Improved glycemic control and cardiovascular risk in patients with diabetes mellitus Type II following cataract phacoemulsification surgery

Maria João Matias; Pedro Alves-Peixoto; António Rocha; João Chibante-Pedro

doi:10.4103/pajo.pajo_58_22

ORIGINAL ARTICLE

Year : 2023 | Volume : 5 | Issue : 1 | Page : 7

Improved glycemic control and cardiovascular risk in patients with diabetes mellitus Type II following cataract phacoemulsification surgery

Maria João Matias¹, Pedro Alves-Peixoto², António Rocha¹, João Chibante-Pedro¹
¹ Department of Ophtalmology of the Centro Hospitalar de Entre o Douro e Vouga, Street Cândido Pinho, Santa Maria da Feira, Portugal
² Rovisco Pais Physical Medicine and Rehabilitation Center, Rovisco Pais, Portugal

Date of Submission	12-Oct-2022
Date of Decision	14-Oct-2022
Date of Acceptance	20-Oct-2022
Date of Web Publication	27-Mar-2023

Correspondence Address:
Maria João Matias
Department of Ophtalmology, Centro Hospitalar De Entre O Douro E Vouga, Rua Cândido Pinho, Santa Maria Da Feira
Portugal

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/pajo.pajo_58_22

Abstract

Objective: The objective of the study was to assess the glycemic control and cardiovascular risk (CV risk) change in diabetes mellitus type II (DM-II) patients undergoing uncomplicated bilateral cataract phacoemulsification surgery.
Design: Retrospective study.
Participants: We selected 28 patients who underwent uncomplicated bilateral cataract surgery at Centro Hospitalar de Entre o Douro e Vouga between January 2018 and December 2019.
Inclusion Criteria: We included patients submitted to bilateral cataract surgery without other known ophthalmological pathology. Furthermore, there were available records of their comorbidities, lipid profile, blood pressure, glycated hemoglobin (HbA1c), and body max index (BMI) prior to and in the 6 months following surgery.
Materials and Methods: We assessed our patient cohort for changes in HbA1c, lipid profile, BMI, and blood pressure before and after surgery. We further subdivided our patient cohort into two different groups: group 1 – no to mild visual impairment, ≤0.48 logarithm of the Minimum Angle of Resolution (LogMAR); Group 2 – moderate to severe visual impairment, >0.48 LogMAR, and assessed for the same variables at the mentioned time points. Comparisons were done using paired samples Student's t-test or Wilcoxon rank and repeated measures ANOVA with Tukey's post hoc tests, respectively.
Results: Following cataract surgery and subsequent improved visual acuity (VA), our patient cohort showed decreased HbA1c, lower arterial blood pressure, and decreased BMI, with an improved CV risk score within 6 months of cataract surgery. These improvements were more evident in the patients with worse baseline VA.
Conclusions: Phacoemulsification cataract surgery resulted in improved CV risk and glycemic control in DM-II patients.

Keywords: Cardiovascular-risk, cataracts, diabetes mellitus Type II

How to cite this article:
Matias MJ, Alves-Peixoto P, Rocha A, Chibante-Pedro J. Improved glycemic control and cardiovascular risk in patients with diabetes mellitus Type II following cataract phacoemulsification surgery. Pan Am J Ophthalmol 2023;5:7

How to cite this URL:
Matias MJ, Alves-Peixoto P, Rocha A, Chibante-Pedro J. Improved glycemic control and cardiovascular risk in patients with diabetes mellitus Type II following cataract phacoemulsification surgery. Pan Am J Ophthalmol [serial online] 2023 [cited 2023 Jun 3];5:7. Available from: https://www.thepajo.org/text.asp?2023/5/1/7/372590

Introduction

Over 94 million people are estimated to suffer from cataracts, a major cause of visual impairment and blindness worldwide.^[1] This is a significant public health problem and source of health-care expenditure, since impaired vision correlates with lower quality of life, increased difficulty in the performance of routine tasks, and greater social dependence.^[2],[3] Furthermore, impaired vision is associated with increased prevalence of other comorbidities, including depression,^[4] falls, and fractures.^[5] Of note, vision loss associates with a higher prevalence of underlying chronic diseases such as cardiovascular diseases (CVDs) and decreased life expectancy.^{[6],[7],[8],[9],[10],[11]}

