Table 2 Outcomes, Results, Risk of Bias of Included Studies and Level of Evidence per Outcome according to GRADE Criteria

 Brenyo et al. [45], 2012.

6MWT

4 years

Incident HF and Mortality

≤ 350 m VS > 350 m

HR = 1.73 95%CI [1.29–2.33]***

Low

Not

Reported

Incident HF and Mortality

Per 100-m decreased

HR = 1.25 95%CI [1.09–1.44]***

All-Cause Mortality

≤ 350 m VS > 350 m

HR = 2.40 95%CI [1.42–4.08]***

Moderate

All-Cause Mortality

Per 100-m decreased

HR = 1.32 95%CI [1.05–1.66]**

 Ferreira et al. [46], 2019.

6MWT

21 months (9–26 months)

Hospitalisation and Mortality

241-360 m VS > 360 m

HR = 1.44 95%CI [1.14–1.80]**

Moderate

Low

Hospitalisation and Mortality

≤ 240 m VS > 360 m

HR = 1.73 95%CI [1.38–2.18]***

Hospitalisation and Mortality

Per each 50 m decreased

HR = 1.08 95%CI [1.04–1.11]***

All-Cause Mortality

241-360 m VS > 360 m

HR = 1.49 95%CI [1.08–2.06]**

Moderate

All-Cause Mortality

≤ 240 m VS > 360 m

HR = 2.41 95%CI [1.76–3.29]***

All-Cause Mortality

Per each 50 m decreased

HR = 1.14 95%CI [1.09–1.18]***

 Wegrzynowska-Teodorczyk et al. [47], 2013.

6MWT

1 year

HF Mortality

≤ 468 m VS > 468 m

HR = 3.22 95%CI [1.17–8.86]**

Low

Moderate

Hospitalisation and Mortality

≤ 468 m VS > 468 m

HR = 2.77 95%CI [1.30–5.88]**

Low

3 years

HF Mortality

≤ 468 m VS > 468 m

HR = 2.18 95%CI [1.18–4.03]**

Moderate

Hospitalisation and Mortality

≤ 468 m VS > 468 m

HR = 1.71 95%CI [1.08–2.72]**

Low

 Bittner et al. [48], 1993.

6MWT

1 year (242 ± 82 days)

All-Cause Mortality

Per each 120 m decreased

OR = 1.50 95%CI [1.11–2.03]**

Low

Moderate

HF Hospitalisation

Per each 120 m decreased

OR = 2.60 95%CI [1.78–3.80]***

Low

Hospitalisation and Mortality

Per each 120 m decreased

OR = 1.77 95%CI [1.38–2.26]***

Low

All-Cause Mortality

<  300 m VS ≥ 450 m

OR = 3.7 95%CI [1.44–9.55]**

Moderate

All-Cause Mortality

300-375 m VS ≥ 450 m

OR = 2.78 95%CI [1.09–7.11]**

All-Cause Mortality

375-450 m VS ≥ 450 m

OR = 1.42 95%CI [0.50–4.06]*

All-Cause Hospitalisation

<  300 m VS ≥ 450 m

OR = 14.02 95%CI [4.90–40.14]***

Low

All-Cause Hospitalisation

300-375 m VS ≥ 450 m

OR = 6.21 95%CI [2.14–18.08]***

All-Cause Hospitalisation

375-450 m VS ≥ 450 m

OR = 1.90 95%CI [0.56–6.42]*

 Arslan et al. [49], 2007.

6MWT

2 years (18 ± 6 months)

HF Mortality

≤ 300 m VS >  300 m

HR = 2.38 95%CI [2.02–5.76]**

Moderate

Moderate

 Lee et al. [50], 2006.

6MWT

36 ± 12 months

Hospitalisation and Mortality

75-230 m VS > 370 m.

