. 2020 Oct 14;15(10):e0240431. doi: 10.1371/journal.pone.0240431

Table 2. The summary of the risk factors for PLP and their measures of association with PLP.

Author	Population	Outcome	Risk factor(s)	Measures of association	Strength of association
Ahmed et al., 2017	Cancer patients who had undergone limb amputations	PLP	Post-amputation depression	3.86 (1.75–8.53)^‡	Strong
			Pre-amputation pain	2.83 (1.38–5.76)^‡	Moderate
			Stump pain	31.2 (8.97–108.50)^‡	Very strong
			Use of prosthesis	2.83 (1.19–4.76)^‡	Moderate
			Sleep disturbance	21.43 (8.28–55.43)^‡	Very strong
Buchanan et al., 1986	Amputees who were receiving routine prosthetic services	PLP	Age	0.12 (p<0.01)^¥	Weak
Desmond et al., 2010	Members of the British Limbless Ex-Service Men’s Association	PLP	Stump pain	11.17 (p<0.01)^‡	Very strong
Dijkstra et al., 2002	Amputees who were receiving routine prosthetic services	PLP	Diabetic cause of amputation	4 (p<0.001)^‡	Strong
			Proximal site of amputation	1.60 (0.038)^‡	Moderate
			Lower limb amputation	5.60 (p<0.001)^‡	Strong
			Bilateral amputations	8.20 (p = 0.01)^‡	Strong
			Stump pain	3.90 (p<0.001)^‡	Strong
			Phantom sensations	19.50 (p<0.001)^‡	Very strong
Ephraim et al., 2005	Amputees who had contacted the Amputee Coalition of America (ACA) between 1998 and 2000	PLP	Post-amputation depression	2 (1.3–3.1)^‡	Moderate
			Lower limb amputation	2.50 (1.3–4.7)^‡	Moderate
			2 or more comorbidities	2.70 (1.3–5.8)^‡	Moderate
			Widow	2.70 (1.1–6.5)^‡	Moderate
Gallagher et al., 2001	Amputees who were attending the Limb Fitting Clinic.	PLP	Proximal site of amputation	15.65 (p<0.001)^‡	Very strong
			Traumatic cause of amputation	14.60 (p<0.002)^‡	Very strong
			Sex (male)	3.76 (p<0.05)^‡	Strong
			Other medical problems	5.93 (p<0.02)^‡	Strong
			Lack of pre-amputation counselling	4.74 (p<0.03)^‡	Strong
Hanley et al., 2009	Patients who had undergone upper-limb amputation 6 months or more before recruitment	PLP	Use of prosthesis	4.23 (p<0.05)^¶	Moderate
Hanley et al., 2006	Patients who had undergone lower limb amputation	PLP	Pre-amputation pain	0.48 (p<0.01)^§	Weak
Hanley et al., 2006	Patients who had undergone lower limb amputation	PLP	Stump pain	0.53 (p<0.0001)^§	Weak
Kooijman et al., 2000	Amputees using upper limb prosthesis	PLP	Phantom sensations	11.30 (p = 0.001)^†	Very strong
Kooijman et al., 2000	Amputees using upper limb prosthesis	PLP	Stump pain	1.90 (p = 0.015)^†	Weak
Larbig et al., 2019	Patients who had undergone upper or lower limb amputations	PLP	Pre-amputation depression	2.05 (p<0.05)^§	Moderate
			Pre-amputation pain	4.22 (p<0.01)^§	Moderate
			Stump pain	3.90 (p<0.01)^§	Moderate
Noguchi et al., 2019	Patients who had undergone upper or lower limb amputations	PLP	Diabetic cause of amputation	2.24 (p = 0.032)^‡	Moderate
Noguchi et al., 2019	Patients who had undergone upper or lower limb amputations	PLP	Pre-amputation pain	6.36 (p = 0.024)^‡	Strong
Razmus et al., 2017	Occupants of the nursing home, and clients of the Public Institute of Orthopaedic Equipment	PLP	Phantom sensations	4.94 (P<0.05)^§	Strong
Richardson et al., 2007	Patients who had undergone amputation of the lower limb due to peripheral vascular disease.	PLP	Stump pain	7.03 (1.34–36.82)^‡	Strong
			Increased ability to move the phantom limb.	8.31 (1.54–44.79)^‡	Strong
			Praying/hoping	2.86 (1.68–13.18)^‡	Moderate
			Catastrophizing	3.28 (1.71–14.91)^‡	Strong
			Passive coping	4.60 (6.50–25.00)^‡	Strong
Wartan et al., 1997	Traumatic amputees	PLP	Phantom sensations	107.30 (p<0.0001)^§	Strong
Yin et al., 2017	Amputees who underwent limb amputations at a tertiary hospital	PLP	Pre-amputation pain	10.40 (p = 0.002)^‡	Very strong
Yin et al., 2017		PLP	Post-amputation epidural analgesia	4.90 (p = 0.008)^‡	Strong

¥ _{Point-biserial correlation analysis;}

_{¶ Pearson’s univariate correlation test;}

_{§ Chi-squared;}

_{† Relative risk;}

‡ _{Odds ratio.}