There are many risk factors for the development of cataracts, chiefly increasing age, but also many CVDs, such as diabetes, hypertension, and dyslipidemia.^{[12],[13],[14],[15],[16]} DM-II, in particular, is associated with an over 2-fold increase in the risk of cataract development.^[17],[18] It has been suggested that this occurs due to multiple factors: the accumulation of polyols that leads to a hyperosmotic effect resulting in formation of lens opacities; the osmotic stress contributes to the swelling of the cortical lens fibers; the fluctuation of glucose levels leads to the production of reactive oxygen species and cause oxidative stress damage to lens fibers; the increased glucose levels in patients with DM-II leads to increased glycation of the lens proteins, further contributing to the development of cataracts.^{[19],[20],[21],[22]}

Cataract phacoemulsification surgery is one of the most common surgical procedures performed worldwide, highly effective in reducing visual impairment induced by cataract, while having a major positive impact in patients' daily activities and quality of life.^[23] While we have comprehensive knowledge regarding the influence of cardiovascular diseases and diabetes mellitus to the development of cataracts,^[24] we lack this understanding regarding the change in cardiovascular risk and glycemia control following surgery.

In this study, we aimed to assess the glycemia control and cardiovascular risk before and after cataract phacoemulsification surgery in patients with DM-II. With that in mind, we analyzed a cohort of patients submitted to bilateral cataract surgery for their visual acuity (VA), lipid profile, glycated hemoglobin (HbA1c), arterial blood pressure, and body max index (BMI) and calculated 10-year CV risk score before and after surgery.

Materials and Methods

Study patients, inclusion criteria, and data collection

This study adhered to the Code of Ethics of the World Medical Association (Declaration of Helsinki) for experiments involving humans and ethics approval was obtained from the Comissão de Ética para a Saúde at CHEDV. This was a retrospective study of 28 DM-II patients who underwent bilateral uncomplicated phacoemulsification surgery at CHEDV. In our study we included DM-II patients submitted to bilateral phacoemulsification cataract surgery with available clinical records of VA, peripheral blood levels of total cholesterol (TC), high density lipoproteins (HDL), low density lipoproteins (LDL), triglycerides (Tg), percentage of HbA1c, as well as systolic arterial blood pressure (SAP) and diastolic arterial blood pressure (DAP) before and 6 months following surgery. Patients with other known ophthalmological pathology (including glaucoma, macular degeneration, and diabetic retinopathy) were excluded from the study. The CV risk of each patient was calculated, before surgery and 6 months after surgery, using the risk prediction algorithm HeartScore® from the European Association of Preventive Cardiology,^[25] available online,^[26] and considering Portugal as a moderate risk country for CVDs.^[26] VA clinical information was converted to the logarithm of the Minimum Angle of Resolution (LogMAR) scale. Based on the WHO classification of visual impairment,^[27] we further subdivided our patient cohort into two groups of patients: group 1, no to mild visual impairment, logMAR ≤0.48 in the better eye before surgery; Group 2, moderate to severe visual impairment, logMAR >0.48 in the better eye before surgery.

Data analysis

Statistical analysis was performed using jamovi version 2.3.2 (the jamovi project, Sydney, Australia).^{[28],[29],[30],[31]} Variables were tested for their normal distribution using the ShapiroWilk test. To compare two different groups, if normality was present, we used parametric paired samples Student's t-test; if normality was not present, we used nonparametric paired samples Wilcoxon rank test. For the comparison of age between Group 1 and Group 2, we used nonparametric MannWhitney independent samples t-test. For the comparison of categorical variables between VA Groups 1 and 2, we used the Fisher's exact test of association. To compare variables between VA Groups 1 and 2, at the time points before and after surgery, we used ANOVA for repeated measures followed by Tukey's post hoc comparison tests. Differences were considered significant for P < 0.05 and represented as *P < 0.05; **P < 0.01; ***P < 0.001.

