Literature Review
We systematically searched PubMed, Embase, and the Cochrane Library,
with two keywords vancomycin AND thrombocytopenia to start the search.
Clinical studies that evaluated thrombocytopenia caused by vancomycin,
without limitation to patients or controlled drugs. Papers written in
languages other English were excluded. Published reviews, case report,
conference abstracts and non-clinical studies were also excluded. The
reviewer (WGR) assessed publications for eligibility. Any paper with
uncertainty in regard to inclusion or exclusion was discussed between 3
authors (WGR, LXX and ZRS) until a consensus of opinion was reached.
Newcastle-Ottawa Scale (NOS) quality evaluation scale and JBI checklist
for analytical cross sectional studies were used to evaluate the quality
of included studies. 19,20 For each study, both the
process of data extraction and quality evaluation were performed by one
author (WGR) using predesigned tables, followed by the check of another
author (LXX). Any disagreement was resolved by discussion among all
authors (WGR, LXX and ZRS).
Overall, 600 articles were retrieved. After reviewing the titles,
abstracts and full texts, the reviewers agreed on a final selection of 6
studies for inclusion. The screening flow chart is presented in Figure
2, with the basic information of the six studies included shown in table
3. Of these, 5 studies were identified as retrospective cohort with a
controlled drugs as linezolid.13-17 One was a
cross-section study with a single-arm.18 The patients
were mainly adults with bacterial infection, and the duration treatment
(vancomycin or linezolid) was more than 7 days. Regarding quality
assessment, 5 cohort studies were identified as high quality (score 7-8)
based on NOS tool13-17, 1 cross section study as
medium quality (score 5) based on JBI tool.18 All
studies were therefore acceptable in this review.
We reviewed the
frequency,
severity and occurrence of bleeding events due to thrombocytopenia
caused by vancomycin or linezolid (Table 4 and Figure 2). Only one study
showed that the frequency of thrombocytopenia (defined as ≥ 30 %
decrease in platelets) caused by linezolid in patients was significantly
higher than that caused by vancomycin (OR = 3.38, 95 % CI:
1.87–6.08).17 Five studies showed that vancomycin and
linezolid had no significant difference in thrombocytopenia (either
defined as platelets<150 x 109/L or<100 x
109/L). As shown in Figure 3, the meta-analysis of the
two studies showed that vancomycin and linezolid had no significant
difference in thrombocytopenia (defined as platelets<150 x
109/L, RR=1.01,
95%CI=0.64-1.58).14-15 The cross-section study showed
that the incidence of vancomycin-induced thrombocytopenia (defined as
platelets<100 x 109/L) was 7.1
%.18 Although no life-threatening bleeding events was
reported to occur, vancomycin-induced thrombocytopenia can be as low as
less than half of the baseline platelets of patients. The above results
suggested that the incidence and severity of thrombocytopenia caused by
vancomycin should be paid attention.