OR = 3.5 95%CI [1.1–11.7]**

Low

Low

Hospitalisation and Mortality

231-310 m VS > 370 m

OR = 3.4 95%CI [1.01–11.5]**

Hospitalisation and Mortality

311-370 m VS > 370 m

OR = 4.9 95%CI [1.5–16.0]**

 Curtis et al. [51], 2004.

6MWT

32 months

All-Cause Mortality

≤ 200 m VS > 400 m

HR = 1.59 95%CI [0.88–2.86]*

Low

Moderate

All-Cause Mortality

201-300 m VS > 400 m

HR = 1.01 95%CI [0.57–1.79]*

All-Cause Mortality

301-400 m VS > 400 m

HR = 1.16 95%CI [0.72–1.88]*

HF Mortality

≤ 200 m VS > 400 m

HR = 2.62 95%CI [1.02–6.74]**

Moderate

HF Mortality

201-300 m VS > 400 m

HR = 0.93 95%CI [0.34–2.55]*

HF Mortality

301-400 m VS > 400 m

HR = 0.86 95%CI [0.35–2.09]*

All-Cause Hospitalisation

≤ 200 m VS > 400 m

HR = 1.76 95%CI [1.19–2.60]**

Low

All-Cause Hospitalisation

201-300 m VS > 400 m

HR = 1.41 95%CI [1.01–1.99]**

All-Cause Hospitalisation

301-400 m VS > 400 m

HR = 1.09 95%CI [0.80–1.47]*

HF Hospitalisation

≤ 200 m VS > 400 m

HR = 1.84 95%CI [0.97–3.49]*

Low

HF Hospitalisation

201-300 m VS > 400 m

HR = 1.84 95%CI [1.04–3.29]**

HF Hospitalisation

301-400 m VS > 400 m

HR = 1.45 95%CI [0.85–2.45]*

 Ingle et al. [52], 2014.

6MWT

5 years

All-Cause Mortality

Per each 10 m increased.

HR = 0.980 95%CI [0.974–0.985]***

Low

Moderate

 Alahdab et al. [53], 2009.

6MWT

40 months-Mortality

All-Cause Mortality

≤ 200 m VS >  200 m

HR = 2.14 95%CI [1.20–3.81]**

Low

Moderate

40 months-Mortality

All-Cause Mortality

Per each 1 m increased

HR = 0.998 95%CI [0.995–0.999]**

18 months-Hospitali- zation

HF Hospitalisation

≤ 200 m VS >  200 m

HR = 1.62 95%CI [1.10–2.39]**

Low

 Mangla et al. [54], 2013.

6MWT

1080 days

Hospitalisation and Mortality

≤ 189 m VS > 189 m

in HFpEF.

OR = 2.81 95%CI [1.24–6.40]**

Low

Low

Hospitalisation and Mortality

≤ 189 m VS > 189 m in HFrEF.

OR = 1.94 95%CI [1.30–2.90]**

 Hasin et al. [55], 2012.

6MWT

Median 592 days (115–1453 days)

All-Cause Mortality

Per 10 m walked short of 300 m

HR = 1.211 95% CI [1.108–1.322]***

Moderate

Moderate

 Passantino et al. [56], 2006.

6MWT

23.9 months

All-Cause Mortality

<  300 m VS ≥ 300 m

HR = 2.66 95%CI [1.60–4.42]***

Low

Moderate

All-Cause Mortality

Per each 70 m decreased

HR = 2.03 95%CI [1.29–3.18]**

Howie-Esquivel et al. [57], 2008.

6MWT

90 days

HF Hospitalisation

> 200 m

HR = 0.99 95%CI [0.99–1.00]*

High

Low

 Zotter-Tufaro et al. [58], 2015.

6MWT

14.0 ± 10.0 months

Hospitalisation and Mortality

>  300 m VS ≤ 300 m

HR = 0.992 95%CI [0.990–0.995]***

Moderate

Low

 Boxer et al. [59], 2010.

