Table Of ContentImpact of a Point-‐‑of-‐‑Care Rapid Influenza Test on Antibiotic Prescribing Patterns in
Southern Sri Lanka
by
L. Gayani Tillekeratne
Duke Global Health Institute
Date:_______________________
Approved:
___________________________
Christopher W. Woods, Supervisor
___________________________
Nathan M. Thielman
___________________________
Truls Ostbye
___________________________
Champica K. Bodinayake
___________________________
Megan E. Reller
Thesis submitted in partial fulfillment of
the requirements for the degree of
Master of Science in the Duke Global Health Institute in the Graduate School of Duke
University
2014
ABSTRACT
Impact of a Point-‐‑of-‐‑Care Rapid Influenza Test on Antibiotic Prescribing Patterns in
Southern Sri Lanka
by
L. Gayani Tillekeratne
Department of Global Health
Duke University
Date:_______________________
Approved:
___________________________
Christopher W. Woods, Supervisor
___________________________
Nathan M. Thielman
___________________________
Truls Ostbye
___________________________
Champica K. Bodinayake
___________________________
Megan E. Reller
An abstract of a thesis submitted in partial
fulfillment of the requirements for the degree
of Master of Science in the Duke Global Health Institute in the Graduate School of Duke
University
2014
Copyright by
L. Gayani Tillekeratne
2014
Abstract
Background: Acute febrile respiratory illnesses, including influenza, account for
a large proportion of ambulatory care visits worldwide. In the developed world, these
encounters commonly result in unwarranted antibiotic prescriptions; data from more
resource-‐‑limited settings are lacking. The purpose of this study was to describe the
epidemiology of influenza among outpatients in southern Sri Lanka and to determine if
access to rapid influenza test results was associated with decreased antibiotic
prescriptions.
Methods: In this pretest-‐‑ posttest study, consecutive patients presenting from
March 2013-‐‑ April 2014 to the Outpatient Department of the largest tertiary care hospital
in southern Sri Lanka were surveyed for influenza-‐‑like illness (ILI). Patients meeting
World Health Organization criteria for ILI-‐‑-‐‑ acute onset of fever ≥38.0°C and cough in
the prior 7 days—were enrolled. Consenting patients were administered a structured
questionnaire, physical examination, and nasal/nasopharyngeal sampling. Rapid
influenza A/B testing (Veritor System, Becton Dickinson) was performed on all patients,
but test results were only released to patients and clinicians during the second phase of
the study (December 2013-‐‑ April 2014).
Results: We enrolled 397 patients with ILI, with 217 (54.7%) adults ≥12 years and
188 (47.4%) females. A total of 179 (45.8%) tested positive for influenza by rapid testing,
iv
with April-‐‑ July 2013 and September-‐‑ November 2013 being the periods with the highest
proportion of ILI due to influenza. A total of 310 (78.1%) patients with ILI received a
prescription for an antibiotic from their outpatient provider. The proportion of patients
prescribed antibiotics decreased from 81.4% in the first phase to 66.3% in the second
phase (p=.005); among rapid influenza-‐‑positive patients, antibiotic prescriptions
decreased from 83.7% in the first phase to 56.3% in the second phase (p=.001). On
multivariable analysis, having a positive rapid influenza test available to clinicians was
associated with decreased antibiotic use (OR 0.20, 95% CI 0.05-‐‑ 0.82).
Conclusions: Influenza virus accounted for almost 50% of acute febrile
respiratory illness in this study, but most patients were prescribed antibiotics. Providing
rapid influenza test results to clinicians was associated with fewer antibiotic
prescriptions, but overall prescription of antibiotics remained high. In this developing
country setting, a multi-‐‑faceted approach that includes improved access to rapid
diagnostic tests may help decrease antibiotic use and combat antimicrobial resistance.
