. 2020 Aug 17;4(1):e00175. doi: 10.1002/edm2.175

TABLE 3.

Outcomes and results of included studies

Publication	Outcome	Results in multivariate analyses	Covariates
Abbott et al (1998) ²⁴	FU	stat. sign.: age (HR 0.957), PN (1.050), VPT (1.056); not stat. sign.: type of diabetes, ethnicity, economic status, duration of diabetes	Age, PN, VPT, type of diabetes, ethnicity, economic status, duration of diabetes
Al‐Rubeaan et al (2015) ²⁵	Any DF (FU, FG, LEA)	stat. sign.: age (≥45 y: OR 3.81 [95% CI: 2.22‐6.54], P < .0001), male gender (1.92 [1.49‐2.48], P < .0001), PN (7.20 [4.84‐10.71], P < .0001), duration of diabetes (≥10 y: 2.50 [1.66‐3.77], P < .0001), insulin use (3.98 [3.02‐5.23], P < .0001), retinopathy (1.84 [1.43‐2.35], P < .0001), poor glycaemic control (1.49 [1.12‐1.98], P = .006); not stat. sign.: Charcot joint, PVD, nephropathy, cerebral vascular disease, coronary heart disease, hypertension, smoking	Age, gender, Charcot joint, PVD, PN, duration of diabetes, insulin use, retinopathy, nephropathy, glycaemic control, cerebral vascular disease, coronary heart disease, hypertension, smoking
Anderson et al (2018) ²⁶	FU	stat. sign.: social deprivation (highest quintile of deprivation compared to lowest quintile) (OR 1.77 [95% CI: 1.45‐2.14], P < .0001) in T2DM only: increased deprivation per quintile (1.13 [1.09‐1.16], P < .0001); not stat. sign.: increased deprivation per quintile in patients with T1DM	Age, gender, social deprivation
Baba et al (2014) ²⁷	FU	Risk factors for active FU at baseline: stat. sign.: intermittent claudication (OR 17.24 [95% CI 3.66‐81.23), P < .001), duration of diabetes (per increase of 5 y: 1.58 [1.12‐2.23], P = .009), PN (15.84 [1.95‐128.81], P = .010), antihypertensive therapy (11.16 [1.13‐95.44], P = .028) not stat. sign.: age, exercise, diabetes treatment, microalbuminuria, PVD, history of vascular bypass Risk factors for hospitalization for FU during follow‐up: stat. significant: retinopathy (OR 3.86 [95% CI 2.26‐6.59], P < .001), cerebrovascular disease (3.76 [1.97‐7.19], P < .001), intermittent claudication (2.77 [1.52‐5.04], P = .001), PN (2.24 [1.35‐3.71), P = .002), HbA1c (for a 1% increase: 1.22 [1.07‐1.40], P = .003), alcohol consumption (for 1 standard drink/day increase: 1.16 [1.05‐1.27], P = .003), decreased eGFR (2.12 [1.30‐3.51], P = .004), PVD (1.85 [1.10‐3.13], P = .021), pulse pressure (for a 5 mmHg increase: 1.07 [1.00‐1.14], P = .038); not stat. sign.: duration of diabetes, fasting plasma glucose, diabetes treatment, systolic blood pressure, albuminuria, history of vascular bypass	For end‐point active ulcer at baseline: age, exercise, duration of diabetes, diabetes treatment, antihypertensive therapy, PN, intermittent claudication, PVD, history of vascular bypass For end‐point hospitalization for FU during follow‐up: duration of diabetes, alcohol consumption, fasting plasma glucose, HbA1c, diabetes treatment, systolic blood pressure, pulse pressure, albuminuria, nephropathy, retinopathy, PN, intermittent claudication, PVD, cerebrovascular disease, history of vascular bypass
