Table 1. Characteristics of Included Studies.

Study	Design	No. of participant	Association with delay	Optimal timing (hr)	Conclusion
Mortality
Pincus et al. (2017)14)	Retrospective	42,230	+	24	30-day postoperative mortality rate was significantly lower in patients who underwent surgery within 24 hours of admission.
Uzoigwe et al. (2013)9)	Prospective	2,056	+	24	Postoperative mortality was significantly higher for surgery performed 36 hours after admission.
Shiga et al. (2008)15)	Systemic review	257,367	+	48	Postoperative 30-day and 1-year mortality increased due to delayed surgery of over 48 hours.
Moja et al. (2012)16)	Systemic review	191,873	+	24	Surgery within 24-48 hours of admission was rated as a major factor in reducing all-cause mortality.
Simunovic et al. (2010)17)	Systemic review	13,478	+	24	Earlier surgery within 24 hours was associated with a significant reduction in mortality.
Al-Ani et al. (2008)10)	Prospective	850	-	N	No difference in mortality among surgeries performed within 24, 36, and 48 hours of admission.
Moran et al. (2005)13)	Prospective	2,660	-	96	Delayed surgery of up to 4 days after admission had no effect on postoperative mortality.
Vidán et al. (2011)8)	Prospective	2,250	-	120	Delayed surgery of up to 120 hours after admission had no effect on postoperative mortality, after controlling confounders such as old age, dementia, and chronic disease.
Orosz et al. (2004)19)	Prospective	1,178	-	N	Early surgery was not associated with improved function or mortality.
Khan et al. (2009)20)	Systemic review	291,413	-	48	Early surgery and postoperative survival rates were not closely associated, after adjusting for various associated factors.
Hospital stay
Siegmeth et al. (2005)21)	Prospective	3,628	+	48	The length of hospital stay shortened at an average of 10.9 days in patients who underwent surgery within 48 hours.
Al-Ani et al. (2008)10)	Prospective	850	+	24	The average length of hospital stay was reduced by 4 days in patients who underwent surgery within 24 hours after admission.
Lefaivre et al. (2009)22)	Retrospective	465,000	+	48	Elderly patients with a fracture of the hip should be stabilised surgically within the first 48 hours in order to minimise the delay to discharge and hospital morbidity.
Vidán et al. (2011)8)	Prospective	2,250	+	120	Significant positive correlation between delayed surgery for more than 5 days and prolongation of hospital stay.
Postoeprative complication
Grimes et al. (2002)23)	Retrospective	1,383	+	24	The incidence of pressure sores was significantly increased when the operation was delayed by more than 96 hours.
Moja et al. (2012)16)	Systemic review	191,873	+	24	Surgical delay is associated with a significant increase in the risk of pressure sores.
Simunovic et al. (2010)17)	Systemic review	13,478	+	24	Earlier surgery was associated with a lower rates of postoperative pneumonia and pressure sores among elderly patients with hip fracture.
Smektala et al. (2008)12)	Prospective	2,916	+	12	Shorter time-to-surgery may be associated with somewhat lower rates of post-operative complications, such as decubitus ulcers, urinary tract infections, thromboses, pneumonia, and cardiovascular events, and with somewhat higher rates of others, such as postoperative bleeding or implant complications.
Shin et al. (2016)24)	Retrospective	0.208	+	24	The prevalence of venous thromboembolism in 23 of 208 patients (11.1%) with hip fracture whose operation was delayed for more than 24 hours.
Al-Ani et al. (2008)10)	Prospective	0.85	+	36	Surgery performed within 36 hours increased the likelihood of returning to independent daily life within 4 months.
Doruk et al. (2004)25)	Retrospective	0.065	+	120	Early postoperative weight-bearing recovery and a return to daily activities could be achieved if surgery was performed within 5 days of admission.