The Association Between Incorrect Use of Antibiotic Prophylaxis and in-Hospital Surgical Site Infections – A Prospective Observational Study

Figures & data

Table 1 Socio-Demographic Characteristics of the Study Participants

Variables	Categories	Frequency	Percentage
Age	Age of 18 to 34 years	151	56.1
	Age of 35 to 65 years	91	33.8
	Age of >65 years	27	10.0
	Mean age ±SD	41.95 ± 17.764 (18 to 90)
Sex	Male	179	66.5
	Female	90	33.5
Residence	Rural	149	55.4
	Urban	120	44.6
Smoking status (current)	Yes	32	11.9
	No	237	88.1

Table 2 Clinical Characteristics of the Study Participants

Variables	Categories	Frequency	Percentages
ASA class	I	116	43.1
	II	90	33.5
	III	35	13.0
	IV	28	10.4
Co-morbid condition	Yes	110	40.9
	No	159	59.1
Types of admission	Emergency	131	48.7
	Elective	138	51.3
CDC wound class	Class I (Clean wound)	48	17.8
	Class II (Clean contaminated)	90	33.5
	Class III (Contaminated)	35	13.0
	Class IV (Dirty wound)	96	35.7
Amount of blood loss	< 1500 mL	155	57.6
	≥1500 mL	4	1.5
	Unknown (not recorded)	110	40.9
Charlson co-morbidity index (CCI)	Low risk (0–2)	197	73.2
	Moderate risk (3–4)	41	15.2
	High risk (≥5 CCI)	31	11.5
Duration of operation	≤1 hour	85	31.6
	>1 hour	140	52.0
	Not recorded	44	16.4
	Mean±SD (minim- maximum)	90.21±52.22 (10 to 368 minutes)

Table 3 Medication History and Incorrect Use of Antibiotic Prophylaxis

Variables	Categories	Frequency		%
The pattern of prophylaxis antibiotic use (N= 269)	Ceftriaxone IV	142		52.8
	(Ceftriaxone + metro) IV	65		24.2
	(Chloramphenicol + ampicillin) IV	11		4.1
	(Ampicillin + metro) PO + (ceftriaxone + metro) IV	4		1.5
	Crystalline penicillin (IV)	8		3.0
	Ceftriaxone IV, amoxicillin PO	3		1.1
	(Amoxicillin + metro) PO + (ceftriaxone + metro) IV	17		6.3
	Ceftriaxone IV, ciprofloxacin PO	2		0.7
	Cloxacillin IV	6		2.2
	Ciprofloxacin	3		1.1
	(Amoxicillin + metro) PO + ceftriaxone IV	2		0.7
	Ceftriaxone, cloxacillin	2		0.7
	Other*	4		1.5
Number of AP used(N=269)	One	160		60.4
	Two	85		32.1
	Three	24		8.9
Route of AP administration (N= 269)	IV only	240		89.22
	Oral only	1		0.37
	Both oral and IV	28		10.41
History of antibiotic exposure in the past 3 months (N= 269)	Yes	53		19.7
	No	164		61.0
	Unknown	52		19.3
History of pre-admission medication (N= 269)	Yes	52		19.3
	No	216		80.3
	Unknown	1		0.4
Poly-pharmacy status (N= 269)	Yes	42		15.6
	No	227		84.4
Total antibiotic exposure in hospital (prophylaxis + other use)(N= 269)	≤ 2	206		76.6
	≥ 3	63		23.4
	Mean (SD); minimum to maximum	2.02 (1.026); 1 to 6
Cause for incorrect use of AP (N= 269)	Right selection	215	79.9
	Right selection + dose	102	37.9
	Right selection + dose + timing	71	26.4
	Right selection + dose+ timing + duration	55	20.4
	Right selection + dose + timing + duration + route	53	19.7
Intra-operative antibiotic re-dosing (N=14)	Yes	2	14.29
	No	12	85.71

Notes: N.B: *= (augumentin PO), (Chloramphenicol + ampicillin, Chloramphenicol+ cloxacillin), (Chloramphenicol+ cloxacillin), (ceftriaxone, ampicillin). Key: metro- metronidazole, PO- per oral, IV–intravenous, + (plus) - indicate concurrent use, (comma in a table)- indicate switch between each other, medication enclosed in bracket () indicate antibiotic used by individual patients.

