Proteinuria clinically useful predictive marker for developing ocular motor cranial nerve palsy : Study

Knowing the relationship between proteinuria and oculomotor CNP will be important in mechanisms underlying CNP development and formulation of preventive strategies. Proteinuria, easily detectable by a simple urine dipstick test, has already been related to several systemic diseases but not with CNP. Therefore, the present nationwide population-based cohort study using the data of the National Health Insurance Service of Korea was conducted to examine this possible relationship.

In this research, the data spanned from the NSC database of Korea's NHIS from 2009 to 2018. An explicit temporal relationship between proteinuria and CNP development was adopted with a one-year time lag. The participants included those aged 20 or older with newly diagnosed proteinuria in 2009, while those with pre-existing conditions of CNP or with missing data and who are newly diagnosed with CNP, or who died within one year, were excluded. Proteinuria levels ranged from negative to trace or between 1+ to 4+. For the assessment of the association of proteinuria level with the risk of oculomotor CNP incidence, Cox proportional hazard regression analysis was conducted.

Key Findings

Out of the total cohort, 5,807 individuals (0.14%) were diagnosed with oculomotor CNP, while 4,047,205 served as the control group.

Proteinuria and CNP Risk: After adjusting for comorbidities, the hazard ratios (HRs) for developing oculomotor CNP were:

• 1+ proteinuria: HR 1.449 (95% CI 1.244–1.687)

• 2+ proteinuria: HR 2.081 (95% CI 1.707–2.538)

• 3+ proteinuria: HR 1.960 (95% CI 1.322–2.904)

• 4+ proteinuria: HR 3.011 (95% CI 1.507–6.014)Subgroup Analysis: The risk was higher in younger patients (under 40 years) with an HR of 1.547 (P=0.0242) and in those with diabetes mellitus (DM) with an HR of 1.763 (P=0.04).

A strong positive correlation was found between the incidence of oculomotor CNP and the presence and degree of proteinuria. In particular, the risk increased with higher levels of proteinuria, underlining that urine protein level is likely to be a predictive marker for CNP.This relationship comes out maximum in young age groups and patients with diabetes and might indicate that these groups need closer monitoring.

In this large cohort study, the importance of proteinuria as a predictor for oculomotor CNP is underscored. Routine clinical screening for proteinuria might help in the identification of individuals at higher risk for CNP and thus allow early interventions of preventive strategies. Further studies are needed to clarify the mechanisms underlying the proteinuria-CNP link and eventually to develop approaches aimed at a reduction of this risk.

Reference:

Lee, J., Han, K., Yoo, J., Park, K.-A., & Oh, S. Y. (2024). Proteinuria and risk of ocular motor cranial nerve palsy: a nationwide population-based study. Scientific Reports, 14(1), 1–10. https://doi.org/10.1038/s41598-024-62576-0