Neutrophil to lymphocyte ratio in parkinson's disease: a systematic review and meta-analysis.
Level 3 - non-randomized controlled study
Systematic review and meta-analysis of observational studies
PubMed 37735638 · doi:10.1186/s12883-023-03380-7
What was done
Authors searched PubMed, Web of Science, and ProQuest from inception to June 4, 2023, for studies comparing the neutrophil-to-lymphocyte ratio (NLR) between patients with Parkinson's disease (PD) and healthy controls. Standardized mean differences (SMD) with 95% confidence intervals (CI) were calculated using a random-effects model, along with subgroup analyses by study design and ethnicity, and pooled sensitivity and specificity.
What was found
PD patients had significantly higher NLR values than healthy individuals (SMD = 0.81, 95% CI: 0.47 to 1.14, P < 0.001). - Subgroup by study design: Elevated in retrospective (SMD = 1.12, 95% CI: 0.58 to 1.66, P < 0.001) and prospective studies (SMD = 0.43, 95% CI: 0.18 to 0.68, P = 0.001). - Subgroup by ethnicity: Elevated in East Asian (SMD = 0.93, 95% CI: 0.22 to 1.63, P = 0.010) and Caucasian cohorts (SMD = 0.75, 95% CI: 0.40 to 1.10, P < 0.001). - Diagnostic performance: Pooled sensitivity was 0.67 (95% CI: 0.61 to 0.73) and pooled specificity was 0.66 (95% CI: 0.61 to 0.70).
Why it matters
This meta-analysis supports systemic inflammatory involvement in Parkinson's disease. However, with sensitivity and specificity around 66-67%, NLR has limited standalone diagnostic utility.
Limits
The abstract does not state the total number of included studies or participants. The underlying evidence is observational and susceptible to confounding, with prospective studies showing a substantially smaller effect size than retrospective designs.
Cited by
- supports Parkinson's disease patients have highly elevated neutrophil counts in blood.