Table 4 SSI and Associated Factor for Selecting Candidate Variables for Multivariate Analysis

Predictor Variables	Categories	The Outcome Variable (SSI)		COR	95% CI	p-value
		No (%)	Yes (%)
Sex	Male	148 (82.7)	31(17.3)	1	–	–
	Female	76(84.4)	14(15.6)	0.974	0.386–2.457	0.974
Age	Age of 18 to 40	127(84.1)	24(15.9)	1	–	–
	Age of > 40	97(82.2)	21(17.8)	1.564	0.617–3.969	0.346
Residence	Rural	124(83.2)	25(16.8)	1	–	–
	Urban	100(83.3)	20(16.7)	0.888	0.384–2.051	0.780
Smoking status	No	195(82.3)	42(17.7)	1	–	–
	Yes	29(90.6)	3(9.4)	0.661	0.159–2.741	0.568
ASA class	ASA class I–II	182(88.3)	24(11.7)	1	–	–
	ASA class III–IV	42(66.7)	21(33.3)	5.697	2.220–14.614	0.000
Co-morbid condition	No	130(81.8)	29(18.2)	1	–	–
	Yes	94(85.5)	16(14.5)	1.841	0.732–4.628	0.194
Type of admission	Elective	118(85.5)	20(14.5)	1	–	–
	Emergency	106(80.9)	25(19.1)	0.983	0.348–2.773	0.974
CDC wound class	Class I	43(89.6)	5(10.4)			0.881
	Class II	75(83.3)	15(16.7)	0.892	0.220–3.615	0.873
	Class III	29(82.9)	6(17.1)	0.955	0.175–5.224	0.958
	Class IV	77(80.2)	19(19.8)	0.647	0.160–2.622	0.542
Poly-pharmacy status	No	192(84.6)	35(15.4)	1	-	-
	Yes	32(76.2)	10(23.8)	0.463	0.159–1.350	0.158
Charlson CI	No CCI (0 score)	74 (76.3)	23(23.7)	1	–	–
	Yes CCI (≥ 1score)	150 (87.2)	22(12.8)	1.94	0.775–4.86	0.157
Overall LOS	≤7 days	36(92.3)	3(7.7)	1	–	0.409
	> 7 to ≤15 days	65(92.9)	5(7.1)	1.1218	0.171–7.466	0.900
	>15 days	123(76.9)	37(23.1)	0.190	0.043–0.834	0.028
After surgery LOS	≤ 7days	63(92.6)	5(7.4)	1	–	0.619
	>7 to≤15 days	88(87.1)	13(12.9)	0.721	0.146–3.563	0.688
	>15 days	73(73.0)	27(27.0)	1.299	0.205–8.219	0.781
Before surgery LOS	≤7 days	163(82.3)	35(17.7)	1		0.530
	> 7 to ≤15 days	25(92.6)	2(7.4)	0.400	0.066–2.426	0.319
	> 15 days	36(81.8)	8(18.2)	0.570	0.150–2.162	0.408
Duration of surgery	≤ 1 hour	69(81.2)	16(18.8)	1	–	0.281
	> 1 hour	122(87.1)	18(12.9)	0.509	0.195–1.325	0.166
	Not recorded	33(75.0)	11(25.0)	1.126	0.322–3.930	0.853
Correct selection +dose+ timing + duration + route of AP	All criteria correct	42(79.2)	11(20.8)	1	–	–
	At least one criteria not correct	182(84.3)	34(15.7)	4.714	1.388–16.007	0.013

Abbreviations: COR, crude odds ratio; LOS, length of hospital stay; AP, antibiotic prophylaxis.

Table 5 Independent Predictors of in-Hospital SSIs

Predictor Variables	Categories	Outcome Variable (SSI)		COR	AOR	95% CI	p-value
		No (%)	Yes (%)
ASA class	ASA class I–II	182(88.3)	24(11.7)	1	1	–	–
	ASA class III–IV	42(66.7)	21(33.3)	5.427	4.658	2.159–10.048	0.000
Charlson CI	No CCI (0 score)	74 (76.3)	23(23.7)	1	1	–	0.016
	Yes CCI (≥1score)	150 (87.2)	22(12.8)	0.597	0.366	0.174–0.769	0.008
Correct selection +dose+ timing + duration + route of AP	All criteria correct	42(79.2)	11(20.8)	1	1	–	–
	At least one criteria not correct	182(84.3)	34(15.7)	4.793	3.218	1.160–8.926	0.025

Abbreviations: COR, crude odds ratio; AOR, adjusted odds ratio.