Study identifies key risk factors for thromboembolic events in patients with PNH

An analysis conducted on patients with paroxysmal nocturnal hemoglobinuria (PNH) who were not treated with C5 inhibitors has identified key risk factors for thromboembolic events (TE).

These factors include a history of TE, a high percentage of GPI-negative granulocytes (≥ 30%), and a lactate dehydrogenase (LDH) ratio ≥ 1.5 times the upper limit of normal (ULN) combined with ≥ 2 high disease activity (HDA) criteria.

The research, based on data from the International PNH Registry, included 2541 eligible patients. Among them, 57 with a history of at least 1 TE were closely examined and matched with 189 control patients without any TE history.

The findings revealed that patients with no previous TE history, who were concurrently under recent anticoagulation, exhibited a notably higher thrombotic risk with an odds ratio of 9.30 (95% CI: 1.20-72.27). Similarly, patients with a history of TE demonstrated an elevated risk, particularly when recent anticoagulation was involved. For those without recent anticoagulation, the odds ratio remained substantial at 5.33.

Patients with a GPI-negative granulocyte percentage of ≥ 30% but < 50% showed an odds ratio of 4.94, while those with ≥ 50% exhibited an odds ratio of 1.97. Patients with a lactate dehydrogenase ratio ≥ 1.5 times the upper limit of normal combined with ≥ 2 HDA criteria also exhibited an increased risk, with odds ratios ranging from 3.18 for 2-3 criteria, to 3.60 for ≥ 4 criteria.

Reference
Höchsmann B, Peffault de Latour R, Hill A, et al. Risk factors for thromboembolic events in patients with paroxysmal nocturnal hemoglobinuria (PNH): a nested case-control study in the International PNH Registry. Ann Hematol. 2023;doi: 10.1007/s00277-023-05402-3. Epub ahead of print. PMID: 37668788.