[Small dose of low molecular weight heparin improves the prognosis of elderly patients with severe pneumonia: a Meta-analysis of 1 173 patients].

OBJECTIVE

To explore the effect of small dose of low molecular weight heparin on the prognosis of elderly patients with severe pneumonia using systematic evaluation method.

METHODS

Databases including Wanfang data, VIP, CNKI, SinoMed, PubMed, Embase and Cochrane Library were searched for randomized controlled trial (RCT) studies about the comparison of conventional therapy and low molecular weight heparin on prognosis of elderly patients with severe pneumonia from the time of database establishment to August 2019. The patients in conventional treatment group were treated by improving ventilation, anti-infection, eliminating phlegm, relieving asthma and maintaining homeostasis while those in low molecular weight heparin group were subcutaneously injected with low molecular weight heparin of 4 000 U, once a day for 7 days. The patients' main outcomes included the oxygenation index (PaO/FiO) after 7 days of treatment, duration of mechanical ventilation, mortality in hospital, and secondary outcomes included acute physiology and chronic health evaluation II (APACHE II) score and coagulation function after 7 days of treatment, the length of intensive care unit (ICU) stay, and incidence of bleeding. Data extraction and quality evaluation were conducted. The Meta-analysis of included studies that met the quality standards was performed using RevMan 5.3 software. Funnel diagram analysis was used to analyze the parameters with no less than 10 studies enrolled.

RESULTS

A total of 14 RCT studies were enrolled involving 1 173 elderly patients with severe pneumonia, among whom 590 received low molecular weight heparin while the other 583 received conventional therapy. All the included studies were well designed and of high quality. The results of Meta-analysis showed that compared with conventional therapy, small dose of low molecular weight heparin significantly elevated PaO/FiO after 7 days of treatment [mean difference (MD) = 19.25, 95% confidence interval (95%CI) was 16.88 to 21.61, P < 0.000 01], shortened the duration of mechanical ventilation (MD = -48.88, 95%CI was -67.42 to -30.33, P < 0.000 01), and decreased mortality in hospital [odds ratio (OR) = 0.40, 95%CI was 0.22 to 0.73, P = 0.003] and APACHE II score after 7 days of treatment (MD = -3.38, 95%CI was -3.94 to -2.83, P < 0.000 01), and shortened the length of ICU stay (MD = -4.51, 95%CI was -5.75 to -3.27, P < 0.000 01). There was no significant difference in the changes of coagulation parameters after 7 days of treatment or the incidence of bleeding between low molecular weight heparin group and conventional therapy group [7-day thrombin time (TT): MD = 0.57, 95%CI was -0.15 to 1.28, P = 0.12; 7-day prothrombin time (PT): MD = 0.32, 95%CI was -0.35 to 0.98, P = 0.35; 7-day fibrinogen (FIB): MD = -0.17, 95%CI was -0.45 to 0.10, P = 0.22; incidence of bleeding: OR = 0.86, 95%CI was 0.36 to 2.07, P = 0.74]. The funnel diagram showed that there was publication bias of included 10 studies about APACHE II score after 7 days of treatment.

CONCLUSIONS

Small dose of low molecular weight heparin can improve the prognosis of elderly patients with severe pneumonia and it has no obvious side-effect on coagulation function.