v
Contents
Abstract .......................................................................................................................................... iv
List of Tables ................................................................................................................................. ix
List of Figures ............................................................................................................................... xi
Acknowledgements .................................................................................................................... xii
1. Background ................................................................................................................................ 1
1.1 Global burden and seasonality of influenza ................................................................. 1
1.2 Epidemiology of influenza in Sri Lanka ........................................................................ 3
1.3 Influenza, antibiotic use, and the impact of rapid diagnostic testing ....................... 5
2. Objectives .................................................................................................................................. 8
3. Setting ......................................................................................................................................... 9
3.1 Background on Sri Lanka and its healthcare infrastructure ...................................... 9
3.2 Duke-‐‑Ruhuna Collaboration ......................................................................................... 10
4. Methods .................................................................................................................................... 12
4.1 Study setting .................................................................................................................... 12
4.2 Study procedures ............................................................................................................ 12
4.3 Sample processing .......................................................................................................... 13
4.4 Study design .................................................................................................................... 15
4.5 Analysis plan ................................................................................................................... 16
4.6 Ethical considerations .................................................................................................... 17
5. Results ...................................................................................................................................... 18
5.1. Description of study population ................................................................................. 22
vi
5.1.1 Sociodemographic characteristics ........................................................................... 22
5.1.2 Exposures and risk factors ....................................................................................... 26
5.1.3 Prior care ..................................................................................................................... 27
5.1.4 Clinical presentation ................................................................................................. 28
5.1.5 Rapid influenza test results ...................................................................................... 30
5.1.6 Clinical management ................................................................................................ 34
5.1.7 Impact on finances and productivity ...................................................................... 34
5.2 Comparison of first and second phases ...................................................................... 35
5.2.1 Sociodemographic characteristics, exposures, and impact on finances and
productivity ......................................................................................................................... 35
5.2.2 Clinical characteristics and physical exam findings ............................................. 36
5.2.3 Rapid influenza test results and clinical management ........................................ 37
5.3 Bivariable analysis of features associated with influenza ........................................ 38
5.3.1 Sociodemographic characteristics, exposures, and clinical symptoms ............. 38
5.3.2 Clinical management ................................................................................................ 39
5.4 Bivariable analysis of features associated with antibiotic prescriptions ................ 43
5.4.1 Sociodemographic characteristics, exposures, and clinical symptoms ............. 43
5.4.2 Clinical management ................................................................................................ 43
5.5 Multivariable analysis of features associated with influenza .................................. 48
5.6 Multivariable analysis of features associated with receipt of an antibiotic
prescription ............................................................................................................................ 49
6. Discussion ................................................................................................................................ 51
6.1 ILI and influenza patterns in southern Sri Lanka ...................................................... 51
vii
6.2 Clinical presentation of influenza ................................................................................ 55
6.3 ILI and antibiotic use ...................................................................................................... 56
7. Ongoing work .......................................................................................................................... 66
8. Conclusions ............................................................................................................................. 67
Appendix A ................................................................................................................................... 68
References ................................................................................................................................... 70
viii
List of Tables
Table 1: Sociodemographic characteristics of outpatients enrolled with ILI in southern
Sri Lanka from March 2013-‐‑ April 2014, listed for the entire study population as well as
for each phase of the study. ....................................................................................................... 25
Table 2: Exposures and risk factors for outpatients with ILI in southern Sri Lanka, March
2013-‐‑ April 2014, listed for the entire study population as well as for each phase of the
study. ............................................................................................................................................. 27
Table 3: Clinical symptoms, exam findings, and clinical diagnoses and treatment
received among outpatients with ILI in southern Sri Lanka, March 2013 to April 2014 .. 29
Table 4: Impact of illness on finances and productivity among outpatients with ILI in
southern Sri Lanka from March 2013-‐‑ April 2014, listed for the total study population as
well as for each phase of the study. .......................................................................................... 35
Table 5: Bivariable analysis of sociodemographic characteristics, exposures, and clinical
characteristics associated with rapid influenza positivity among outpatients with ILI in
southern Sri Lanka, March 2013-‐‑ April 2014. .......................................................................... 40
Table 6: Bivariable analysis of cost and productivity variables associated with rapid
influenza positivity among outpatients with ILI in southern Sri Lanka, March 2013-‐‑
April 2014. .................................................................................................................................... 42
Table 7: Bivariable analysis of clinical diagnoses and treatments associated with rapid
influenza positivity in outpatients with ILI in southern Sri Lanka, March 2013-‐‑ April
2014 ................................................................................................................................................ 42
Table 8: Bivariable analysis of sociodemographic characteristics and clinical features
associated with antibiotic prescriptions for outpatients with ILI in southern Sri Lanka,
March 2013-‐‑ April 2014. ............................................................................................................. 45
Table 9: Bivariable analysis of cost and productivity variables associated with antibiotic
prescriptions for outpatients with ILI in southern Sri Lanka, March 2013-‐‑ April 2014. ... 47
Table 10: Bivariable analysis of clinical diagnoses and treatments associated with
antibiotic prescriptions for outpatients with ILI in southern Sri Lanka, March 2013-‐‑ April
2014. ............................................................................................................................................... 47
ix
Table 11: Multivariable analysis of sociodemographic characteristics, exposures, clinical
symptoms, and exam findings associated with rapid influenza positivity among
outpatients with ILI in southern Sri Lanka, March 2013-‐‑ April 2014. ................................. 49
Table 12: Multivariable analysis of sociodemographic characteristics, exposures, clinical
symptoms, and exam findings associated with antibiotic prescriptions among
outpatients with ILI in southern Sri Lanka, March 2013-‐‑ April 2014. ................................. 50
x
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