Introduction
Acute exacerbation (AE) is a severe complication of COPD (chronic obstructive pulmonary disease). However, biomarkers are lacking to predict the outcome of AE and the time till the next relapse. Platelets are involved in the inflammatory cascade during AECOPD, and increased platelet count (PLC) was linked with mortality after AE, but not to other disease outcomes.

Aim
We investigated if PLC or platelet-to-lymphocyte ratio (PLR) during an AE can predict negative outcomes and the time till the next relapse.

Methods
152 patients hospitalized with AE and treated with systemic corticosteroids were recruited and followed for 52 weeks or till the next moderate/severe AE. Using data on admission, patients were divided in tertiles, namely PLC-high (>297x109/L, n=50), PLC-medium (239-297x109/L, n=51) and PLC-low (<239x109/L, n=51). As well as PLR-high (>295, n=50), PLR-medium (147-295, n=51) and PLR-low (<147, n=51) accordingly. Clinical characteristics were were collected, analyzed and compared among the subgroups. ­­

Results
PLR and PLC showed no correlation to clinical characteristics, treatment failure or the time to the next AE (p>0.05). However, among patients with PLC in the reference range (n=138), the PLC-low group had higher rates of NIV use than the PLC-high group (22% vs. 4% p=0.04). In patients without systemic corticosteroid treatment before blood sampling (n=109), the PLR-high subgroup had higher use of NIV than the PLR-low group (24% vs. 7%, p=0.02).

Conclusion
PLC and PLR during a severe AECOPD are not markers to predict the time till next relapse but might predict the need of NIV during hospital stay.