Trial Outcomes & Findings for High-dose vs. Standard-dose Cephalexin for Cellulitis (NCT NCT04471246)

NCT ID: NCT04471246

Last Updated: 2025-01-17

Results Overview

% of patients recruited into the trial

• Recruitment status: COMPLETED
• Study phase: PHASE4
• Target enrollment: 69 participants
• Primary outcome timeframe: 6 months
• Results posted on: 2025-01-17

Participant Flow

Three randomized patients were excluded due to an alternat diagnosis, thus 66 moved forward for analysis (33 in each arm)

Participant milestones

Measure	High Dose Cephalexin The intervention is high-dose cephalexin (1000mg PO QID) for seven days Cephalexin: 1000 mg PO QID for 7 days	Standard Dose Cephalexin The comparator is standard-dose cephalexin (500mg PO QID) plus oral placebo for seven days Cephalexin: 500 mg PO QID plus oral placebo for 7 days
Overall Study STARTED	33	33
Overall Study COMPLETED	31	31
Overall Study NOT COMPLETED	2	2

Reasons for withdrawal

Measure	High Dose Cephalexin The intervention is high-dose cephalexin (1000mg PO QID) for seven days Cephalexin: 1000 mg PO QID for 7 days	Standard Dose Cephalexin The comparator is standard-dose cephalexin (500mg PO QID) plus oral placebo for seven days Cephalexin: 500 mg PO QID plus oral placebo for 7 days
Overall Study Lost to Follow-up	2	2

Baseline Characteristics

Race and Ethnicity were not collected from any participant.

Baseline characteristics by cohort

Measure	High Dose Cephalexin n=33 Participants The intervention is high-dose cephalexin (1000mg PO QID) for seven days Cephalexin: 1000 mg PO QID for 7 days	Standard Dose Cephalexin n=33 Participants The comparator is standard-dose cephalexin (500mg PO QID) plus oral placebo for seven days Cephalexin: 500 mg PO QID plus oral placebo for 7 days	Total n=66 Participants Total of all reporting groups
Age, Categorical <=18 years	1 Participants n=33 Participants	1 Participants n=33 Participants	2 Participants n=66 Participants
Age, Categorical Between 18 and 65 years	19 Participants n=33 Participants	22 Participants n=33 Participants	41 Participants n=66 Participants
Age, Categorical >=65 years	13 Participants n=33 Participants	10 Participants n=33 Participants	23 Participants n=66 Participants
Age, Continuous	56 years n=33 Participants	57 years n=33 Participants	56 years n=66 Participants
Sex: Female, Male Female	13 Participants n=33 Participants	13 Participants n=33 Participants	26 Participants n=66 Participants
Sex: Female, Male Male	20 Participants n=33 Participants	20 Participants n=33 Participants	40 Participants n=66 Participants
Race and Ethnicity Not Collected	—	—	0 Participants Race and Ethnicity were not collected from any participant.
Region of Enrollment Canada	33 participants n=33 Participants	33 participants n=33 Participants	66 participants n=66 Participants
BMI	30.4 kg/m2 n=33 Participants	27.9 kg/m2 n=33 Participants	29.1 kg/m2 n=66 Participants
Height	1.72 metres n=33 Participants	1.67 metres n=33 Participants	1.7 metres n=66 Participants
Weight	90 kg n=33 Participants	80 kg n=33 Participants	84.5 kg n=66 Participants

PRIMARY outcome

Timeframe: 6 months

Population: Number of patients within the 6 months of the trial that were determined to be eligible of the trial. Of 134, 69 were successfully approached and recruited in the study.

% of patients recruited into the trial

Outcome measures

Measure	Patients Identified as Eligible for the Trial n=134 Participants Total number of participants deemed eligible for the study	Standard Dose Cephalexin The comparator is standard-dose cephalexin (500mg PO QID) plus oral placebo for seven days Cephalexin: 500 mg PO QID plus oral placebo for 7 days
Patient Recruitment Rate	51.5 percentage of eligible patients	—

PRIMARY outcome

Timeframe: Each patient was assessed for oral antibiotic treatment failure at the day 3 and day 7 follow-ups

Population: Of 66 patients enrolled and confirmed to have cellulitis by the Principal Investigator, 62 were assessed for treatment failure. Four were lost to follow-up and therefore could not be assessed for treatment failure.