Bruun et al (2013) ²⁸	FU, LEA	Risk factors for FU at baseline: stat. sign.: male gender (OR 2.45 [95% CI 1.01‐5.98], P < .05), PN (2.51 [1.30‐4.85], P < .01), retinopathy (6.21 [2.13‐18.10], P < .001), PVD (3.22 [1.46‐7.13], P < .01); not stat. sign.: age, impaired vision or blindness, microalbuminuria, proteinuria, stroke, myocardial infarction, angina/ischaemic heart disease, mental disorder Risk factors for FU at 6‐year follow‐up: stat. sign.: PN (2.72 [1.24‐5.96], P < .05), PVD (2.84 [1.10‐7.37], P < .05), myocardial infarction (4.36 [1.60‐11.91], P < .01); not stat. sign.: age, gender, retinopathy, impaired vision or blindness, microalbuminuria, proteinuria, stroke, angina/ischaemic heart disease, heart failure, cancer, mental disorder Risk factors for FU at 14‐year follow‐up: stat. sign.: PN (5.60 [1.98‐15.88], P <.01), PVD (5.15 [1.59‐16.74], P < .01), myocardial infarction (3.40 [1.07‐10.81], P < .05), heart failure (4.76 [1.40‐16.15], P < .05); not stat. sign.: age, gender, retinopathy, impaired vision or blindness, microalbuminuria, proteinuria, stroke, angina/ischaemic heart disease, mental disorder Risk factors for any amputation during follow‐up: male gender (HR 2.40 [95% CI 1.31‐4.41], P < .01), PN (2.09 [1.19‐3.69], P < .05), retinopathy (6.42 [2.59‐15.90], P < .001), impaired vision or blindness (6.92 [2.35‐20.38], P < .001), microalbuminuria (2.11 [1.21‐3.67], P < .01), PVD (3.43 [1.65‐7.12], P < .001), myocardial infarction (2.79 [1.01‐7.75], P < .05); not stat. sign.: age, proteinuria, stroke, angina/ischaemic heart disease, heart failure, cancer, mental disorder	Age, gender, duration of diabetes, living alone, education, smoking, HbA1c, BMI, hypertension, PN, retinopathy, impaired vision or blindness, microalbuminuria, proteinuria, PVD, stroke, myocardial infarction, angina/ischaemic heart disease, heart failure, cancer, mental disorder
Bruun et al (2014) ²⁹	FU, LEA	Risk factors for FU at 6‐year follow‐up: stat. sign.: patient's motivation reported by GP (poor vs very good: OR 12.37 [95% CI 1.22‐25.23], P < .05), patient's own effort reported by GP (poor vs good: 6.24 [2.16‐18.01], P < .05); not stat. sign.: patient‐reported effort, influence of life circumstances as reported by GP Risk factors for any amputation during 13‐year follow‐up: stat. sign.: patient's own effort reported by GP (poor vs good: HR 4.17 [95% CI 1.67‐10.45], P < .01), life circumstances as reported by GP (none in particular vs good: 2.96 [1.07‐8.22], P < .05; poor vs good: 2.60 [1.03‐6.54], P < .05); not stat. sign.: patient's motivation reported by GP, patient‐reported effort	Age, gender, duration of diabetes, living alone, education, smoking, HbA1c, BMI and hypertension, patient's motivation reported by GP, patient's effort reported by GP, patient‐reported effort, influence of life circumstances as reported by GP