Results

Our cohort of DM-II 28 patients was submitted to bilateral cataract phacoemulsification between January 2018 and December 2019. All patients did not have any other known eye pathology. The demographic characteristics and comorbidities are summarized in [Table 1]. The mean age of our patient cohort was 74.3 ± 7.73 years, with 46.4% of patients being men and 53.6% women. Among the comorbidities of this cohort, other than DM-II and vascular disease (100% of the cohort), the most prevalent were hypertension (78.6% of patients), dyslipidemia (60.7% of patients), depression/anxiety syndrome (28.6%), osteoarticular pathology, and chronic lung disease (17.9%) [Table 1], which is compatible to what is observed in the Portuguese population,^[32] with most of these comorbidities, namely DM-II, hypertension and dyslipidemia, themselves constituting independent risk factors for the development of cataracts.^[14],[33]

Table 1: Demographic characteristics and comorbidities of study cohort

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Cataract phacoemulsification surgery resulted in an improvement of the median VA from 0.7071 ± 0.6040 logMAR to 0.0482 ± 0.0938 logMAR [Figure 1]a. Simultaneously, our patient cohort showed improved SAP, from mean values of 140.9 ± 15.36 mmHg to 132.9 ± 7.83 mmHg [Figure 1]f, decreased BMI, from a median of 29.72 ± 5.5682 kg/m to 29.02 ± 5.2846 kg/m2 [Figure 1]h, and decreased percentage of peripheral blood HbA1c, from 6.9% ±1.07% to 6.61% ±0.85% [Figure 1]i. No changes were observed in the lipid profile of our patient cohort, namely peripheral blood levels of TC, HDL, LDL, and Tg [Figure 1]b, [Figure 1]c, [Figure 1]d, [Figure 1]e nor in DAP [Figure 1]g. In the end, we used the risk prediction algorithm HeartScore® from the European Association of Preventive Cardiology available online^[26] to calculate the CV risk before and after surgery, inputting, gender, TC, SAP, TC, HDL, LDL, and current smoker status. This showed that following surgery, the CV risk score of our patient cohort decreased from a mean of 15.7% ±8.38% to 14.3% ±8.22% [Figure 1]j.

Figure 1: Following cataract phacoemulsification surgery, patients show improved VA, lipid profile, decreased systolic arterial blood pressure, HbA1c, BMI and CV risk score. VA LogMAR scores (a), TC (b), HDL (c), LDL (d) and Tg (e) peripheral blood levels (mg/dL), SAP (f) and DAP (g) (mmHg), BMI (kg/m²) (h), HbA1c percentage (%) (i), and CV risk score (%) before (pre) and after (post) surgery (j). Comparisons between time points were performed using the nonparametric paired samples Wilcoxon rank test (a, b, h and i) or parametric paired samples Student's t-test (c-g). Each graph represents the mean ± 95% confidence interval and the mean/median. VA: Visual acuity, HbA1c: Glycated hemoglobin, BMI: Body max index, CV: Cardiovascular, LogMAR: Logarithm of the Minimum Angle of Resolution, TC: Total cholesterol, HDL: High density lipoproteins, LDL: Low density lipoproteins, Tg: Triglycerides, SAP: Systolic arterial blood pressure

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Following this, we aimed to assess if patients with different baseline VA significantly differed in their CV risk and glycemic control improvement following surgery. For that, we divided our patient cohort in two different groups with different baseline VA, considering the WHO classification of visual impairment:^[27] group 1, with 18 patients, no to mild visual impairment, logMAR ≤0.48 in the better eye before surgery; Group 2, with 10 patients, moderate to severe visual impairment, logMAR >0.48 in the better eye before surgery. Of note, both the groups had comparable age and gender distributions, as well as comparable frequencies of comorbidities [Table 2].

Table 2: Comparison of study groups for age, gender, and comorbidities

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The patient cohort was subdivided in two groups according to their baseline VA: group 1, no to mild visual impairment, logMAR ≤0.48 in the better eye before surgery; group 2, moderate to severe visual impairment, logMAR >0.48 in the better eye before surgery. [Table 2] shows the comparisons between Group 1 and Group 2 for the different demographic characteristics and comorbidities. Age was compared using Student's independent-samples t-test, with the P value. All categorical variables between the two different groups were compared using the independent samples Fisher's exact test of association, with P the value.

