Neutrophil-to-lymphocyte ratio predicts ischaemic stroke in Chinese T2DM patients

Neutrophil-to-lymphocyte ratio (NLR) is a significant predictor of new-onset ischaemic stroke in Chinese patients with type 2 diabetes mellitus (T2DM), the population-based Hong Kong Diabetes Study has shown.

The retrospective study included 85,351 patients with T2DM (mean age, 67.6 years; male, 48.8 percent) with complete blood count tests at baseline (between January and December 2009). The patients’ data were retrieved from the Clinical Data Analysis and Reporting System (CDARS) of public hospitals and clinics in Hong Kong. Follow-up was until December 2019 or death. [Endocrinol Diabetes Metab 2022;doi:10.1002/edm2.397]

During the follow-up period, new-onset ischaemic stroke occurred in 7,458 patients (8.74 percent), while new-onset atrial fibrillation (AF) occurred in 7,121 patients (8.87 percent). Patients who experienced new-onset stroke and mortality and those who experienced new-onset AF were found to have significantly higher NLR values compared with controls.

In univariable Cox regression analysis, increased NLR values in quartiles 2–4 were significantly associated with increased risk of new-onset ischaemic stroke compared with quartile 1 (quartile 2: hazard ratio [HR], 1.28; 95 percent confidence interval [CI], 1.20–1.37; p<0.001) (quartile 3: HR, 1.41; 95 percent CI, 1.32–1.51; p<0.001) (quartile 4: HR, 1.38; 95 percent CI, 1.29–1.47; p<0.001).

Increased NLR values in quartiles 2–4 were also associated with increased risk of AF in univariable Cox regression analysis (quartile 2: HR, 1.09; 95 percent CI, 1.02–1.17; p<0.015) (quartile 3: HR, 1.28; 95 percent CI, 1.20–1.37; p<0.001) (quartile 4: HR, 1.39; 95 percent CI, 1.31–1.49; p<0.001).

In multivariable analysis, NLR remained a significant predictor of ischaemic stroke risk for values in quartiles 2 and 3 (quartile 2: HR, 1.14; 95 percent CI, 1.05–1.22; p=0.001) (quartile 3: HR, 1.14; 95 percent CI, 1.06–1.23; p<0.001). However, significance was lost for NLR values in quartile 4 (HR, 1.08; 95 percent CI, 0.994–1.17; p=0.070).

After adjusting for cofounders, NLR was not found to be significantly predictive of AF (quartile 2: HR, 0.966; 95 percent CI, 0.874–1.07; p=0.499) (quartile 3: HR, 0.978; 95 percent CI, 0.884–1.08; p=0.661) (quartile 4: HR, 1.05; 95 percent CI, 0.935–1.16; p=0.462). “This suggested that NLR may also reflect the adjusted factors, including demographics and other past comorbidities, on top of directly indicating inflammation and its effect on AF,” the authors explained. “Indeed, NLR has been described to be associated with age, hypertension and heart failure – factors that were also adjusted in our regression model.” [Rom J Intern Med 2019;57:296-314; Hypertens Res 2019;42:1209-1214; J Clin Lab Anal 2015;29:437-443]

“NLR is a routine biomarker that reflects inflammatory states,” they noted. [Int Arch Med 2012;5:2]

In previous studies, NLR was shown to be associated with cardiovascular (CV) diseases, metabolic diseases and diabetic kidney disease, and was predictive of outcomes of various CV conditions. [Indian J Endocrinol Metab 2017;21:387-392; Am J Cardiol 2008;101:747-752; Pak J Med Sci 2017; 33:1366-1370; Hippokratia 2019;23:118-125; J Geriatr Cardiol 2019;16:671-675; Kardiol Pol 2018;76:107-118; Med Sci Monit Basic Res 2017;23:179-222; Anatol J Cardiol 2016;16:29-33; J Clin Med 2020;9:557; Medicine (Baltimore) 2018;97:e12432]

“Given the convenient and inexpensive nature of NLR testing, it could be readily applied in predicting the outcome of patients with AF and ischaemic stroke,” the authors suggested.