Using Mixed Models with Flexible Random Effects for Determining the Best Diabetic Macular Edema Treatment

Document Type : Original Article (s)

Authors

1 PhD student, Department of Biostatistics, Tarbiat Modares University, Tehran, Iran

2 Professor, Department of Biostatistics, Tarbiat Modares University, Tehran, Iran

3 Assistant Professor, Department of Statistics, Isfahan University, Isfahan, Iran

4 Assistant Professor, School of Paramedical Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran

5 Professor, Department of Ophthalmologist, Shahid Beheshti University of Medical sciences, Tehran, Iran

Abstract

Background: Diabetic macular edema is one of the most prevalent outcomes between diabetic patients. According to high prevalence of this disorder and its related outcomes between diabetic patients, the goal of this study is determining the efficacy of a single intravitreal injection of bevacizumab (IVB) alone or in combination with triamcinolone versus macular laser photocoagulation (MPC) as primary treatment for diabetic macular edema (DME) using updated statistical modelling.Methods: This modeling was performed on 102 diabetic patients in three above-mentioned groups who had diabetic macular edema and did not get any treatment before the beginning of clinical trials. A mixed model with non-normal random effects has been proposed to compare the effects of treatment on diabetic macular edema by omitting the effects of confounders. Effect of these treatments has been investigated according to variation of best-corrected Visual Acuity and central macular thickness, as two major outcomes.Finding: The results of mixed modelling with non-normal random effects according to omitting the effects of confounders in the period of study, show that the Intravitreal Bevacizumab injection alone or combined with Triamcinolone treatments have more Therapeutic effect than the Macular Photocoagulation treatment on Diabetic Macular Edema patients.Conclusion: According to this investigation, patients with more diabetic duration who had more central macular tickness and less best-corrected visual acuity in the beginning of the study had better response to interventions. More investigations showed using different treatments lead to different results on diabetic macular edema.

Keywords


  1. Rodriguez J, Sanchez R, Munoz B, West SK, Broman A, Snyder RW, et al. Causes of blind-ness and visual impairment in a population-based sample of U.S. Hispanics. Ophthalmology 2002; 109(4): 737-43.
  2. Jamal-u-Din, Qureshi MB, Khan AJ, Khan MD, Ahmad K. Prevalence of diabetic retinopathy among individuals screened positive for diabetes in five community-based eye camps in northern Karachi, Pakistan. J Ayub Med Coll Abbottabad 2006; 18(3): 40-3.
  3. Rema M, Deepa R, Mohan V. Prevalence of retinopathy at diagnosis among type 2 diabetic patients attending a diabetic centre in South In-dia. Br J Ophthalmol 2000; 84(9): 1058-60.
  4. King H, Aubert RE, Herman WH. Global burden of diabetes, 1995-2025: prevalence, numerical estimates, and projections. Diabetes Care 1998; 21(9): 1414-31.
  5. Harney F. Diabetic retinopathy. Medicine Ab-ingdon 2006; 34(3): 95-8.
  6. Kernell A, Dedorsson I, Johansson B, Wickstrom CP, Ludvigsson J, Tuvemo T, et al. Prevalence of diabetic retinopathy in children and adolescents with IDDM. A population-based multicentre study. Diabetologia 1997; 40(3): 307-10.
  7. National Society to Prevent Blindness. Visual Problems in the US Data Analysis Definitions, Data Sources, Detailed Data Tables, Analysis, Interpretation. New York: 1980.
  8. Klein R, Klein BE, Moss SE. Visual impairment in diabetes. Ophthalmology 1984; 91: 1-9.
  9. Hardy RA, Crawford JB. Retina. In: Vaughn D, Asbury T, iordan-Eva P, editors. General Oph-thalmology. 15th ed. Stamford: Appleton & Lange; 1999. p. 178-99.
  10. Diggle PJ, Heagerty PJ, Liang KY, Zeger SL. Analysis of Longitudinal Data. 2nd ed. Oxford University Press; 2002.
  11. Davis CS. Statistical Methods for the Analysis of Repeated Measurements. Springer Texts in Sta-tistics. New York: Springer; 2002.
  12. Timm, N. H. Applied Multivariate Analysis. Springer-Verlag, New York. Laird, N. M. and Ware, J. H., Random Effects Models for Longi-tudinal Data. Biometrics 1982; 38: 963-74.
  13. Muller KE, Stewart PW. Linear model: Univari-ate, Multivariate, and Mixed Models. New Jer-sey: John Wiley & Sons; 2006.
  14. Fitzmaurice G, Davidian M, Verbeke G, Mo-lenberghs G. Handbooks of Modern Statistical Methods: Longitudinal Data Analysis. New York: Taylor & Francis Group; 2009.
  15. Soheilian M, Ramezani A, Obudi A, Bijanzadeh B, Salehpour M, Yaseri M, et al. Randomized Trial of Intravitreal Bevacizumab Alone or Combined with Triamcinolone versus Macular Photocoagulation in Diabetic Macular Edema. American Academy of Ophthalmology; 2009.
  16. Laird NM, Ware JH. Random Effects Models for Longitudinal Data. Biometrics 1982; 38(963): 974.
  17. Azzalini A. A class of distributions which in-cludes the normal ones. Scand Actuar J 1985; 12(171): 178.
  18. Azzalini A, Dal-Cappello T, Kotz S. Log-skew-normal and log-skew-t distributions as models for family income data. Journal Income Distri-bution 2003; 11: 12-20.
  19. Spiegelhalter D, Thomas A, Best N, Lunn D. WinBUGS User Manual, Version 1.4. MRC Bio-statistics Unit, Institute of Public Health and De-partment of Epidemiology & Public Health, Im-perial College School of Medicine. Available from: URL: http://www.mrc.bsu.cam.ac.uk/bugs.
  20. Jonas JB, Kamppeter BA, Harder B, Voss-merbaeumer U, Sauder G, Spandau UH. Intravi-treal triamcinolone acetonide for diabetic macu-lar edema: a prospective, randomized study. J Ocul Pharmacol Ther 2006; 22(3): 200-7.
  21. Chun DW, Heier JS, Topping TM, Duker JS, Bankert JM. A pilot study of multiple intravitreal injections of ranibizumab in patients with center-involving clinically significant diabetic macular edema. Ophthalmology 2006; 113(10): 1706-12.
  22. Audren F, Erginay A, Haouchine B, Benosman R, Conrath J, Bergmann JF, et al. Intravitreal tri-amcinolone acetonide for diffuse diabetic macu-lar oedema: 6-month results of a prospective controlled trial. Acta Ophthalmol Scand 2006; 84(5): 624-30.
  23. Gillies MC, Sutter FK, Simpson JM, Larsson J, Ali H, Zhu M. Intravitreal triamcinolone for refrac-tory diabetic macular edema: two-year results of a double-masked, placebo-controlled, random-ized clinical trial. Ophthalmology 2006; 113(9): 1533-8.