Callaghan et al (2011) ³⁰	LEA	stat. sign.: triglycerides (150‐199 vs < 150 mg/dL: HR 1.29 [95% CI 1.07‐1.55]; 200‐499 vs < 150 mg/dL: 1.40 [1.19‐1.65]; >500 vs < 150 mg/dL: 1.65 [1.22‐2.24]), LDL (>160 vs < 100 mg/dL: 1.30 [1.03‐1.64]), HDL (>60 vs < 40 mg/dL: 1.37 [1.02‐1.84]), male gender (1.59 [1.33‐1.90]), ethnicity (Asian vs white: 0.51 [0.39‐0.69]), duration of diabetes (10‐19 vs < 10 y: 1.94 [1.65‐2.28], >20 vs < 10 y: 2.38 [1.96‐2.88]), diabetes therapy (T2DM on insulin vs diet only: 2.41 [1.88‐3.10], T2DM on oral OHA vs diet only: 1.62 [1.28‐2.05]), BMI (obese vs normal weight: 0.80 [0.65‐0.98]), height (2nd vs 1st quartile: 1.43 [1.09‐1.86], 3rd vs 1st quartile: 1.34 [1.01‐1.77], 4th vs 1st quartile: 1.98 [1.48‐2.66]), hypertension (1.51 [1.27‐1.78]), PN (2.60 [2.23‐3.04]), retinopathy (1.85 [1.15‐2.98]), heart attack (1.27 [1.06‐1.52]), stroke (1.97 [1.55‐2.50]), end‐stage renal disease (4.29 [3.06‐6.03]); not stat. sign.: LDL (100‐129 and 130‐159 both vs < 100 mg/dL), HDL (40‐59 vs < 40 mg/dL), age, ethnicity (African American, Hispanic, Mixed/Other, all vs White), HbA1C, statin medication, fibrate/niacin medication, smoking, BMI (underweight and overweight, both vs normal weight)	Age, gender, ethnicity, triglycerides, LDL, HDL, education, income, whether lives in working class neighbourhood, smoking, alcohol use, BMI, height, adherence to guidelines for self‐monitoring of blood glucose, exercises, statin medication, fibrate/niacin medication, family history of diabetes, duration of diabetes, HbA1C, type of diabetes and therapy, history of hypertension, neuropathy, retinopathy, nephropathy, stroke or heart attack, end‐stage renal disease
Chaturvedi et al (2001) ³¹	FG and/or LEA	stat. sign.: ethnicity (American Indian vs European: RR 2.78 [95% CI 1.66‐4.66])	Age, duration of diabetes, gender, ethnicity, ECG, plasma glucose, systolic blood pressure, proteinuria, retinopathy, triglyceride
Chen et al (2017) ³²	FU	stat. sign.: indirect bilirubin (≥ 6 μmol/l vs < 6 μmol/l: OR 0.75 [95% CI 0.57‐0.98], P = .029); not stat. sign.: total bilirubin, direct bilirubin	Age, gender, smoking, alcohol, BMI, HbA1C, WBC, ALT, AST, GGT, triglycerides; model for analysis of direct bilirubin in addition adjusted for indirect bilirubin, and vice versa
Chen et al (2018) ³³	FU	stat. sign.: VEGF‐A (lower 1st tertile vs upper 3rd tertile: OR 1.76 [95% CI 1.01‐3.07], analysed as continuous variable per 10‐unit increase: 0.93 [0.88‐0.97]), PlGF (lower 1st tertile 1 vs upper 3rd tertile: 2.36 [1.34‐4.15], analysed as continuous variable per 5‐unit increase: 0.96 [0.94‐0.99]); not stat. sign.: VEGF‐A (middle 2nd tertile vs upper 3rd tertile), PlGF (middle 2nd tertile vs upper 3rd tertile)	Age, gender, duration of diabetes, education, BMI and smoking, VEGF‐A, PlGF
Dekker et al (2016) ³⁴	FU, CA	Risk factors for FU: stat. sign.: age (for every year increase: OR 0.991 [95% CI 0.985‐0.997], P = .003), retinopathy (1.357 [1.154‐1.595], P < .001), PN (3.441 [2.94‐4.027], P < .001), hypertension (2.265 [1.586‐3.237], P < .001), PVD (4.309 [3.668‐5.062], P < .001), coronary artery disease (1.388 [1.178‐1.635], P << .001], chronic kidney disease (1.824 [1.541‐2.158], P < .001); not stat. sign.: number of HbA1cs drawn, most recent BMI Risk factors associated with CA: stat. sign.: age (for every year increase: 0.964 [0.938‐0.99], P = .008), hypertension (2.571 [1.213‐4.131], P = .018), PN (1.233 [1.035‐3.038], P = .049); not stat. sign.: number of HbA1cs drawn, most recent BMI, retinopathy, PVD, coronary artery disease, chronic kidney disease	Age, number of HbA1Cs drawn BMI, retinopathy, neuropathy, hypertension, PVD, coronary artery disease, chronic kidney disease
