IL-8 predicts early mortality in patients with acute hypercapnic respiratory failure treated with noninvasive positive pressure ventilation

This was a follow-up to an earlier study by this group, showing that IL-8 and GDF-15 were significant predictive risk markers for mortality in patients with acute dyspnea (Wiklund et al, 2016). Here they looked at patients with acute hypercapnic respiratory failure (AHRF). AHRF patients who don’t respond to standard medical treatment can be given noninvasive positive pressure ventilation (NPPV – pressured oxygen delivered via a face mask). However, this treatment is expensive, time-demanding and may not be tolerated by all patients, creating a need for relaible predictive markers for those who will or won’t respond to the treatment. Based on their previous dyspnea study and the premise that many forms of chronic respiratory disease may have an underlying low-grade systemic inflammation , they looked for any associations between IL-8/GDF-15 levels and clinical outcome In a prospective study of 46 AHRF patients who were treated with NPPV. The clinical endpoint used was death within 28 days after admission to the ER, which was the case for 13/46 patients (28%). Using two adjusted Cox hazard score models (one adjusting for age & gender and the other for age, gender and C-reactive protein levels), they saw that pre-treatment (at admission) both IL-8 and GDF-15 were significantly associated with 28-day mortality. When the highest IL-8 tertiles were entered into the two models, these patients showed a 10-fold and 13-fold increase respectively in risk for 28-day death, compared to the lowest tertile. Tertile analysis of GDF-15 showed only a modest 2.5-fold risk increase, in model 2 only, and when anaylzed as an independent risk factor, they concluded that GDF-15 is likely to be dependent on IL-8 levels. The authors concluded that IL-8 is a promising biomarker for 28-day mortality in AHRF patients treated by NPPV and could potentially be useful in stratifying patients for the choice of treatment used. While this limited study needs much more verification, they speculate a scenario where a high value of IL-8 at admission might prompt thephysician to select a more invasive treatment such as intubation.