Group 1 and 2 had significantly different baseline VA 0.4389 ± 0.1153 LogMAR and 1.1900 ± 0.1547 LogMAR, respectively. Following surgery both the groups showed remarkable improvement in VA to 0.0361 ± 0.0222 LogMAR and 0.0700 ± 0.0297 LogMAR, respectively [Figure 2]a. There was no significant improvement in the peripheral blood lipid profile of Group 1 and 2, despite trends of Tg decreasing following surgery in both the groups [Figure 2]b, [Figure 2]c, [Figure 2]d, [Figure 2]e. In contrast, SAP decreased following surgery, particularly in Group 2 of patients, from 146 ± 4.78 mmHg to 132 ± 2.51 mmHg, while this was more modest in group 1, from 138 ± 3.67 mmHg to 134 ± 1.93 mmHg [Figure 2]f. For DAP, we did not see significant improvements following surgery in neither of the two groups [Figure 2]g. As for BMI, both the groups showed comparable reduction trends following surgery, from 28.7 ± 1.88 kg/m² to 27.7 ± 1.77 kg/m² and from 30.3 ± 1.37 kg/m² to 29.7 ± 1.28 kg/m², respectively [Figure 2]h. Similarly, both Group 1 and Group 2 showed similar downward trends in the percentage of peripheral blood HbA1c following surgery, from 6.82% ±0.258% to 6.61% ±0.206% and from 7.04% ±0.346% to 6.63% ±0.277%, respectively [Figure 2]i. Overall, our patient cohort showed a reduced CV risk following surgery, particularly Group 2, the one with the worse VA at baseline, from 16.1% ±2.70% to 14.2% ±2.65%.

Figure 2: The group of patients with worse VA prior to cataract phacoemulsification surgery is the one showing the more impactful reduction in CV risk. VA LogMAR scores (a), TC (b), HDL (c), LDL (d) and Tg (e) peripheral blood levels (mg/dL), SAP (f) and DAP (g) (mmHg), BMI (kg/m²) (h), HbA1c percentage (%) (i), and CV risk score (%) before (pre) and after (post) surgery (j) in patients from Group 1 and Group 2. Comparisons between group 1 and group 2, before and after cataract phacoemulsification surgery, were performed using ANOVA for repeated measures followed by Tukey's post hoc analysis. Each graph represents the mean ± 95% confidence interval and the median. VA: Visual acuity, CV: Cardiovascular, LogMAR: Logarithm of the Minimum Angle of Resolution, HDL: High density lipoproteins, LDL: Low density lipoproteins, TC: Total cholesterol, Tg: Triglycerides, SAP: Systolic arterial blood pressure, HbA1c: Glycated hemoglobin

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Discussion

DM-II and dysregulated blood glucose levels contribute to the development of cataracts.^[17],[18] We hypothesized that following cataract phacoemulsification surgery, DM-II patients would show improved glycemic control and cardiovascular risk. This is because following cataract surgery, it is believed that patients show increased involvement in daily-life activities and overall are more active, possibly due to improved vision.^[23] Our results support this hypothesis, since following surgery there was an improvement in SAP, BMI, Hba1c and CV risk.

Outstandingly, these results were particularly evident in patients with worse baseline VA, since our cohort subgroup 2, with a baseline VA of over >0.48 LogMAR, displayed the most impactful reduction in SAP, BMI, HbA1c, and cardiovascular risk. Since both subgroups end having comparable VA following cataract surgery, we hypothesize that the higher the VA improvement, the more impactful is the CV risk reduction and the better peripheral blood glycemia is. These may occur due to increased physical activity, improved psychological well-being, higher integration in family and friends' activities, higher adherence to treatment regimens, among others.^[34]

Since CVDs are the leading cause of death globally, to which DM-II is a huge risk factor,^[35] and that the majority of CVDs and related deaths occur in adults older than 75 years,^[36] this study shows a new possible CV risk modifier. As cataract surgical becomes more and more effective in improving VA, with ever increasing levels of safety,^[37] our results suggest that the presence of cataracts and decreased VA should be readily addressed in patients with DM-II, with the intention of improving disease control and decrease the chances of DM-II related complications developing.

Acknowledgments

We thank all ophthalmology surgeons at Serviço de Oftalmologia do Centro Hospitalar de Entre o Douro e Vouga for performing the phacoemulsification cataract surgeries and the clinical follow-up of the patients involved in this study. We also thank the Clinical Information Managers who selected the patients to be involved in this study, obeying the inclusion criteria beforementioned.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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