Management of diabetes mellitus in older people with comorbidities

It was with great interest that we read the paper by Prof. Huang.1 In our opinion the author does not emphasize on the relative impact of specific ocular complications, namely on Diabetic Retinopathy.
We would like to draw attention on diabetic retinopathy, as a comorbidity factor of paramount importance.
The incidence of legal blindness among diabetics is 25 fold that of non diabetics.2, 3 In the developed world, diabetic retinopathy is the leading cause of legal blindness in individuals over 40 years old, while in the US alone diabetic retinopathy is responsible for 12% of new cases of legal blindness annually.2 According to the Wisconsin Epidemiologic Study of Diabetic Retinopathy, after 20 years with the disease, nearly all the patients suffering from Diabetes Type I and 60% of patients with Diabetes Type II, present with Diabetic Retinopathy that is potentially sight threatening.4, 5 Moreover, diabetic patients often neglect the need for ophthalmologic monitoring6. In a study by Witkin et al.7, approximately 26% of the < 30 years old at onset and 36% of the >30 years old at onset diabetic population had never had an ophthalmologic examination. In the same study 11% of the < 30 years old at onset and 7% of the >30 years old at onset individuals with high-risk characteristics for severe visual loss according to Diabetic Retinopathy Study, had never been examined or were examined by an ophthalmologist for more than two years.
Visual impairment may have a multidimensional impact on patients. Conditions such as dementia or hypoglycemia, extremely common in elderly diabetic patients, are directly influenced by the diminished ability of the patient to perceive visual information, while the frequency of the development and/or progression of retinopathy increase significantly with age.8
More specifically, visual impairment due to diabetic retinopathy may:
• Contribute significantly to functional impairment and the ability to maintain an adequate level of self care 9 (receiving medication timely and correctly, self monitoring blood glucose levels, taking proper action in case of hypoglycemia).
• Impair the activities of daily living (ADLs), as well as any type of physical activity and thus being an independent morbidity factor.10
• Has an overall negative impact on Quality of Life. From the patient’s perspective, any therapy should aim to make his life longer and better. Health related Quality of life, not currently measured in the majority of clinical trials, is closely correlated to the visual function.11, 12
• Decreased vision may spark a vicious circle of depression and cognitive impairment by the loss of control over important everyday activities, loss of independence, deprivation of stimulating visual information (reading, watching a TV broadcast, socializing).13, 14
Based on the above, we strongly believe that moving towards an individualized approach to older diabetic patients, and actively involving this sensitive population in their treatment could be greatly benefited by focusing on the early detection and treatment of diabetic retinopathy, as well as the use of new therapeutic modalities, namely the anti-vascular endothelial growth factor (anti-VEGF) agents.

References
1. Huang ES. Management of diabetes mellitus in older people with comorbidities. BMJ (Clinical research ed.). 2016;353:i2200
2. Kahn HA, Hiller R. Blindness caused by diabetic retinopathy. American journal of ophthalmology. 1974;78:58-67
3. Palmberg PF. Diabetic retinopathy. Diabetes. 1977;26:703-709
4. Klein R, Klein BE, Moss SE, Davis MD, DeMets DL. The wisconsin epidemiologic study of diabetic retinopathy. Ii. Prevalence and risk of diabetic retinopathy when age at diagnosis is less than 30 years. Archives of ophthalmology (Chicago, Ill. : 1960). 1984;102:520-526
5. Klein R, Klein BE, Moss SE, Davis MD, DeMets DL. The wisconsin epidemiologic study of diabetic retinopathy. Iii. Prevalence and risk of diabetic retinopathy when age at diagnosis is 30 or more years. Archives of ophthalmology (Chicago, Ill. : 1960). 1984;102:527-532
6. Will JC, German RR, Schuman E, Michael S, Kurth DM, Deeb L. Patient adherence to guidelines for diabetes eye care: Results from the diabetic eye disease follow-up study. American journal of public health. 1994;84:1669-1671
7. Witkin SR, Klein R. Ophthalmologic care for persons with diabetes. Jama. 1984;251:2534-2537
8. Kato S, Takemori M, Kitano S, Hori S, Fukushima H, Numaga J, et al. Retinopathy in older patients with diabetes mellitus. Diabetes research and clinical practice. 2002;58:187-192
9. Crews JE, Chou CF, Zhang X, Zack MM, Saaddine JB. Health-related quality of life among people aged >/=65 years with self-reported visual impairment: Findings from the 2006-2010 behavioral risk factor surveillance system. Ophthalmic epidemiology. 2014;21:287-296
10. Fisher DE, Jonasson F, Klein R, Jonsson PV, Eiriksdottir G, Launer LJ, et al. Mortality in older persons with retinopathy and concomitant health conditions: The age, gene/environment susceptibility-reykjavik study. Ophthalmology. 2016
11. Hariprasad SM, Mieler WF, Grassi M, Green JL, Jager RD, Miller L. Vision-related quality of life in patients with diabetic macular oedema. The British journal of ophthalmology. 2008;92:89-92
12. Davidov E, Breitscheidel L, Clouth J, Reips M, Happich M. Diabetic retinopathy and health-related quality of life. Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie. 2009;247:267-272
13. Sturrock BA, Xie J, Holloway EE, Hegel M, Casten R, Mellor D, et al. Illness cognitions and coping self-efficacy in depression among persons with low vision. Investigative ophthalmology & visual science. 2016;57:3032-3038
14. Court H, McLean G, Guthrie B, Mercer SW, Smith DJ. Visual impairment is associated with physical and mental comorbidities in older adults: A cross-sectional study. BMC medicine. 2014;12:181