Hippisley‐Cox et al (2016) ³⁵	LEA	stat. sign.: metformin (HR 0.70 [95% CI 0.64‐0.77]), insulin (1.64 [1.41‐1.91]) (HR for each diabetes drug group is compared with no prescription of that particular medicine); not stat. sign.: glitazones, gliptins, sulphonylureas, other OHA	Age, gender, ethnicity, calendar year, duration of diabetes, deprivation, smoking, use of anticoagulants, thiazides, ACE inhibitors, angiotensin 2 blockers, calcium channel blockers, statins, aspirin, blindness, hyperglycaemia, hypoglycaemia, severe kidney failure, hypertension, CVD, atrial fibrillation, nephropathy, rheumatoid arthritis, valvular heart disease, PVD, BMI, systolic blood pressure, HbA1c, creatinine, cholesterol:HDL ratio, each of the other diabetes drugs
Hu et al (2012) ³⁶	FU	stat. sign.: skin autofluorescence (OR 2.55 [95% CI 1.10‐5.91], P = .03), triglycerides (0.31 [0.13‐0.74], P < .01), BUN (1.22 [1.02‐1.46], P = .03), right ABI (0.001 [0.000‐0.04], P < .01), C‐reactive protein (1.02 [1.001‐1.03], P = .03); not stat. sign.: duration of diabetes, age, left ABI, HDL, creatinine, LDL, VPT	Age, duration of diabetes, skin autofluorescence, BUN, creatinine, triglyceride, HDL, LDL, C‐reactive protein, left ABI, right ABI, VPT
Hu et al (2014) ³⁷	Any DF (FU, FG, LEA)	risk factors associated with FU, FG and/or LEA: nationality (non‐Saudi vs Saudi: OR 2.47 [95% CI 1.39‐4.38], P = .002), PN (3.21 [1.69‐6.10], P < .0001), PVD (2.80 [1.56‐5.01], P < .001), duration of diabetes (10.1‐20 y vs < 5 y: 3.70 [1.26‐10.84]; >20 y vs < 5 y: 3.60 [1.09‐11.89]); not stat. sign.: gender, age, inulin use, OHA use, clopidogrel use, duration of diabetes (5‐10 y vs < 5 y), haemoglobin (125‐138 g/l, 138‐149 g/l, ≥149 g/l, all vs < 125 g/l)	Multivariate logistic regression model adjusted for: age, gender, nationality, insulin use, OHA use, clopidogrel use, duration of diabetes, haemoglobin, PN, PVD
Humphrey et al (1996) ³⁸	LEA	stat. sign.: fasting plasma glucose (per 1mmol/l increment: RR 1.26 [95% CI 1.14‐1.38], P < .001), diabetes duration (per year increase: 1.15 [1.07‐1.23], P < .001), female gender (0.34 [0.18‐0.83], P = .015), systolic blood pressure (per 10 mmHg: 0.78 [0.76‐0.80], P = .010); not stat. sign.: age, BMI, total plasma cholesterol, fasting plasma triglycerides, mean daily alcohol intake, smoking	Age, gender, duration of diabetes, mean daily alcohol intake, smoking, BMI, systolic blood pressure, total plasma cholesterol, fasting plasma triglycerides, fasting plasma glucose
