INTRODUCTION

Sleep is a biobehavioral phenomenon regulated by circadian, homeostatic, and neurohormonal processes.¹A highly significant factor can be derived from the effects of sleep duration: the individual's perception of their sleep quality, that is, the assessment on whether the time the person slept produced a restorative effect.

Lack of sleep exerts deleterious effects on metabolic, endocrine, and immune pathways¹. In recent decades, there has been growing evidence suggesting that too little and too much sleep is associated with adverse health outcomes, including total mortality^2,3, cardiovascular disease, ^3,5-7, type diabetes 2⁸, hypertension ^3,9, and respiratory disorders, obesity in children and adults¹⁰, and self-rated poor health¹¹.

The inability to maintain a normal sleep pattern may involve more than feeling tired the next day, as metabolic control, glucocorticoid production, and blood glucose control are affected¹². In recent years, it has been increasingly shown that suboptimal sleep duration and quality (secondary to the changes demanded by a modern 24-hour society) is significantly associated with diabetes mellitus, insulin resistance (IR), and poor glycemic control^13-15.

The mechanisms that relate short or long sleep duration to the prevalence and severity of DR are not fully understood, although some postulations can be made. Sleep deprivation can be detrimental with respect to DR, as it has been associated with increased levels of ghrelin and leptin (which increases hunger and decreases satiety, and tips the energy balance towards excess¹⁶, as well as insulin resistance and worse glycemic control^14,15.

A pro-inflammatory state induced by sleep deprivation is another possible explanation, since inflammatory biomarkers have also been related to DR^17,18. Rather, sleep disruption may be a consequence of DR. Nighttime melatonin levels were shown to be altered¹⁹. In addition, prolonged sleep duration may promote retinal hypoxia, as rod photoreceptors consume large amounts of energy during darkness by maintaining dark currents, increasing retinal oxygen tension²⁰. It has been suggested that nocturnal oxygen desaturation may induce the expression of vascular endothelial growth factor²¹, which is known to promote DR.

The present research aims to explore the relationship between the perception of sleep quality and the degree of diabetic retinopathy in patients with type 2 Diabetes Mellitus treated in an ophthalmological care service.

METHODS

RESULTS

A total of 50 participants were included in the analysis; 2% (n = 1) with type 1 DM, 48% with type 2 DM (n = 49). According to sex: 48% (n = 24) female and 52% (n = 26) male. The mean age n (SD) was 58.7 (10.1) years. The average age of duration of DM was 15 years. Average weight: 75 kg (16.1) Average height: 1.60 mtr. The DR categories were as follows: Category 1: 24 (48.0%); Category 2: 16 (32.0%); Category 3: 10 (20.0%) The mean duration of sleep (SD) was 7.94 hrs. 6% (n = 3), 40% (n = 20), 54% (n = 27) had short, normal, or long SD respectively; the most frequent degree of education was secondary 36% (n = 18); use of insulin in 32% (n = 16); present smoking 7.4% (n = 2); Average total triglycerides: 257 [77.0, 1200 mg / dl] mg / dl. Average total cholesterol: 209 mg / dl [110.506 mg / dl]. Average glycemia 170.5mg / dl [71.474 mg / dl]. Systolic blood pressure: 131mmHg (19.2mmHg); diastolic blood pressure 78.0mmHg (12.2mmHg); Average HbA1c: 8.29% (2.76%) (table 1).

Other previously reported procedures: Pterygium resection, cataract surgery, application of antiangiogenics, Yag laser, Argon laser, vitrectomy.

Other added ocular conditions found: primary open angle glaucoma, neovascular glaucoma, macular edema, cataract, pterygium.

Other non-ocular conditions reported: hemodialysis, peritoneal dialysis, heart disease and anemia. Of the previous procedures reported and other added ocular conditions mentioned did not present statistical relevance in the initial examinations.

The clinical and demographic characteristics of the study participants stratified by sleep duration are shown intable 2.

