentary glaucoma and exfoliative glaucoma. Patients who had active systemic diseases such as those affecting the liver, biliary system, pancreas and kidney and infectious diseases or malignant tumours that could influence the serum bilirubin concentrations were also excluded.

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  • Healthy volunteers

Exclusion criteria

Exclusion Criteria:

  • Patients who had active systemic diseases such as those affecting the liver, biliary system, pancreas and kidney and infectious diseases or malignant tumours that could influence the serum concentrations were excluded.
Terms in these criteria, in plain language(1)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

Bilirubin

A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.

Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.

05

Study design

Observational model
Case-control
Time perspective
Retrospective
Enrollment
76 participants (actual)
Patient registry
No

Groups and cohorts

  • Patient group

    This grup included 38 patients with NTG.

  • Control group

    This group included 38 healthy controls.

06

What researchers measure

Primary outcomes

  1. Serum Bilirubin Levels

    Serum indirect, direct and total bilirubin levels

    Time frame: January 2017-March 2017

07

Study locations

1 site
  • Sadık Altan Ozal
    Edirne, In The USA Or Canada, Please Select... 22030, Turkey
08

References and documents

Publications

  • Tham YC, Li X, Wong TY, Quigley HA, Aung T, Cheng CY. Global prevalence of glaucoma and projections of glaucoma burden through 2040: a systematic review and meta-analysis. Ophthalmology. 2014 Nov;121(11):2081-90. doi: 10.1016/j.ophtha.2014.05.013. Epub 2014 Jun 26. PubMed 24974815 ↗
  • Flammer J, Mozaffarieh M. What is the present pathogenetic concept of glaucomatous optic neuropathy? Surv Ophthalmol. 2007 Nov;52 Suppl 2:S162-73. doi: 10.1016/j.survophthal.2007.08.012. PubMed 17998042 ↗
  • Mallick J, Devi L, Malik PK, Mallick J. Update on Normal Tension Glaucoma. J Ophthalmic Vis Res. 2016 Apr-Jun;11(2):204-8. doi: 10.4103/2008-322X.183914. PubMed 27413503 ↗
  • Cho HK, Kee C. Population-based glaucoma prevalence studies in Asians. Surv Ophthalmol. 2014 Jul-Aug;59(4):434-47. doi: 10.1016/j.survophthal.2013.09.003. Epub 2014 May 13. PubMed 24837853 ↗
  • Iwase A, Suzuki Y, Araie M, Yamamoto T, Abe H, Shirato S, Kuwayama Y, Mishima HK, Shimizu H, Tomita G, Inoue Y, Kitazawa Y; Tajimi Study Group, Japan Glaucoma Society. The prevalence of primary open-angle glaucoma in Japanese: the Tajimi Study. Ophthalmology. 2004 Sep;111(9):1641-8. doi: 10.1016/j.ophtha.2004.03.029. PubMed 15350316 ↗
  • Cursiefen C, Wisse M, Cursiefen S, Junemann A, Martus P, Korth M. Migraine and tension headache in high-pressure and normal-pressure glaucoma. Am J Ophthalmol. 2000 Jan;129(1):102-4. doi: 10.1016/s0002-9394(99)00289-5. PubMed 10653426 ↗
  • Henry E, Newby DE, Webb DJ, O'Brien C. Peripheral endothelial dysfunction in normal pressure glaucoma. Invest Ophthalmol Vis Sci. 1999 Jul;40(8):1710-4. PubMed 10393040 ↗
  • Himori N, Kunikata H, Shiga Y, Omodaka K, Maruyama K, Takahashi H, Nakazawa T. The association between systemic oxidative stress and ocular blood flow in patients with normal-tension glaucoma. Graefes Arch Clin Exp Ophthalmol. 2016 Feb;254(2):333-41. doi: 10.1007/s00417-015-3203-z. Epub 2015 Oct 30. PubMed 26514963 ↗
  • Yuki K, Murat D, Kimura I, Ohtake Y, Tsubota K. Reduced-serum vitamin C and increased uric acid levels in normal-tension glaucoma. Graefes Arch Clin Exp Ophthalmol. 2010 Feb;248(2):243-8. doi: 10.1007/s00417-009-1183-6. Epub 2009 Sep 8. PubMed 19763599 ↗