Jiang et al (2015) ³⁹	FU	Risk factors associated with FU at baseline: stat. sign.: male gender (OR 2.062 [95% CI 1.323‐3.215], P = .001), smoking (1.597 [1.057‐2.411], P = .026), location (city vs rural: 2.234 [1.515‐3.293], P < .0001), retinopathy (1.781 [1.234‐2.569], P = .002), ABI < 0.9 (5.452 [3.489‐8.519], P < .0001), intermittent claudication (5.216 [2.763‐9.848), P < .0001), diabetes therapy (insulin vs OHA: 4.205 [2.247‐7.869], P < .0001; OHA and insulin vs OHA: 2.526 [1.323‐4.824], P = .005), BMI (0.927 [0.883‐0.927], P = .002), HDL (per unit increase: 0.238 [0.134‐0.423], P < .0001), haemoglobin (per unit increase: 0.976 [0.970‐0.985], P < .0001), postprandial blood glucose (0.940 [0.908‐0.972], P < .0001); not stat. sign.: age, living alone (yes/no), occupation, hypertension, PN, PVD, nephropathy, cataracts, duration of diabetes, HbA1c, fasting plasma glucose, bilirubin, creatinine, cholesterol, triglyceride, albumin, WBC Risk factors associated with FU at follow‐up: stat. sign.: HDL (OR 0.427 [95% CI 0.228‐0.799], P = .008), nephropathy (2.320 [1.449‐3.714], P < .0001), diabetes therapy (insulin vs OHA: 3.136 [1.357‐7.251], P = .008; OHA and insulin vs OHA: 2.629 [1.125‐6.148], P = .026); not stat. sign.: all other factors also analysed at baseline	Age, gender, location, living alone, occupation, smoking, hypertension, PN, PVD, nephropathy, retinopathy, cataracts, duration of diabetes, diabetes therapy, ABI, intermittent claudication, BMI, HbA1c, fasting plasma glucose, postprandial blood glucose, bilirubin, creatinine, cholesterol, triglyceride, HDL, haemoglobin, albumin, WBC
Kästenbauer et al (2001) ⁴⁰	FU	stat. sign.: elevated VPT (RR 25.4 [95% CI 3.1‐205], P = .0024), mean plantar pressure (6.3 [1.2‐32.7], P = .0291), daily alcohol intake (5.1 [1.1‐24.0], P = .0404), mediasclerosis (0.07 [0.01‐0.6], P = .0174); not stat. sign.: age, diabetes duration, body weight, OHA therapy, insulin use, history of angiography, flatfoot deformity, hallux valgus, oxford shoes, varicosis, dry skin, skeletal abnormalities, HbA1c, triglycerides, stage of peroneal nerve conduction velocity, diastolic blood pressure	Age, elevated VPT, elevated mean plantar pressure, diabetes duration, body weight, OHA therapy, insulin use, history of angiography, daily alcohol intake, flatfoot deformity, hallux valgus, oxford shoes, varicosis, dry skin, mediasclerosis, skeletal abnormalities, HbA1c, triglycerides, stage of peroneal nerve conduction velocity, diastolic blood pressure
Lai et al (2015) ⁴¹	LEA	stat. sign.: age at T2DM onset (HR 1.024 [95% CI 1.013‐1.035]), male gender (1.643 [1.237‐2.183]), heart failure (2.134 [1.445‐3.151]), hypertension (0.674 [0.496‐0.915]), coronary artery disease (0.705 [0.502‐0.988]), hyperlipidaemia (0.361 [0.269‐0.486]), retinopathy (2.067 [1.118‐3.821]), PN (2.338 [1.617‐3.38]), peripheral arterial occlusive disease (4.134 [2.717‐6.289]); not stat. sign.: chronic kidney disease, atrial fibrillation, stroke, nephropathy	Age, gender, heart failure, chronic kidney disease, hypertension, coronary artery disease, hyperlipidaemia, atrial fibrillation, stroke, nephropathy, retinopathy, PN, peripheral arterial occlusive disease