6MWT

4 years

All-Cause Mortality

Per each 30 m increased

HR = 0.84 95%CI [0.74–0.94]**

Moderate

Moderate

 Ingle et al. [60], 2014.

6MWT

8 years

All-Cause Mortality

Per each 10 m increased

HR = 0.988 95%CI [0.981–0.995]***

Low

Moderate

 Guazzi et al. [61], 2009.

6MWT

20.4 ± 16.6 months.

Cardiac Mortality

Per each 1 m increased

HR = 0.998 95%CI [0.995–1.001]*

Low

Moderate

 McCabe et al. [62], 2017.

6MWT

30 days

HF Hospitalisation

Per each 30 m increased

OR = 0.84 95% CI [0.71–0.99]**

Moderate

Low

 Vegh et al. [63], 2014.

6MWT

3 years

HF Hospitalisation

≥ 350 m VS < 280 m

HR = 0.61 95% CI [0.44–0.85]**

Moderate

Low

Hospitalisation and Mortality

≥ 350 m VS < 280 m

HR = 0.58 95% CI [0.43–0.80]***

Low

HF Hospitalisation

≥ 402 m VS < 256 m

HR = 0.60 95% CI [0.44–0.82]***

Low

Hospitalisation and Mortality

≥ 402 m VS < 256 m

HR = 0.55 95% CI [0.43–0.75]***

Low

 Roul et al. [64], 1998.

6MWT

1000 days

Hospitalisation and Mortality

≤ 300 m VS > 300 m

Log rank = 6.16 **

Moderate

Low

 Frankenstein et al. [65], 2008.

6MWT

52.9 ± 36.2 months

All-Cause Mortality

Per each 1 m increased

HR = 0.996 95% CI [0.995–0.997]***

Low

Moderate

 Mene-Afejuku et al. [66], 2017.

6MWT

6 months

Hospitalisation and Mortality

314.66 m ± 48.17 m VS 260.59 m ± 66.65 m

OR = 0.819 95% CI [0.206–3.257]*

Moderate

Low

 Ingle et al. [67], 2007.

6MWT

36.6 months

(28.2–45.0 months)

All-Cause Mortality

Per each 1 m increased

HR = 0.998 95% CI [0.996–1.000]*

Low

Moderate

 Rostagno et al. [68], 2003.

6MWT

34 months

All-Cause Mortality

Per each 1 m increased

HR = 0.995 95% CI [0.993–0.997]***

Low

Moderate

 Cahalin et al. [69], 1996.

6MWT

62 ± 45 weeks (1–183 weeks)

Hospitalisation and Mortality

<  300 m VS ≥ 300 m

X² = 40% vs 12% **

Moderate

Low

 Frankenstein et al. [70], 2008.

6MWT

42 months (22–80 months)

All-Cause Mortality

Per each 1 m increased

HR = 0.996 95% CI [0.995–0.997]**

Moderate

Moderate

 Rubim et al. [71], 2006.

6MWT

18 months (12–24 months)

All-Cause Mortality

≥ 520 m VS < 520 m

OR = −0.0081 95% CI [0.0029–0.0133]***

Low

Moderate

 Kanagala et al. [72], 2019.

6MWT

1429 days (1157–1657 days)

Hospitalisation and Mortality

Per each 1 m increased

HR = 0.659 95% CI [0.465–0.934]**

Low

Low

 Zugck et al. [73], 2001.

6MWT

28.3 ± 14.1 months

All-Cause Mortality

Per each 1 m increased

HR = 0.99 95% CI [0.98–0.99]**

Moderate

Moderate

 Cahalin et al. [74], 2013.

6MWT

22.8 ± 22.1 months

Cardiac Mortality

Per each 1 m increased

HR = 0.99 95% CI [0.99–0.99]**

Low

Moderate

Cardiac Mortality

>  300 m VS ≤ 300 m

HR = 0.18 95% CI [0.04–0.89]**

 Reibis et al. [75], 2010.

