The main objective of this study is to investigate the non-inferiority of oral flucloxacillin alone compared with a combination of oral flucloxacillin and phenoxymethylpenicillin for the emergency department directed outpatient treatment of cellulitis, wound infections and abscesses, recently renamed by the Food and Drug Administration (FDA) as acute bacterial skin and skin structure infections (ABSSSIs). Half of the trial participants will receive flucloxacillin and placebo in combination, and the remaining half will be treated will flucloxacillin and phenoxymethylpenicillin. In a secondary objective the trial aims to measure adherence and persistence of trial patients with outpatient antibiotic therapy. In addition a within-trial evaluation of the cost per quality adjusted life year (QALY) gained from the use of oral flucloxacillin compared with combination therapy from the perspective of the health-care payer (direct costs) the patient and government. Finally the study will externally validate the Extremity Soft Tissue Infection-score, a Health Related Quality of Life (HRQL) questionnaire designed to quantify the impact of cellulitis, wound infections and abscesses on patient HRQL in clinical trials.
There is obvious clinical equipoise between the use of oral flucloxacillin alone or combined with phenoxymethylpenicillin for the emergency department treatment of cellulitis, wound infections and abscesses as evidenced by current disparate prescribing practice and hospital guidelines. Feasibility studies for the planned trial have shown that 45-50% of emergency department patients with these infections in Ireland are discharged on oral antibiotics which is consistent with findings in other jurisdictions. Despite the significant healthcare and economic costs associated with cellulitis, there is a paucity of scientific evidence concerning the appropriate antibiotic treatment for these conditions. Additionally, "less severe" infections tend to be over-treated and severe infections under-treated, indicating unjustifiable levels of antibiotic misuse, insufficient knowledge of therapeutics and a lack of evidence to risk-stratify patients with cellulitis to different treatments.The planned trial is therefore likely to be definitive due to the current clinical equipoise between the use of both penicillins for the emergency department outpatient treatment of this group of infections
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
414
One flucloxacillin capsule of 500mg strength taken four times daily for 7 days
One capsule of phenoxymethylpenicillin of 500 mg strength taken four times daily for 7 days
Over-encapsulation of phenoxymethylpenicillin will be performed by the manufacturer of the investigational medicinal products such that placebo and active phenoxymethylpenicillin are identical in size, shape, colour and smell, and are packaged in identical bottles
Department of Emergency Medicine, Connolly Hospital,
Blanchardstown, Dublin, Ireland
Department of Emergency Medicine, Mater Misericordiae University Hospital
Dublin, Dublin, Ireland
Beaumont Hospital,
Dublin, Dublin, Ireland
Department of Emergency Medicine, Mercy University Cork
Cork, Greenville Place, Ireland
Department of Emergency Medicine, Cork University Hospital
Cork, Wilton, Ireland
Investigator-determined clinical response
A trained member of the study team will determine clinical cure at the test of cure visit. This is a clinically-determined response to treatment based on the judgment of the trained member of the study team. Clinical cure will be defined as no treatment failure at any previous visit, and resolution or minimal presence of the erythema, swelling, tenderness, or induration from the baseline assessment, based on the study investigators clinical assessment
Time frame: Test Of Cure visit (Day 14-21 post randomization)
Early Clinical Response (ECR)
Early clinical response is defined as greater than or equal to a 20% reduction in the lesion surface area from that which was measured at enrolment.
Time frame: Day 2-3 post randomization
Clinical Treatment Failure
Any patient outcome designated as a clinical treatment failure at any time before and including the test of cure visit, will be categorized as a treatment failure. This commences with the early clinical response visit and includes serial changes in the surface area of the cellulitis lesion (erythema, oedema, tenderness and induration), clinical assessment of progress and health related quality of life measurements.
Time frame: Up to 21 days post randomization
Adherence to Medication
Medication adherence will be measured by counting the number of unused study medication at the end of treatment visit
Time frame: End of Treatment (EOT) visit Day 8-10 post randomization
Adherence to medication using an electronic medication event monitoring system (MEMS®)
A specific sub-study will be performed measuring adherence and persistence to antibiotic treatment using a MEMS® cap. The cap will be fitted to the dispensed medication bottle. MEMS® caps will be returned with the clinical trials supplies on the follow up visits.medication at the end of treatment visit
Time frame: Day 2-3 and day 8-10 post randomization and initiation of therapy
Measurement of Health Related Quality of Life
The EuroQol (EQ-5D-5L) will be used to obtain patient reports of health related quality of life and used in the estimation of quality adjusted life years.
Time frame: Day 2-3 post-randomization, Day 8-10 post randomization, Day 14 -21 post randomization
Validation of the Extremity Soft Tissue Infections (ESTI)- score
The ESTI will be used to obtain patient reports of health related quality of life and will be mapped on to EQ-5D-5L levels, to assess the accuracy of ESTI for use in cost-effectiveness studies
Time frame: Day 2-3 post-randomization, Day 8-10 post randomization, Day 14 -21 post randomization
Cost-effectiveness analysis
Analysis will consist of a within-trial evaluation of the cost QALY for oral flucloxacillin compared with oral flucloxacillin and phenoxymethylpenicillin over a one month time horizon from the perspective of the healthcare payer, the patient and the government. The CE analysis will use resource use data, where costs will be assigned to derive cost and will also use the QALY derived from the EQ5D-5L, to give overall cost per QALY.
Time frame: Day 14 - 21 post randomization
Measurement of Health Resource Use
A health economics resource utilization tool is being constructed to collect data on resource use, e.g. direct costs- hospital visits, primary care visits, and indirect costs such as transport and lost work productivity.
Time frame: Day 2-3 post-randomization, Day 8-10 post randomization, Day 14 -21 post randomization
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