Robinson et al (2016) ⁴²	LEA	stat. sign.: ethnicity (East Asian vs European/other: HR 0.23 [95% CI 0.10‐0.56], P < .001; Indian vs European/other: 0.48 [0.27‐0.83], P < .001; Maori vs European/other: 1.61 [1.35‐1.93], P < .001), age at onset (per 10 y: 1.52 [1.42‐1.63], P < .001), female gender (0.72 [0.60‐0.87], P < .001), diabetes duration (per year: 1.19 [1.17‐1.22], P < .001), smoking status (ex‐smoker vs nonsmoker: 1.26 [1.09‐1.47], P = .003; current smoker vs nonsmoker: 1.63 [1.35‐1.97], P < .001), height (per 10 cm: 1.35 [1.23‐1.48], P < .001), systolic BP (per 10 mmHg: 0.69 [0.53‐0.89], P = .005; squared: 1.01 [1.01‐1.02], P = .001), HbA1c (per 10 mmol/mol: 1.27 [1.24‐1.31], P < .001), total/HDL‐cholesterol ratio (1.05 [1.02‐1.09], P = .007); not stat. sign.: ethnicity (Pacific vs European/other), weight, BMI	Age, gender, ethnicity, diabetes duration, smoking status, height, systolic BP, HbA1c, total/HDL‐cholesterol ratio, weight, BMI
Sarfo‐Kantanka et al (2019) ⁴³	LEA	stat. sign.: age (per 10‐year increase: HR 1.11 [95% CI 1.06‐1.22], P < .001), male gender (3.50 [2.88‐5.23], P < .001), type of diabetes (T2DM vs T1DM: 8.21 [2.58‐1.07], P < .001), BMI (each 5kg/m ² increase: 3.2 [2.51‐7.25], P < .001), HbA1c (per % increase: 1.11 [1.05‐1.25], P = .03), hypertension (1.14 [1.12‐3.21], P < .001), PN (6.56 [6.21‐8.52], P < .001), PVD (7.73 [4.39‐9.53], P < .001); not stat. sign.: duration of diabetes, dyslipidaemia, nephropathy	Variables included in the model were as follows: age, gender, duration of diabetes, type of diabetes, BMI, glycaemic control (HbA1c), lipid status, hypertension, renal function, PN, PVD
Selby et al (1995) ⁴⁴	LEA	stat. sign.: glucose score (OR 1.75 [1.37‐2.24]), systolic blood pressure (per 1 mm Hg: 1.02 [1.01‐1.04]), retinopathy (3.68 [1.78‐7.62]), PN (4.05 [2.01‐8.17]), stroke (2.70 [1.27‐5.75]); not stat. sign.: duration of diabetes, type of diabetes, BMI, treatment (insulin and OHA, both vs diet only), ethnicity (black and other, both vs white), total cholesterol, smoking status (never or ex‐smoker vs current smoker), myocardial infarction	Age, gender, glucose score, duration of diabetes, type of diabetes, BMI, treatment, ethnicity, systolic blood pressure, total cholesterol, smoking, retinopathy, PN, stroke, myocardial infarction
Sheen et al (2018) ⁴⁵	LEA	stat. sign.: age (5 age groups [35‐45, 45‐55, 55‐65, 65‐75, >75 y] compared to < 35 y: each HR ≥ 1.73, each P < .0001), male gender (HR 1.83 [95% CI 1.756‐1.916], P < .0001), salary (8 salary groups [insured dependents, ≤15,840; 15,841‐22,800; 22,801‐28,800; 28,801‐36,300; 36,301‐45,800; 45,801‐57,800; 57,801‐72,800] compared to > 72,801: each HR ≥ 4.67, each P < .0009), low income status (3.69 [3.387‐4.028), P < .0001), diabetic complications (different number of complications [1, 2, 3, 4, ≥5] compared to no complications: each HR ≥ 1.68, each P < .0001, city household income (middle vs high: 1.12 [1.066‐1.178], P < .0001), degree of urbanization (urbanization divided into 8 levels; all levels compared with highest level of urbanization: each HR ≥ 1.26; each P < .0001), attending clinic for regular care is not a metabolic disease clinic (1.47 [1.362‐1.591], P < .0001), ownership of hospital for regular care (nonprofit vs public: 1.16 [1.085‐1.248], P < .0001), not attending preventive programme ‘P4P Care’ (3.46 [3.187‐3.758], P < .0001); not stat. sign.: household income (low vs high), ownership of hospital for regular care (private vs public)	Age, gender, salary, income status, number of diabetic complications, city household income, degree of urbanization, metabolic disease clinic (for patient's regular care), ownership of hospital (for patient's regular care), attendance of preventive programme ‘P4P Care’