Figure 1:  Analysis of cholesterol values in relation to reported hours of sleep 

It can be clearly seen that the statistically significant difference is due to the fact that the subgroup that reported sleeping less than 6 hours only contains 3 patients and of these only 1 has the Cholesterol value present, so the significant difference is spurious (Fig 1).

Figure 2:  Post-hoc analysis of the severity categories of diabetic retinopathy compared to the duration of diabetes 

It can be seen that the statistically significant difference is found in the pair represented by categories 1 and 2 with respect to the reported duration of diabetes.

The significant correlations are mentioned below: Diastolic and Systolic Blood Pressure (0.429), Triglycerides and Total Cholesterol (0.707), HbA1c and Glycemia (0.561), ESS Score and Age (0.394), ESS Score and Weight (0.365), Stop Bang and Age (0.317), Stop Bang and Weight (0.579), Stop Bang and ESS Score (0.452), ISI Score and Stop Bang (0.460) (Fig. 3).

Figure 3:  Correlations between the numerical variables of the study 

Figure 4: Distribution of global values of the Stop Bang Score (A), ISI Score (B) and ESS Score (C) by category of severity of diabetic retinopathy stratified by number of reported hours of sleep. 

As can be seen inFig. 4A, with the data included in this study, a relationship between the severity of diabetic retinopathy, the reported hours of sleep and the global Stop Bang score is not appreciated.

In the results, as with the Stop Bang score, with the data included in this study, a relationship between the severity of diabetic retinopathy, the reported hours of sleep and the global ISI score is not appreciated (Fig. 4B).

Unlike the other two scores, in this case a trend towards an elevation of the ESS score can be seen in the subgroup of patients who reported sleeping 8 hours or more (Fig. 4C), although the trend is not statistically significant. consider that this finding is congruent with the state of the art on the subject of sleep and metabolic condition of retinopathy diabetic patients, it will be necessary to explore this phenomenon in more detail and in a greater number of patients.

DISCUSSION

For the purposes of our study: the quality and quantity of sleep, indirectly evaluated by the daytime sleepiness reported by the patients (ESS Score) shows a tendency to rise in those who reported sleep ranges outside the physiologically appropriate (≥ 8 hrs) , we can also find characteristics of the population consistent with the clinical reality studied, such as the directly proportional correlations between the reported serum levels of triglycerides and total cholesterol, the HbA1c and reported serum glycemia, the ESS score and age and weight, the Stop score Bang and age and weight, the Stop Bang score and the ESS score as well as the ISI score and the Stop Bang. Despite the findings in these correlations, the numerical results are not consistent with them, the authors consider that this phenomenon is due to the limited population sample of the study. Future work will seek to strengthen the size of the population to improve the sample universe in order to clarify the results.

Our study explores a clinical reality in Latin American retinopathy diabetic patients consistent with the scientific literature that has explored and reported similar findings in populations from other geographic regions in the world. Given that, up to the knowledge that the authors have on the subject, this is the first study of these characteristics carried out in a specific Latin American population, it is striking that the trends observed in the results are congruent with that reported by other authors in other geographic regions. worldwide.

Good control of blood glucose and other systemic risk factors such as hypertension and hyperlipidemia are the main objective for the prevention of ocular complications in diabetes mellitus. The authors consider it important to integrate the assessment of sleep quality in the retinopathy diabetic patient to strengthen the care strategy, in collaboration with experts in lifestyle medicine. The data suggest that optimization of the duration and quality of sleep should be tested as an intervention to improve glucose control in patients with type 2 diabetes.

The limitations of the study lie mainly in the small sample size, which could limit the statistical power to find some associations. However, given the nature of the study, the results are of great importance. As future work, the authors propose to increase the sample size significantly, as well as the subgroups in the same representative of the intervals of reported hours of sleep.

CONCLUSION

Although the trends are not statistically significant, the authors consider that this finding is congruent with the state of the art on the subject of sleep and metabolic condition of retinopathic diabetic patients (trend of elevated ESS score reported in the subgroup of 8 or more hours of sleep ), it will be necessary to explore this phenomenon in more detail and in a larger number of patients.