Association between Serum Uric Acid Levels and Primary Open-angle Glaucoma: A Cross-sectional Study

Abstract

Introduction: There is an intricate association between serum Uric Acid (UA) levels and Primary Open Angle Glaucoma (POAG). UA levels in the blood are known to be a good indicator of antioxidant function, and a decrease in UA plays a key role in the pathogenesis of POAG. However, the association of serum UA and Uric Acid Creatinine Ratio (UACR) in POAG cases in the Indian population remains unexplored. Aim: To investigate the association of serum UA levels and serum UACR with POAG. Materials and Methods: This cross-sectional study was conducted among patients who attended the Outpatient Department (OPD) of Opthalmology at Maharajah’s Institute of Medical Sciences, Vizianagaram, Andhra Pradesh, India. The duration of the study was one year and six months, from January 15, 2021 to July 15, 2022. The study included 200 recently diagnosed patients with POAG, who were divided into three groups based on Intraocular Pressure (IOP): Group 1 (mild) with an IOP of 21-30 mmHg, group 2 (moderate) with an IOP of 31-50 mmHg, and group 3 (severe) with an IOP greater than 51 mmHg. Age and gender-matched 199 healthy subjects were included as the control group. Blood samples were collected from the study subjects after obtaining informed consent and were tested for serum UA (using the modified Trinder method) and serum creatinine (using Jaffe’s method) in a semiautomatic analyser (Erba chem 7). The data were analysed using Statistical Package for Social Sciences (SPSS) version 21.0 software and MS Excel 2007. Results: The mean age of the study participants of all three groups was found to be 51.19±5.06 years with 46.7% male and 53.3% female subjects. The serum UA levels were 5.55±0.74 mg/dL in the mild POAG group, 4.1±0.5 mg/dL in the moderate POAG group, and 2.67±0.6 mg/dL in the severe POAG group (p-value <0.001). The present study also found that among the three study groups of POAG, UA levels were the lowest in the severe POAG group, followed by the moderate POAG group, and then the mild POAG group. This pattern was observed in both the males and females population. Conclusion: The present study found that serum UA levels were decreased in POAG patients compared to the normal healthy control group. Furthermore, the study revealed a significant negative association between serum UA levels and serum UACR levels with the severity of POAG.