Preoperative and intraoperative risk factors for acute kidney injury after hip fracture surgery: a cohort retrospective study

Figures & data

Table 1. Patients characteristics.

Characteristic	Post-operative AKI N = 126	Non-AKI N = 485	Total N = 611	p Value
Age	78.37 ± 9.69	75.94 ± 9.63	76.44 ± 9.68	.012*
Gender (female (%))	57 (45.2)	246 (54.4)	321 (52.54)	.081
Estimated GFR	65.24 ± 22.74	73.66 ± 23.45	71.92 ± 23.54	<.001*
Hb pre-OP	11.45 ± 1.87	12.00 ± 2.47	11.89 ± 2.37	.02*
Preoperative medication
ACEI/ARB use (%)	50 (39.68)	182 (37.52)	232 (37.39)	.73
Beta-blocker use (%)	64 (50.79)	215 (44.33)	279 (45.66)	.23
NSAID use	25 (19.84)	128 (26.39)	153 (25.04)	.16
Blood-transfusion pre operative	1 (0.79%)	2 (0.41%)	3 (0.49%)	.50
Comorbidities
DM (%)	69 (54.76)	232 (47.83)	301 (49.26)	.199
HTN (%)	92 (73.01)	319 (65.77)	411 (67.27)	.150
CVD (%)	54 (42.86)	158 (32.58)	212 (34.7)	.078
ND (%)	23 (18.25)	72 (14.84)	96 (15.38)	.64
Malignance (%)	10 (7.93)	34 (7.01)	44 (7.2	.86
Surgical characteristics
Type of fractur:				.02*
FN (%)	31 (24.6)	175 (36.08)	206 (33.71)
IT (%)	90 (71.4)	281 (57.93)	371 (60.72)
ST (%)	5 (3.97)	29 (5.98)	34 (5.56)
Type of surgery:				.03*
PHR (%)	31 (24.6)	172 (35.53)	203 (33.22)
IMN (%)	55 (43.65)	202 (43.65)	257 (49.9)
DHS (%)	40 (31.74)	110 (22.72)	150 (24.25)
Type of anesthesia:				.015*
Spinal (%)	98 (77.78)	320 (65.98)	418 (68.41)
General (%)	28 (22.22)	165 (34.02)	193 (31.59)
Anti-biotic:				.16
Cephalosporine based (%)	7 (5.55)	22 (4.53)	29 (4.76)
Cefuroxime +vancomycin (%)	114 (89.68)	417 (85.77)	531 (86.58)
vancomycin (%)	5 (3.97)	46 (9.48)	51 (8.35)
Postoperative characteristics
Length of hospitalities	10.65 ± 8.1	7.55 ± 4.46	8.19 ± 5.55	<.001*
Mortality (%)	35 (27.78)	51 (10.52)	86 (14.07)	<.001*
ICU admission (%)	48 (38.09)	111 (22.89)	159 (27.66)	<.001*
Blood transfusion post operative	13 (10.3)	27 (5.57)	40 (6.55%)	.090
Vasopressors use	5 (3.97%)	9 (1.86%)	14 (2.29%)	.319

Note: GFR: glomerular filtration rate; Hb pre-OP: hemoglobin preoperatively; ACEI/ARB: angiotensin-converting enzyme inhibitors/ angiotensin receptor blockers; NSAIDs: nonsteroidal anti-inflammatory drugs; DM: diabetes mellitus; HTN: hypertension; CVD: cardiovascular diseases; ND: neurological disease; FN: femur neck fracture; IT: intertrochanteric fracture; ST: subtrochanteric fracture; PHR: partial hip replacement; IMN: intramedullary nail; DHS: dynamic hip screw; ICU: intensive care unit; AKI: acute kidney injury.

Significant p values are highlighted in bold.

Figure 1. Flow chart for the surgery and type of fracture.

Table 2. Factors affecting the development of postoperative AKI.

Variable	Multivariate
	OR	95% CI	p Value
Age	1.01	0.98–1.04	.243
Preoperative HB	0.91	0.82–1.01	.081
Preoperative eGFR	0.988	0.979–0.997	.015*
Type of surgery:
DHS	1.31	0.91–1.91	.148
PHR	0.56	0.32–0.96	.036*
IMN	0.78	0.48–1.28	.33
Spinal anesthesia	1.78	1.11–2.87	.016*

Note: eGFR: estimated glomerular filtration rate; HB: hemoglobin; FN: femur neck fracture; IT: intertrochanteric fracture; ST: subtrochanteric fracture; PHR: partial hip replacement; IMN: intramedullary nail; DHS: dynamic hip screw; OR: odds ratio; CI: confidence interval.

Significant p values are highlighted in bold.

Table 3. Result of development postoperative AKI.

Variable	OR	95% CI	p Value
ICU admission	2.07	1.37–3.15	<.001*
Hospitalization	1.09	1.05–1.13	<.001*
Mortality	3.27	2.01–5.32	<.001*

Note: OR: odds ratio; CI: confidence interval; ICU: intensive care unit.

Significant p values are highlighted in bold.

Table 4. Factors affecting the mortality postoperatively.

Variable	Multivariate
	HR	95% CI	p Value
Age	1.04	1.01–1.07	.004*
Male	1.79	1.12–2.69	.012*
Preoperative HB level	0.83	0.74–0.93	.0014*
Preoperative eGFR	0.9879	0.98–0.9976	.015*
postoperative AKI	2.42	1.57–3.74	<.001*

Note: HR: hazard ratio; CI: confidence interval; HB: hemoglobin level; eGRF: estimated glomerular filtration rate; AKI: acute kidney injury.

Significant p values are highlighted in bold.

Figure 2. Kaplan Meier curve; AKIPostOP: acute kidney injury postoperatively; N: no; Y: yes; the red line represent the survival of the patients who didn’t develop postoperative AKI; the blue one represent the survival of the patients who developed postoperative AKI.

Table 5. Survival table.

Group	Overall	AKI	Non-AKI
Survival probability:
30 days	95.7%	90.5%	97.1%
60 days	95.3%	88.1%	97.1%
90 days	88.9%	74.6%	92.6%
180 days	85.9%	72.2%	89.5%

Note: AKI: acute kidney injury.