Diabetic Retinopathy and Its Effect on Quality of Life: An Original Research.

INTRODUCTION: Diabetes is associated with the vascular and the neuronal damage of the eye leading to diabetic retinopathy (DR). The circadian rhythms and also the quality of life (QoL) are known to be impacted by the photosensitive retinal ganglion cells, which are seen to be affected in the DR. Hence, we aim to find a relation between the DR and its impact on the life quality.
MATERIALS AND METHODS: Thousand participants were equally divided into two groups of case and controls (DR). The control group was further divided into three subgroups based on the severity of the disease as proliferative and nonproliferative (mild, moderate, and severe). The impact on the QoL was assessed using the Short Form Health Survey-36. The collected data were analyzed for the various grades of the severity of DR on the quality of the life.
RESULTS: There was a notable change between the case and the controls and the QoL deteriorated with the severity of the disease. However, these findings were insignificant statistically.
CONCLUSION: DR impacts the QoL of the patients, and the severity of the disease is proportional to the worsening of the disease. Further, research is warranted for the association. Copyright:

INTRODUCTION

Diabetes mellitus is one of the diseases that is on a constant rise both in the developed and developing nations. The complication of the visual impairment caused due to the vascular and neural involvement in the diabetes is diabetic retinopathy (DR).[1] Early identification of the retinopathy is possible even before the symptoms are noticed by the patient, with the ophthalmic examinations done as early as 6 months of the diagnosis of the disease.[2] In the animal studies done by Olivares et al.,[3] retinal cell damage was identified in the diabetics. Retinal ganglionic cell loss was seen in the study of Ng et al.[4] where the damage leads to loss of the eye sight. Various previous studies with varying degree of results have shown that diabetes leads to the damage of the photosensitive retinal ganglionic cells and the damage is proportional to the disease severity.[567891011] These photosensitive retinal ganglionic cells are essential for the circadian rhythms in the body.[12] In the event, these cells are damaged the daily activities like the sleep cycle is derailed, which could lead to a cascade of other events such as depression, etc., In the diabetes based on the severity of the photosensitive retinal ganglionic cells, these events are expected. Studies have shown an association between the insufficient sleep and the onset of the DR. In the previous researches, inadequate sleep and the impact on the immunity and inflammation are established.[1314] Impaired immunity is in turn known for the pathogenesis of the DR. Sleep, immunity, and diabetes are all independent risk factors for each other, and all these are known to impact the quality of life (QoL).[151617] The insulin resistance and the sleep quality have been shown associated with the pathogenesis of the diabetes type 2.[181920] Nevertheless, the association between the pRGC, DR, and the sleep patterns was not reported in these studies. Furthermore, in these studies, the preexisting conditions such as sleep apnea and obesity were not considered for the sleep disturbances seen in the DR various stages.[2122] Our study is one of the first studies to evaluate the impact of the various severities of DR on the sleep and in turn on the QoL of the patients.

MATERIALS AND METHODS

In our study, thousand participants were selected between the age group of 18–75 years. The study was conducted for a period of 1 year from 2019 to 2020. The participants were divided into two groups of healthy controls with a 6/6 vision and cases with the diagnosed diabetes mellitus and retinopathy. Basic demographics were recorded. The participants with any pre-existing eye disease with/without retinal damage, on medication, known sleep disorders, alcoholics, and night shift workers were excluded from the study. After receiving the Institutional Ethical Clearance and the informed consent from the patients, the ophthalmic examinations were done to establish the grade of DR based on the “International clinical diabetic retinopathy disease severity scale” [Table 1].

