Background:
Accurate estimates of the burden of antimicrobial resistance (AMR) are needed to establish the
magnitude of this global threat in terms of both health and cost, and to enable cost-effectiveness evaluations of
interventions aiming to tackle the problem. This review aimed to establish the alternative methodologies used in
estimating AMR burden in order to appraise the current evidence base.
Methods:
MEDLINE, EMBASE, Scopus, EconLit, PubMed and grey literature were searched. English
language studies evaluating the impact of AMR (from any microbe) on patient, payer/provider and economic
burden published between January 2013 and December 2015 were included. Independent screening of
title/abstracts followed by full texts was performed using pre-specified criteria. A study quality score (from zero
to one) was derived using Newcastle-Ottawa and Phillips checklists. Extracted study data were used to compare
study method and resulting burden estimate, according to perspective. Monetary costs were converted into 2013
USD.
Results:
Out of 5,187 unique retrievals, 214 studies were included. 187 studies estimated patient health, 75
studies estimated payer/provider and 11 studies estimated economic burden. 64% of included studies were
single centre. The majority of studies estimating patient or provider/payer burden used regression techniques.
48% of studies estimating mortality burden found a significant impact from resistance, excess healthcare system
costs ranged from non-significance to $1 billion per year, whilst economic burden ranged from $21,832 per case
to over $3 trillion in GDP loss. Median quality scores (interquartile range) for patient, payer/provider and
economic burden studies were 0.67 (0.56-0.67), 0.56 (0.46-0.67) and 0.53 (0.44-0.60) respectively.

Conclusions:
This study highlights what methodological assumptions and biases can occur dependent on
chosen outcome and perspective. Currently, there is considerable variability in burden estimates, which can lead
in-turn to inaccurate intervention evaluations and poor policy/investment decisions. Future research should
utilise the recommendations presented in this review.