  • Harada T, Harada C, Nakamura K, Quah HM, Okumura A, Namekata K, Saeki T, Aihara M, Yoshida H, Mitani A, Tanaka K. The potential role of glutamate transporters in the pathogenesis of normal tension glaucoma. J Clin Invest. 2007 Jul;117(7):1763-70. doi: 10.1172/JCI30178. PubMed 17607354 ↗
  • Gupta N, Singh T, Chaudhary R, Garg SK, Sandhu GS, Mittal V, Gupta R, Bodin R, Sule S. Bilirubin in coronary artery disease: Cytotoxic or protective? World J Gastrointest Pharmacol Ther. 2016 Nov 6;7(4):469-476. doi: 10.4292/wjgpt.v7.i4.469. PubMed 27867680 ↗
  • Kapitulnik J. Bilirubin: an endogenous product of heme degradation with both cytotoxic and cytoprotective properties. Mol Pharmacol. 2004 Oct;66(4):773-9. doi: 10.1124/mol.104.002832. Epub 2004 Jul 21. No abstract available. PubMed 15269289 ↗
  • Liao SL. The role of bilirubin and phototherapy in the oxidative/antioxidant balance. Pediatr Neonatol. 2015 Apr;56(2):77-8. doi: 10.1016/j.pedneo.2015.01.001. Epub 2015 Jan 22. No abstract available. PubMed 25735960 ↗
  • Wu TW, Fung KP, Wu J, Yang CC, Weisel RD. Antioxidation of human low density lipoprotein by unconjugated and conjugated bilirubins. Biochem Pharmacol. 1996 Mar 22;51(6):859-62. doi: 10.1016/0006-2952(95)02395-x. PubMed 8602883 ↗
  • Cao L, Xue L, Luo DM. Lower serum bilirubin concentration in patients with migraine. Int J Clin Exp Med. 2015 Aug 15;8(8):13398-402. eCollection 2015. PubMed 26550273 ↗
  • Vitek L, Jirsa M, Brodanova M, Kalab M, Marecek Z, Danzig V, Novotny L, Kotal P. Gilbert syndrome and ischemic heart disease: a protective effect of elevated bilirubin levels. Atherosclerosis. 2002 Feb;160(2):449-56. doi: 10.1016/s0021-9150(01)00601-3. PubMed 11849670 ↗
  • Peng F, Deng X, Yu Y, Chen X, Shen L, Zhong X, Qiu W, Jiang Y, Zhang J, Hu X. Serum bilirubin concentrations and multiple sclerosis. J Clin Neurosci. 2011 Oct;18(10):1355-9. doi: 10.1016/j.jocn.2011.02.023. Epub 2011 Jul 22. PubMed 21782448 ↗
  • Demir M, Demir C, Keceoglu S. Relationship between serum bilirubin concentration and nondipper hypertension. Int J Clin Exp Med. 2014 May 15;7(5):1454-8. eCollection 2014. PubMed 24995111 ↗
  • Tanindi A, Erkan AF, Alhan A, Tore HF. Arterial stiffness and central arterial wave reflection are associated with serum uric acid, total bilirubin, and neutrophil-to-lymphocyte ratio in patients with coronary artery disease. Anatol J Cardiol. 2015 May;15(5):396-403. doi: 10.5152/akd.2014.5447. Epub 2014 Jun 3. PubMed 25430407 ↗

Individual participant data

Plan to share: No

09

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reached

Ran from Jan 2010 to primary completion in Mar 2017, 86 months.

How these figures are worked out, and which studies are left out of them.

Registered
Dec 21, 2017
First posted
Jan 2, 2018
StartActual
Jan 2010
Primary completionActual
Mar 2017
CompletionActual
Apr 2017
Last update
Jan 2, 2018
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Jan 2, 2018, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT03387306
Lead sponsor
Trakya University
Responsible party
Sadık Altan Ozal (Assistant of Proffessor, Trakya University) — Principal investigator
First posted
Jan 2, 2018
Start date
Jan 2010
Primary completion
Mar 2017
Completion
Apr 2017
Last update
Jan 2, 2018

Study contacts

Sadık Altan Ozal
principal investigator · Trakya University

Oversight

Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

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This study is completed, as verified in Dec 2017. You cannot join it, but the record below documents what was studied.

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