The impact of vancomycin trough concentrations on outcomes in non-deep seated infections: a retrospective cohort study

Table 2 Results (N = 103)

	Low Trough (N = 48)	High Trough (N = 55)	Odds Ratio	95% Confidence Interval	p-value
Clinical Outcomes
• Clinical Cure (Primary Outcome)	42 (88%)	48 (87%)	1.02	0.32–3.28	> 0.99
• Survival	48 (100%)	54 (98%)	2.67	0.11–67.13	> 0.99
• Readmission within 30 days for same indication as original course of vancomycin	0 (0%)	2 (4%)	0.22	0.01–4.71	0.50
Microbiological Outcome
• Patients With Positive Non-Screening Cultures for Resistant Gram positive Isolates^a identified up to 2 weeks after discontinuation of vancomycin	0	0	–	–	–
Vancomycin Use and Dosing
• Final Total Daily Dose, median^b (mg) (Range)	2000 (500–3000)	2000 (666–4500)			0.46
• Number of Patients With Daily Dose ≥3 g/day^c	4 (8%)	14 (25%)	0.27	0.08–0.88	0.04
• Initial Steady State Trough (mg/L)^d	7.13 ± 2.24	12.20 ± 5.30			<0.0001^e
• Final Steady State Trough (mg/L)^d	7.38 ± 1.95	16.56 ± 6.56^f			< 0.0001^f
• Duration of Vancomycin Therapy (days)^g	7 ± 3	7 ± 3			0.73
• # Patients Requiring Dose Adjustment	7 (15%)	22 (40%)	0.26	0.10–0.67	0.005
• # of Dose Adjustments Per Patient^b	0.17 ± 0.43	0.55 ± 0.79			0.02^f
• Time Estimate for Dose Adjustments Per Patient (minutes)^b	9 ± 23	29 ± 42			0.02^f
Renal Function Outcomes
• Final Serum Creatinine (mmol/L)	71 ± 28	83 ± 46			0.11^e
• % Change in Serum Creatinine	−5 ± 18	3 ± 30			0.13^e
• At Risk for Kidney Injury^h	0 (0%)	4 (7%)	0.12	0.01–2.25	0.12

^aMethicillin Resistant Staphylococcus aureus, Coagulase-negative Staphylococci, or Vancomycin Resistant Enterococci
^bFor non-normally distributed data, the median was reported rather than the mean ± standard deviation, with the exception of: # of Dose Adjustments Per Patient, and Time Estimate for Dose Adjustment Per Patient
^cNo patients in the low trough group and 2 patients in the high trough group received ≥4 g vancomycin per day
^dInitial vs. Final steady state trough concentration comparisons within groups: Low trough p-value = 0.5607 (equal SD, unpaired t-test); High trough p-value = 0.0009 (unequal SD, unpaired t-test Welch Corrected)
^eUnequal SD, unpaired t-test Welch Corrected
^fDid not pass test for normality, two tailed Mann-Whitney U test used
^gPatients were included if the intent was to treat for ≤14 days (2 patients in the high trough group were treated for 15 days)
^h≥50% increase from baseline serum creatinine as per RIFLE Criteria [5]

ISSN: 2050-6511