Table 1

Various grades seen in the diabetic retinopathy

Clinical features	Grade of the diabetic retinopathy
Only microaneurysms present	Moderate
More than microaneurysm, but lower than non-PDR	Moderate
Minimum one is seen: In all the quadrants, widespread >20 hemorrhages (intraretinal), venous beading in 2+ quadrants, IRMA in 1+ quadrant, absence of PDR	Severe
Neovascularization +/− vitreous/preretinal hemorrhage	Proliferative

IRMA: Intraretinal microvascular abnormalities, PDR: Proliferative diabetic retinopathy

The Pittsburgh Sleep Quality Index was used to assess the sleep pattern among the subjects.[23] The QoL is assessed by the self-reported questionnaires using the Short Form Health Survey.[24] There were eight aspects of the survey that were covered such as general health, social, physical, emotional functioning, pain and fatigue, and inadequacy due to emotional and physical problems. The obtained data were analyzed using the IBM Corp. Released 2020. IBM SPSS Statistics for Windows, Version 27.0. Armonk, NY: IBM Corp keeping the P < 0.05 as significant.

RESULTS

We observed that there was no significant difference among the two groups when the genders and age were compared; however, the participants in the case group were older than the controls. Within the grades of the DR, no significant difference was observed between the genders distributions; however, there was significant difference in the age distribution. No significant variation was seen between the two groups and among the various grades of DR when the sleep index was compared. The comparable results were obtained when the emotional limitation, energy/fatigue, pain, and social functioning were compared between the case and the control groups. All the domains in the QoL index were comparable with no significant differences between the various grades in DR. However, in the general health, significant variation was observed between the groups (P < 0.0001) and also within the grades of the DR (P = 0.045). Physical functioning, physical limitations, and emotional well-being were the aspects of QoL that were showed significant variations between the case and the control groups. Higher mean scores were obtained in all the domains of the QoL for the DR subjects except for the emotional well-being when the cases and the controls were compared [Table 2].

Table 2

Comparison of variables between the case and control groups and among the various grades of diabetic retinopathy

Variable	Cases	Controls	P	Mild	Moderate/severe	PDR	P
Basic demographics
Males, n	294	326	NS	102	91	92	NS
Females, n	206	174	NS	73	59	63	NS
Age	56	48.2	NS	59.81 (14.35)	55.13 (11.59)	64.12 (12.85)	<0.001
PSQI, n (%)
>5	162 (37.51)	121 (39.61)	NS	60 (39.31)	55 (41.91)	46 (31.81)	NS
>10	68 (15.511)	37 (11.881)	NS	24 (20.911)	25 (17.831)	20 (12.578)	NS
Quality of life, mean (SD)
Energy/fatigue	61.812 (18.811)	62.612 (19.441)	NS	64.530 (17.680)	60.195 (19.231)	60.661 (19.330)	NS
General health	56.513 (22.841)	71.771 (19.411)	<0.0001	60.250 (21.701)	56.92 (22.710)	52.575 (23.661)	0.045
Physical limitations	77.214 (36.841)	89.271 (36.871)	<0.0001	81.181 (32.611)	79.651 (34.630)	71.369 (41.870)	NS
Physical functioning	75.610 (26.813)	86.513 (20.241)	<0.0001	77.930 (24.211)	77.211 (25.020)	72.125 (30.360)	NS
Emotional limitation	92.612 (22.091)	90.541 (25.219)	NS	92.121 (21.718)	93.491 (20.521)	92.278 (23.865)	NS
Pain	79.810 (23.771)	81.721 (21.851)	NS	88.30 (21.251)	88.481 (21.740)	83.420 (25.158)	NS
Emotional well-being	82.811 (14.271)	76.161 (16.671)	<0.0001	84.421 (13.402)	81.495 (14.482)	82.251 (14.890)	NS
Social functioning	86.17 (22.871)	88.201 (19.891)	NS	81.020 (22.130)	79.571 (25.880)	78.877 (23.690)	NS

PDR: Proliferative diabetic retinopathy, PSQI: Pittsburgh sleep quality index, SD: Standard deviation, NS: Not significant

