Multiplex PCR point of care testing versus routine, laboratory-based testing in the treatment of adults with respiratory tract infections: a quasi-randomised study assessing impact on length of stay and antimicrobial use

Table 4 Summary of secondary outcome measures

Outcome		Control	Intervention	Estimated intervention effect	Adjusted p value
Antibiotic use at any time during the hospital stay post-enrolment^a	Percentage	77% (152/198)	75% (243/324)	aOR (95% CI)1.0 (0.6, 1.5)	0.99
Duration of antibiotic usage (days)^b	median (IQR)	6.0 (5.0, 7.3)	6.0 (4.0, 7.0)	Absolute difference in natural logarithm of duration (95% CI)-0.08 (−0.22, 0.054)	0.23
Time to antibiotic within the first 72 h of stay (hours)^c	median (IQR)	0.0 (0.0–3.0)	0.0 (0.0–6.0)	Absolute difference in days (95% CI)2.2 (−1.4,5.8)	0.21
Readmission within 30 days of study participation^a	Percentage	20% (42/211)	19% (64/333)	aOR (95% CI)0.9 (0.6, 1.4)	0.70
Mortality 30 days post-enrolment^a	Percentage	4% (9/211)	4% (14/333)	aOR (95% CI)0.9 (0.3, 2.2)	0.79
Length of study ward inpatient stay (hours)^c	median (IQR)	54 (23, 99)	61 (24, 115)	Absolute difference in natural logarithm of length of stay (95% CI) 0.05 (−0.16, 0.25)	0.66

^aBased on a logistic regression analysis
^bAnalysed with a linear model (after log transformation)
^cAnalysed with a negative binomial regression
All models adjusted for age, sex, Charlson and Potts scores, day of week, and admission values of WCC and CRP and used multiple imputation to account for missing data. The CURB-65 score was not available for 59% of patients, and was therefore not adjusted for in statistical models. There was less than 5% missing data for all covariates. Missing outcome variables 1) Antibiotics within 72 h and 2) Antibiotics at any time: missing data for 13 patients in the control arm and 10 patients in the intervention arm, 3) Time to antibiotics in the first 72 h: missing data for 1 patient in the intervention arm, 4) duration of antibiotics: missing data for 4 patients in the control arm and 13 in the intervention arm, 5) readmission: missing data for 1 patient in intervention arm, 6) mortality: missing data for 1 patient in intervention arm

ISSN: 1471-2334