A systematic review of the efficacy of direct hemoperfusion with a polymyxin B–immobilized fibre column to treat rapidly progressive interstitial pneumonia

OBJECTIVES: Rapidly progressive interstitial pneumonia is a fatal disease with no established therapeutic options. The aim of this systematic review is to clarify the efficacy of interstitial pneumonia treatment utilizing direct hemoperfusion with a polymyxin B–immobilized fibre column. METHODS: All patients with adult-onset rapidly progressive interstitial pneumonia including acute exacerbation of underlying chronic interstitial pneumonia were eligible. Primary studies of any design, which compared outcomes of direct hemoperfusion with a polymyxin B–immobilized fibre column treatment such as oxygenation and all-cause mortality with those of conventional therapy, were included. Electronic databases such as Medline and EMBASE were searched through October 7, 2018, and ICHUSHI, the largest database for medical articles in Japan, was also searched. Two reviewers independently extracted the relevant data and assessed the risk of bias in individual studies. The results were reported qualitatively due to substantial heterogeneity between studies. RESULTS: Out of 775 records retrieved, 10 reports were eligible and 8 of them were included for further analysis. They were all retrospective studies including a total of 327 patients and contained some risk of bias. There was variation in the administration method of direct hemoperfusion with a polymyxin B–immobilized fibre column treatment such as the timing, frequency, duration and interval. Multivariate analyses of only two studies with historical controls demonstrated beneficial effects of direct hemoperfusion with a polymyxin B–immobilized fibre column treatment over conventional therapy with all-cause mortality hazard ratios of 0.345 (95% confidence interval: 0.127–0.936) and 0.505 (95% confidence interval: 0.270–0.904), respectively. A significant difference of an improvement in the ratio of partial arterial oxygen pressure to the fraction of inspired oxygen in-between two treatment groups was also reported in two studies utilizing historical controls with mean differences of 56.8 and 57.5 mmHg, respectively. CONCLUSIONS: There is currently insufficient data to support the use of direct hemoperfusion with a polymyxin B–immobilized fibre column treatment for rapidly progressive interstitial pneumonia. It should be instituted for research purposes only until new evidence is available.