% of patients with oral antibiotic treatment failure

Oral antibiotic treatment failure, defined as a change in antibiotic (change in class of oral antibiotic or step up to intravenous therapy) within 7 days due to worsening infection, which is defined as:

1. New fever (temperature ≥ 38.0°C) or persistent fever at Day 3 follow up; or

2. Increasing area of erythema ≥20% from baseline; or

3. Increasing pain ≥2 points from baseline (numeric rating scale)

Outcome measures

Measure	Patients Identified as Eligible for the Trial n=31 Participants Total number of participants deemed eligible for the study	Standard Dose Cephalexin n=31 Participants The comparator is standard-dose cephalexin (500mg PO QID) plus oral placebo for seven days Cephalexin: 500 mg PO QID plus oral placebo for 7 days
Oral Antibiotic Treatment Failure	3.2 percentage of enrolled in each arm Interval 0.6 to 16.2	12.9 percentage of enrolled in each arm Interval 5.1 to 28.9

SECONDARY outcome

Timeframe: 6 months

% of eligible patients that were identified as being eligible but missed (staff was unable to approach to recruit in trial)

Outcome measures

Measure	Patients Identified as Eligible for the Trial n=134 Participants Total number of participants deemed eligible for the study	Standard Dose Cephalexin The comparator is standard-dose cephalexin (500mg PO QID) plus oral placebo for seven days Cephalexin: 500 mg PO QID plus oral placebo for 7 days
Ability to Approach Eligible Patients	14.2 percentage of eligible patients	—

SECONDARY outcome

Timeframe: Patient were asked which dose of cephalexin they believe they received during the day 7 follow-up

The percentage of patients that correctly guessed their treatment allocation.

To assess how well blinded the patients were to the medication they received, each was asked during the day 7 follow-up, after having finished their medication, to indicate which treatment they believe they received (500mg of 1000mg of cephalexin). Once unblinded to the allocation (after enrollment and follow-up complete), it was possible to determine which patients correctly guess the dose of medication they received.

Outcome measures

Measure	Patients Identified as Eligible for the Trial n=33 Participants Total number of participants deemed eligible for the study	Standard Dose Cephalexin n=33 Participants The comparator is standard-dose cephalexin (500mg PO QID) plus oral placebo for seven days Cephalexin: 500 mg PO QID plus oral placebo for 7 days
Assessment of Blinding	33.3 percentage of enrolled per arm	60.1 percentage of enrolled per arm

SECONDARY outcome

Timeframe: 7 days

% of patients that are adherent to allocated treatment for 7 days

Outcome measures

Measure	Patients Identified as Eligible for the Trial n=33 Participants Total number of participants deemed eligible for the study	Standard Dose Cephalexin n=33 Participants The comparator is standard-dose cephalexin (500mg PO QID) plus oral placebo for seven days Cephalexin: 500 mg PO QID plus oral placebo for 7 days
Protocol Adherence	75.8 percentage of enrolled and analyzed	75.8 percentage of enrolled and analyzed

SECONDARY outcome

Timeframe: Determined at final follow-up (day 14) if lost to follow-up

% of patients lost to follow-up at 14 days

Patients were lost to follow-up if they did not attend any follow-up visit at days 3, 7 and 14

Outcome measures

Measure	Patients Identified as Eligible for the Trial n=33 Participants Total number of participants deemed eligible for the study	Standard Dose Cephalexin n=33 Participants The comparator is standard-dose cephalexin (500mg PO QID) plus oral placebo for seven days Cephalexin: 500 mg PO QID plus oral placebo for 7 days
Loss to Follow-up	6.1 percentage of enrolled per arm	6.1 percentage of enrolled per arm

SECONDARY outcome

Timeframe: Assessed for clinical cure at day 7and day 14 follow-up

Population: Of the 66 enrolled and confirmed to have cellulitis, 4 were lost to follow-up. The remaining 62 were analyzed for clinical cure at days 7 and 14.

% of patients with clinical cure (no erythema, pain and fever) at days 7 and 14

Outcome measures

Measure	Patients Identified as Eligible for the Trial n=31 Participants Total number of participants deemed eligible for the study	Standard Dose Cephalexin n=31 Participants The comparator is standard-dose cephalexin (500mg PO QID) plus oral placebo for seven days Cephalexin: 500 mg PO QID plus oral placebo for 7 days
Clinical Cure Clinical cure at day 14	45.2 percentage of enrolled in each arm Interval 29.2 to 62.2	38.7 percentage of enrolled in each arm Interval 23.7 to 56.2
Clinical Cure Clinical cure at day 7	16.1 percentage of enrolled in each arm Interval 7.1 to 32.6	6.5 percentage of enrolled in each arm Interval 1.8 to 20.7

SECONDARY outcome

Timeframe: 14 days

Population: Of the 66 enrolled and confirmed to have cellulitis, 4 were lost to follow-up. The remaining 62 were assessed for adverse events.