Tseng et al (2006) ⁴⁶	LEA	stat. sign.: age (10‐year increment: OR 1.19 [95% CI 1.10‐1.28], P < .01), type of diabetes (1.67 [1.24‐2.25), P < .01), duration of diabetes (10‐year increment: 1.78 [1.65‐1.93], P < .01), smoking status (ex‐smoker vs never smoker: 1.33[1.05‐1.69], P < .05), hypertension (1.34 [1.15‐1.57], P < .01), body height (10‐cm increment: 1.16 [1.03‐1.32], P < .05); stat. sign. risk factors studied in subset of 9,295 subjects: fasting plasma glucose (0.6 mmol/l increment: 1.12 [1.04‐1.21], P < .01); not stat. sign.: gender, smoking status (current vs never smoked), dyslipidaemia (yes vs no; and unknown vs no)	Age, gender, duration of diabetes, type of diabetes, smoking, hypertension, height, fasting plasma glucose, dyslipidaemia
Tuttolomondo et al (2017) ⁴⁷	FU	stat. sign.: hypertension (OR 21.27 [95% CI 4.09‐110.62], P = .0001), dyslipidaemia (6.07 [1.43‐25.66], P = .014), BMI (1.17 [1.02‐1.34], P = .019), pulse wave velocity (2.26 [1.36‐3.75], P = .002), reactive hyperaemia index (0.01 [0.001‐0.185], P = .002); not stat. sign.: age, systolic blood pressure, aortic augmentation index, cognitive function (Mini‐Mental State Examination)	Age, hypertension, dyslipidaemia, BMI, systolic blood pressure, arterial stiffness (aortic augmentation index, pulse wave velocity), endothelial function (reactive hyperaemia index), cognitive function (Mini‐Mental State Examination)
Venermo et al (2013) ⁴⁸	LEA	stat. sign.: age (4 age groups [50‐64, 65‐74, 75‐84, >85 y] all compared to 30‐39 y: each HR ≥ 3.07, each P < .0001), socio‐economic position (4 quintiles [2nd, 3rd, 4th and 5th = highest quintile] compared with 1 = lowest quintile: each HR ≤ 0.89; each P < .001), female gender (HR 0.62 [95% CI 0.59‐0.65], P < .001), type of diabetes (T2DM vs T1DM: 0.57 [0.54‐0.61], P < .001), diabetes duration (10‐19 y vs 0‐9 y: 2.50 [2.36‐2.64], P < .001; ≥20 y vs 0‐9 y: 3.30 [3.09‐3.52], P < .001), amputation year (per year from 1987 to 2007:0.93 [0.92‐0.93], P < .001)	Age, gender, socio‐economic position, diabetes type, duration of diabetes, year of amputation
Williams et al (2010) ⁴⁹	FU	stat. sign.: major depression compared to no depression (HR 2.00 [95% CI 1.24‐3.25]); not stat. sign.: minor depression compared to no depression	Age, gender, ethnicity, education, marital status, diabetes duration, insulin use, number of diabetes complications, BMI, smoking status, foot self‐care, HbA1c
Yang et al (2011) ⁵⁰	LEA	stat. sign.: age ≥ 65 (OR 0.8 [95% CI 0.71‐0.89], P < .001), female gender (0.79 [0.71‐0.87], P < .001), year of discharge (2007 vs 2004:0.72 [0.60‐0.87], P = .001; 2008 vs 2004:0.58 [0.48‐0.70], P < .001; 2009 vs 2004:0.40 [0.34‐0.49], P < .001), ethnicity (Malay vs Chinese: 1.55 [1.35‐1.77], P < .001), renal disease (3.18 [2.84‐3.56], P < .001); not stat. sign.: year of discharge (2005 vs 2004; 2006 vs 2004), ethnicity (India vs Chinese; Other vs Chinese)	Age, gender, ethnicity, year of discharge, nephropathy
