Association between anemia and the risk of diabetic foot ulcer: A meta-analysis

Table 1 Characteristics of the included studies

Ref.	Country	Design	No. of patients with DM	Mean age (years)	Men (%)	Duration of diabetes (years)	No. of patients with DFU	Definition of anemia	Outcomes reported	Variables matched or adjusted
Hokkam et al[16], 2009	Egypt	CC	300	57.6	58.7	17.1	180	NR	OR of anemia	Age, duration of diabetes, insulin use, and smoking
Khanbhai et al[17], 2012	UK	CC	40	65	60	NR	10	NA	Difference of HGB	None
Jiang et al[18], 2015	China	CC	1333	58.7	58.8	8.7	452	NA	Difference of HGB and OR per 1-g/dL decrease of HGB	Age, sex, BMI, blood lipids, smoking, diabetic complications, OADs, and insulin use
Alsayegh et al[19], 2017	Kuwait	CS	1580	52.3	50.3	NR	429	Males < 13 g/dL, females < 12 g/dL	OR of anemia	None
Shareef et al[20], 2019	Pakistan	CC	322	NR	73.9	NR	161	Males < 13 g/dL, females < 12 g/dL	Difference of HGB and OR of anemia	Age, sex, blood lipids, and HbA1c
Shi et al[21], 2021	China	CC	1001	58.7	71.5	10.8	494	NA	Difference of HGB	None
Shi et al[21], 2021	China	CC	487	61.7	71.7	9.5	231	NA	Difference of HGB	None
Jiang et al[22], 2022	China	CS	853	60.5	69.2	11.7	369	NA	OR per 1-g/dL decrease of HGB	Age, sex, duration of DM, smoking, diabetic complications, and comorbidities
Ardelean et al[24], 2023	Romania	CS	112	63.8	66.1	NR	80	NA	Difference of HGB	Age, sex, BMI, and DM duration
Li et al[25], 2023	China	CS	334	67.3	52.1	9.8	84	NA	Difference of HGB	None
Li et al[26], 2023	China	CS	145	67.9	53.8	12.1	80	NA	Difference of HGB and OR per 1-g/dL decrease of HGB	Age, sex, DM duration, Scr, HbA1c, Alb, TC and CRP
Afrid et al[23], 2023	Pakistan	CS	371	42.6	73.4	8.7	97	Males < 13 g/dL, females < 12 g/dL	OR of anemia	None
Rupasinghe et al[30], 2024	Sri Lanka	CS	252	56.9	48.8	NR	18	Males < 13 g/dL, females < 12 g/dL	OR of anemia	None
Zaki et al[31], 2024	Saudi Arabia	CS	100	60	74	NR	81	Males < 13 g/dL, females < 12 g/dL	OR of anemia	None
Fan et al[28], 2024	US	CS	161834	65.8	62.4	NR	47604	Database codes of IDA	OR of anemia	Age, sex, comorbidities, and ethnicity
Cao et al[27], 2024	US	CS	1673	64.7	52.6	NR	136	Males < 13 g/dL, females < 12 g/dL	OR of anemia	Age, sex, race and ethnicity, BMI, comorbidities, smoking, alcohol drinking, blood lipids, HbA1c, and serum ferritin
Jiang et al[29], 2024	China	CS	212	65	53.3	11.3	105	NA	Difference of HGB and OR per 1-g/dL decrease of HGB	Age, sex, DM duration, PAD, smoking, blood lipids, and SCr

Alb: Albumin; BMI: Body mass index; CC: Case-control; CRP: C-reactive protein; CS: Cross-sectional; DFU: Diabetic foot ulcer; DM: Diabetes mellitus; HbA1c: Hemoglobin A1c; HGB: Hemoglobin; NR: Not reported; OR: Odds ratio; PAD: Peripheral artery disease; SCr: Serum creatinine; TC: Total cholesterol.

Table 2 Study quality evaluation via the Newcastle-Ottawa scale

Ref.	Adequate definition of cases	Representativeness of cases	Selection of controls	Definition of controls	Control for age	Control for other confounders	Exposure ascertainment	Same methods for events ascertainment	Non-response rates	Total
Hokkam et al[16], 2009	0	1	1	1	1	1	0	1	1	7
Khanbhai et al[17], 2012	1	0	1	1	0	0	1	1	1	6
Jiang et al[18], 2015	1	0	1	1	1	1	1	1	1	8
Alsayegh et al[19], 2017	1	1	1	1	0	0	1	1	1	7
Shareef et al[20], 2019	0	1	1	1	1	1	1	1	1	8
Shi et al[21], 2021	1	1	1	1	0	0	1	1	1	7
Jiang et al[22], 2022	1	0	1	1	1	1	1	1	1	8
Ardelean et al[24], 2023	0	1	1	1	1	1	1	1	1	8
Li et al[25], 2023	0	1	1	1	0	0	1	1	1	6
Li et al[26], 2023	1	0	1	1	1	1	1	1	1	8
Afrid et al[23], 2023	1	0	1	1	0	0	1	1	1	6
Rupasinghe et al[30], 2024	1	0	1	1	0	0	1	1	1	6
Zaki et al[31], 2024	1	0	1	1	0	0	1	1	1	6
Fan et al[28], 2024	0	0	1	1	1	1	0	1	1	6
Cao et al[27], 2024	1	0	1	1	1	1	1	1	1	8
Jiang et al[29], 2024	1	0	1	1	1	1	1	1	1	8