% of patients with adverse events (e.g. vomiting, diarrhea, rash) at 14-days measured via telephone follow-up

Outcome measures

Measure	Patients Identified as Eligible for the Trial n=31 Participants Total number of participants deemed eligible for the study	Standard Dose Cephalexin n=31 Participants The comparator is standard-dose cephalexin (500mg PO QID) plus oral placebo for seven days Cephalexin: 500 mg PO QID plus oral placebo for 7 days
Adverse Events Diarrhea	16.1 percentage of enrolled in each arm Interval 7.1 to 32.6	6.5 percentage of enrolled in each arm Interval 1.8 to 20.7
Adverse Events Nausea or vomiting	9.7 percentage of enrolled in each arm Interval 3.4 to 24.9	3.2 percentage of enrolled in each arm Interval 0.6 to 16.2
Adverse Events Abdominal pain	3.2 percentage of enrolled in each arm Interval 0.6 to 16.2	0 percentage of enrolled in each arm Interval 0.0 to 11.0
Adverse Events Rash	3.2 percentage of enrolled in each arm Interval 0.6 to 16.2	6.5 percentage of enrolled in each arm Interval 1.8 to 20.7
Adverse Events Other	6.5 percentage of enrolled in each arm Interval 1.8 to 20.7	9.7 percentage of enrolled in each arm Interval 3.4 to 24.9
Adverse Events No adverse events to report	61.3 percentage of enrolled in each arm Interval 43.8 to 76.3	74.2 percentage of enrolled in each arm Interval 56.8 to 86.3

SECONDARY outcome

Timeframe: 14 days

Population: Of the 66 enrolled and confirmed to have cellulitis, 4 were lost to follow-up. The remaining 62 were assessed for unplanned ED visit or hospitalizations at the day 14 telephone follow-up

% of patients with unplanned i) return ED visits; and ii) hospitalization, measured via 14-day telephone follow-up

Outcome measures

Measure	Patients Identified as Eligible for the Trial n=31 Participants Total number of participants deemed eligible for the study	Standard Dose Cephalexin n=31 Participants The comparator is standard-dose cephalexin (500mg PO QID) plus oral placebo for seven days Cephalexin: 500 mg PO QID plus oral placebo for 7 days
Unplanned ED Visits or Hospitalization Unplanned visit to family doctor within 14 days	6.5 percentage of enrolled in each arm Interval 1.8 to 20.7	6.5 percentage of enrolled in each arm Interval 1.8 to 20.7
Unplanned ED Visits or Hospitalization Unplanned return to ED within 14 days	22.6 percentage of enrolled in each arm Interval 11.4 to 39.8	16.1 percentage of enrolled in each arm Interval 7.1 to 32.6
Unplanned ED Visits or Hospitalization Unplanned hospitalization within 14 days	0 percentage of enrolled in each arm Interval 0.0 to 11.0	0 percentage of enrolled in each arm Interval 0.0 to 11.0

Adverse Events

High Dose Cephalexin

Serious events: 0 serious events

Other events: 12 other events

Deaths: 0 deaths

Standard Dose Cephalexin

Serious events: 0 serious events

Other events: 8 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Measure	High Dose Cephalexin n=31 participants at risk The intervention is high-dose cephalexin (1000mg PO QID) for seven days Cephalexin: 1000 mg PO QID for 7 days	Standard Dose Cephalexin n=31 participants at risk The comparator is standard-dose cephalexin (500mg PO QID) plus oral placebo for seven days Cephalexin: 500 mg PO QID plus oral placebo for 7 days
Gastrointestinal disorders Nausea or vomiting	9.7% 3/31 • Patients were assessed for adverse events during the day 7 and day 14 study follow-ups	3.2% 1/31 • Patients were assessed for adverse events during the day 7 and day 14 study follow-ups
Gastrointestinal disorders Diarrhea	16.1% 5/31 • Patients were assessed for adverse events during the day 7 and day 14 study follow-ups	6.5% 2/31 • Patients were assessed for adverse events during the day 7 and day 14 study follow-ups
Gastrointestinal disorders Abdominal pain	3.2% 1/31 • Patients were assessed for adverse events during the day 7 and day 14 study follow-ups	0.00% 0/31 • Patients were assessed for adverse events during the day 7 and day 14 study follow-ups
Skin and subcutaneous tissue disorders Rash	3.2% 1/31 • Patients were assessed for adverse events during the day 7 and day 14 study follow-ups	6.5% 2/31 • Patients were assessed for adverse events during the day 7 and day 14 study follow-ups
Product Issues Other	6.5% 2/31 • Patients were assessed for adverse events during the day 7 and day 14 study follow-ups	9.7% 3/31 • Patients were assessed for adverse events during the day 7 and day 14 study follow-ups

Additional Information

Krishan Yadav

Ottawa Hospital Research Institute

Phone: 613-798-5555

Email: kyadav@toh.ca

Results disclosure agreements

• Principal investigator is a sponsor employee
• Publication restrictions are in place