Stroke continues to be a major public health problem globally. Stroke is frequent, recurring and more frequently disabling than being fatal. Although some risk factors and determinants of stroke such as age, gender, race, ethnicity, and heredity are non-modifiable, there are many modifiable risk factors. Controlling the modifiable factors such as lipid levels and serum uric acid levels may reduce the disease burden. [27]
In our study, fifty patients of ischemic stroke were included out of which 27(54.0%) were males and 23 (46.0%) were females. Similarly, fifty age and sex-matched healthy controls were also included. Mean age of the cases was 60.46±12.30 years ranging from 29 to 86 years whereas mean age of the controls was 60.21±12.12 years ranging from 29 to 81 years. Most of the cases in our study were in the age-group of 56-70 years (38.0%) followed by the age-group of 41-55 years (36.0%). Females cases have significantly higher mean age compared to males(p=0.02). Right sided Hemiparesis was found in 50% of the cases and remaining 50% were having left sided Hemiparesis.
A similar study by Mehrpour et al. [28] from Iran was done in 55 patients with acute ischaemic stroke of which, 30(63.6%) were males and rest 25(36.4%) were females. The mean age of the patients was 67.1±14.3 years somewhat higher than mean age of our cases. In a case control study by Dudhatra et al. [29], the mean age of the cases was 60.56±13.53 years and of control was 57.56±13.06 years and slight male preponderance was observed in both cases and controls similar to our findings. In the case control study by Bhadra et al. [30] conducted among 50 males with acute stroke and 50 age-matched healthy controls at PGIMS, Rohtak, Haryana, North India the mean age of the cases and controls were 59.28±12.31 and 59.88 ±12.06 years respectively similar to mean age of our study participants. In another case control study to assess role of serum uric acid in ischemic stroke by Khalil et al. [31] from Bangladesh, a total of 338 participants were recruited, of which 169 were cases and 169 were controls. Around 60 percent respondents of both case and control groups were males similar to our study population. In the study by Biyani VV et al. [32], 100 patients of first ever lifetime acute ischemic stroke were studied among which 68(68.0%) were males and 32(32.0%) females showing male preponderance. In a recent study by Arora et al. [33] from South India to assess serum uric acid levels and serum lipid levels in patients with ischemic cerebro-vascular accidents, a total of 60 patients were included out of which 43 (71.7%) were males and 17 (28.3%) were females and the mean age of the patients was 63.2 ±14.8 years similar to our case population.
In our study, the mean serum uric acid level of the cases was 6.49±-2.36 mg/dL whereas mean serum uric acid level of the controls was 5.59±0.98 mg/dL, the difference being statistically significant(p=0.01). Similarly, 22(44.0%) out of the 50 cases were hyperuricemic whereas only 8(16.0%) out of the 50 controls were hyperuricemic, this difference in prevalence being statistically significant too(p=0.002). With respect to correlation of serum uric acid levels with clinical and other laboratory parameters, age(r=0.279), Blood urea levels(r=0.608) and Serum creatinine levels(r=0.482) were found to be have significant positive correlation with serum uric acid.
In the study by Mehrpour et al. [28], the mean serum uric acid level of the patients was 5.94±1.70 mg/dL and 47.3% of the patients were hyperuricemic in line with our study findings. In the study by Dudhtara et al. [29], the mean blood uric acid level of cases was 4.98±1.45 mg/dL and that of controls was 4.36±1.45 mg/dl, the difference being statistically significant (p=0.035). Similarly, in the study by Bhadra et al. [30] the mean blood uric acid level of cases (5.68±1.94 mg/dL) was significantly higher than mean serum uric acid level of controls (3.72±0.96 mg/dL). In the study by Khalil et al. [31], the mean blood uric acid level of cases was 6.03±1.84 mg/dL and that of controls was 4.34±1.60 mg/dL, the difference being statistically highly significant(p=0.000) similar to our findings.
In the study by Biyani VV et al. [32], 49% of the patients of acute ischemic stroke had serum uric acid levels more than 8mg/dL similar to our finding of 44% patients having hyperuricemia. Similar results were also observed in the studies by Millinois et al. [34] and Patil et al. [35]. However, in the study by Arora et al. [33], mean serum uric acid levels of the patients was 5.5 ± 1.7 mg/dL, and 18 patients (30%) were hyperuricemic, both parameters somewhat lower than that found in our study.
In our study, dyslipidaemia was found in 40 (80.0%) cases and only 10(20%) controls(p<0.0001). A statistically significant inverse correlation(p=0.04) of serum uric acid levels with HDL-C was found in the case group. With regard to association of hyperuricemia with deranged lipid parameters, Increased TG levels were seen in 8(16.0%) cases compared to 2(0.0%) controls, (p=0.04). Similarly, Increased LDL-C levels were found in 3(6.0%) cases compared to 0(0.0%) (p=0.001). Finally, Increased VLDL-C levels were observed in 17(38.0%) cases compared to 4(8.0%) among controls (p<0.0001).
In the study by Mehrpour et al. [28] Hyperuricemia was found to be associated with increase in Triglycerides and LDL-C levels. Bhadra J et al. [29] found statistically significant positive correlation of serum uric acid levels with serum TG and VLDL-C levels and an inverse correlation with HDL-C, both among cases and controls. Khalil et al. [31] found no significant difference in serum uric acid levels with or without dyslipidaemia among the ischemic stroke patients. The study by Arora et al. [33] found dyslipidaemia to be seen among 81% of the patients with ischemic stroke similar to our findings. The correlation between serum uric acid levels of the patients and serum TC, TG, LDL and VLDL levels and HDL was found to be statistically non-significant in contrast to our finding of statistically significant inverse correlation between serum uric acid and HDL levels. In the study by Baluch U et al. [36], only 19% patients had dyslipidaemia, 18% had low HDL levels while High LDL, Total Cholesterol and Triglyceride levels were observed in 26%, 24% and 32% respectively. Albucher J.F. et al. [37] concluded in their study that low HDL cholesterol was the only serum lipid index to be associated with increased risk of stroke whereas Samah D et al. [38] found a significant positive correlation of serum uric acid levels with serum TC, TG, LDL, and negative correlation with serum HDL levels, also observed in our study.
Strengths & Limitations
This study was based on data collected from a department of a single tertiary care teaching Institute in Haryana, North India making it less representative for the entire population of the region or the country. Besides, population recruited in the control group was also taken from hospital OPD patients that might lead to selection bias. Although cases of this study were directly supervised for overnight fasting before collecting blood samples, supervision of the controls was not possible as they were taken from the out-patient department. Some other variables known to influence SUA level such as body mass index (BMI) and metabolic disorders were not addressed in the study. However, despite these limitations, this study provides a unique perspective since it has analyzed the role of SUA in acute ischemic stroke while considering some well-established cardiovascular risk factors.