DISCUSSION

The present study is one of the firsts to evaluate the impact of the DR on the QoL, while comparing for the various grades of the diseases. Furthermore, contrary to the previous studies in the present study, the factors influencing the outcomes were excluded like the pre-existing health conditions that might impact the sleep, depression, medications, etc. When compared to other studies, the sample size was larger with almost uniform distribution of the genders and the ages. In our study, we have evaluated the relationship between the DR and the QoL based on the sleep quality, which was not thoroughly established in the previous literatures.[19202122] In our study, it was observed that there was no significant difference in the QoL based on the sleep quality for the various grades of the DR. Similar observations were noted in the study done by Jee et al.[20] where they could not find a significant association between the DR and the sleep quality. Similarly, in the study of Tan et al.[22] in a large sample similar to the present study, DR and its impact on the sleep quality and quantity were studied. However, they were not evaluated for the various grades of the DR. This aspect was addressed in the present study. However, there were no significant changes observed with severity of the DR and between the groups. This finding proposes that the retinal glial cells and their effect on the circadian rhythm may not influence the sleep quality and hence the QoL in the DR. Similar suggestions were made in the study of Meng et al.[21] where they noted association of sleep and the DR in a small cohort. We observed in our study that the DR group had a higher mean age than the control group showing that the onset of the DR occurs at an older age.[25] Bjorvatn et al.[26] in their study stated that in the absence of the sleep apnea, the sleep quality may be a factor of the BMI rather than the DR. Nevertheless, in our present study, the preexisting sleep conditions were excluded. In a study of Lamond et al.,[27] the quality of the sleep was impaired in the DR group that was associated with the various complications of the disease rather than a due to the dysfunction of the pRGCs. Comparable pain scores were established between the groups and grades in our study. The comparable results were obtained when the emotional limitation, energy/fatigue, pain, and social functioning were compared between the case and the control groups. All the domains in the QoL index were comparable with no significant differences between the various grades in DR. The only domain of the QoL that showed a significant change between the groups and the severity of the DR was the general health. We purposely limited our examination to the individuals who did not have a known sleep or mood disorder. Although, in two previous studies, poor sleep was significantly associated with the diabetics; however, the other confounding factors were not addressed.[28] It is conceivable that our exacting exclusion criteria may have prompted sample bias of an group of resilient DR subjects. In any case, these measures were fundamental to unravel the possible effect of DR, thought to be identified with pRGCs loss, instead of components irrelevant to pRGCs functional role. We additionally did not have any severely affected subjects that might have led to the present result. Another method of surveying pRGC work is pupillary reactions; Feigl et al.[6] recognized a pattern for debilitated pRGC work in DR in their information. No proof was seen in our study to propose that with the DR severity sleep quality was impacted that might have been due to pRGCs dysfunction. This would be normal dependent on the visual acuities of most of our DR members. The various tests advised to assess the pRGC integrity were not performed in our study.[29] The quantity of pRGCs needed to support circadian rhythms isn't known. There are no data in humans relating the pRGC function. Further examinations contrasting people and PDR incorporating those with severe visual defects ought to think about functionality. Nonetheless, few anomalies in sleep in our study group were expected as there is proof to recommend that diabetes prompts morphological changes in pRGCs, altering the circadian rhythms, along with delayed entrainment.[7] The duration of the diabetes was not enquired in the present study that is known influence the DR. This might have impacted the outcome in our study. The severe grade and PDR, of the DR were expected to have sleep disturbance and hence poor QoL. Although similar results were seen, they were not significant. All the scores obtained were through the self-reported. We did not consider the entrainment in our cohort. HbA1c levels have been associated with sleep pattern changes, and the blood glucose levels also have been associated with the incidence of DR.[30] Although we did not gauge HbA1c, future examinations ought to consider it. To observe a change in the circadian rhythm without the visual impairment in DR is difficult.[7] More progressive stages of the diabetes such as the diabetic neuropathy were also not considered in our study.

CONCLUSION

The results of our study conclude that there was no impact of the DR on the QoL in those with good visual function. It is conceivable that pRGCs role has not been adequately undermined to affect patients sleep quality. The effect of the sleep and the consequently on the QoL might be expected in the patients with the sight loss and the associated retinal tissue and glial cell damages. Further investigations in this particular cohort would be needed to affirm this.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.