Ye et al (2014) ⁵¹	FU	stat. sign. in female patients: uric acid (for every 1‐μmol/L increment: OR 1.004 [95% CI 1.001‐1.008], P < .05; quintile 5 vs quintile 1:4.727 [1.357‐16.468], P < .05); not stat. sign.: uric acid (quintiles 2, 3, 4, each vs quintile 1 [lowest concentration of uric acid])	Age, duration of diabetes, uric acid, PVD, PN
Young et al (2003) ⁵²	LEA	stat. sign.: ethnicity (African American vs White: RR 1.41 [95% CI 1.34‐1.48], Hispanic vs White: 1.28 [1.20‐1.38], Native American vs White: 1.74 [1.39‐2.18], Asian vs White: 0.31 [0.19‐0.50]), nephropathy (3.41 [3.13‐3.71]), diabetic end‐stage renal disease (3.77 [3.57‐3.99])	Age, gender, ethnicity, CVD, hypertension, COPD, service connection, region, stroke, nephropathy, diabetic end‐stage renal disease
Younis et al (2018) ⁵³	FU	stat. sign.: age (OR 1.027 [95% CI 1.003‐1.051], P = .025), duration of diabetes (1.063 [1.027‐1.100], P = .001), PN (23.926 [5.41‐105.6], P = .001), PVD (0.267 [0.143‐0.532], P = .001), HbA1c (6.187 [4.646‐8.239], P = .001); not stat. sign.: gender, BMI	Age, gender, duration of diabetes, BMI, HbA1c, PN, PVD
Zhao et al (2016) ⁵⁴	FU	stat. sign.: serum cystatin C (OR 4.828 [95% CI 1.711‐13.620], P = .003), coronary artery disease (3.566 [1.470‐8.648], P = .005), insulin use (2.605 [1.258‐5.394], P = .01), difference between supine and sitting transcutaneous oxygen pressure (1.076 [1.032‐1.122], P = .001), hypertension (1.021 [1.003‐1.039], P = .023); not stat. sign.: age, diastolic blood pressure, haemoglobin, creatinine, calcium, albumin, triglycerides, HDL, proteinuria, microalbuminuria, ABI, transcutaneous oxygen pressure (in sitting position, in supine position)	Age, gender, duration of diabetes, smoking, insulin use, hypertension, coronary artery disease, diastolic blood pressure, haemoglobin, potassium, proteinuria, microalbuminuria, ABI, transcutaneous oxygen pressure (in sitting position, supine position and difference between supine and sitting position)

Abbreviations: ABI, ankle‐brachial index; ALT, alanine transaminase; AST, aspartate transaminase; BMI, body mass index; BP, blood pressure; BUN, blood urea nitrogen; CA, Charcot arthropathy; CI, confidence interval; COPD, chronic obstructive pulmonary disease; CVD, cardiovascular disease; DF, diabetic foot; ECG, electrocardiogram; eGFR, estimated glomerular filtration rate; FG, foot gangrene; FU, foot ulceration; GGT, gamma‐glutamyl transferase; GP, general practitioner; HbA1c, haemoglobin A1c; HDL, high‐density lipoprotein; HR, hazard ratio, LDL, low‐density lipoprotein; LEA, lower extremity amputation; mmHg, millimetres of mercury; OHA, oral hypoglycaemic agent; OR, odds ratio, PlGF, placenta growth factor; PN, peripheral neuropathy; PVD, peripheral vascular disease; RR, risk ratio; stat. sign., statistically significant; T1DM, type 1 diabetes mellitus; T2DM, type 2 diabetes mellitus; VEGF‐A, vascular endothelial growth factor A; VPT, vibration perception threshold; WBC, white blood cell count.