6MWT

731 ± 215 days

All-Cause Mortality

Per each 50 m increasd

HR = 0.93 95% CI [0.86–1.00]**

Low

Moderate

 Castel et al. [76], 2009.

6MWT

24.4 ± 18.1 months

Cardiac Mortality

<  225 m VS > 400 m

HR = 5.60 95% CI [1.23–25.30]**

Low

Moderate

Cardiac Mortality

225-310 m VS > 400 m

HR = 1.28 95% CI [0.23–7.08]*

Cardiac Mortality

310-400 m VS > 400 m

HR = 4.10 95% CI [0.79–21.52]*

 Kamiya et al. [77], 2017.

6MWT

2.3 ± 1.9 years

All-Cause Mortality

Per each 10 m increased

HR = 0.96 95% CI [0.94–0.97]***

Low

Moderate

 García et al. [78], 2019.

SPPB

1 year

HF Hospitalisation

SPPB ≤ 7 VS SPPB > 7

OR = 6.7 95%CI [1.5–30.4]**

Moderate

Not Reported

All-Cause Mortality

SPPB ≤ 7 VS SPPB > 7

OR = 1.2 95%CI [0.3–5.4]*

Very Low

Hospitalisation and Mortality

SPPB ≤ 7 VS SPPB > 7

OR = 3.6 95%CI [1.0–12.9]**

Very Low

 Hornsby et al. [79], 2019.

SPPB

6 months

Hospitalisation and Mortality

Per 1-unit change in SPPB

OR = 0.81 95%CI [0.69–0.94]**

Moderate

Very Low

Number of All-Cause Hospitalisations

Per 1-unit change in SPPB

IRR = 0.92 95%CI [0.86–0.97]**

Not Reported

Days Hospitalized or Dead

Per 1-unit change in SPPB

IRR = 0.85 95%CI [0.73–0.99]**

Not Reported

 Chiarantini et al. [80], 2010.

SPPB

30 months (median 444 days)

All-Cause Mortality

SPPB 0 VS SPPB 9–12

HR = 6.06 95%CI [2.19–16.76]***

Moderate

Very Low

All-Cause Mortality

SPPB 1–4 VS SPPB 9–12

HR = 4.78 95%CI [1.63–14.02]**

All-Cause Mortality

SPPB 5–8 VS SPPB 9–12

HR = 1.95 95%CI [0.67–5.70]*

 Zaharias et al. [81], 2014.

SPPB

3 months

Hospitalisation and Mortality

Per each 1 point decreased

HR = 1.042 95%CI [0.89–1.23]*

Moderate

Very Low

 Lo et al. [82], 2015.

Gait Speed

10 years

All-Cause Mortality

< 0.8 m/s VS ≥ 0.8 m/s

HR = 1.37 95%CI [1.10–1.70]**

Low

Low

 Pulignano et al. [83], 2016.

Gait Speed

1 year

All-Cause Mortality

Gait speed (tertiles)

HR = 0.620 95%CI [0.434–0.884]**

Low

Low

HF Hospitalisation

Gait speed (tertiles)

OR = 0.697 95%CI [0.547–0.899]**

Low

All-Cause Hospitalisation

Gait speed (tertiles)

HR = 0.741 95%CI [0.613–0.895]**

Low

 Chaudhry et al. [84], 2013.

Gait Speed

20 years

All-Cause Hospitalisation

≤ 0.8 m/s VS > 0.8 m/s

HR = 1.28 95%CI [1.06–1.55]**

Low

Low

Hospitalisation and Mortality

≤ 0.8 m/s VS > 0.8 m/s

HR = 1.31 95%CI [1.08–1.58]**

Low

 Tanaka et al. [85], 2018.

Gait Speed

1.7 ± 0.5 years

All-Cause Mortality

1.0–1.14 m/s VS > 1.14 m/s

HR = 0.80 95%CI [0.37–1.74]*

Moderate

Low

All-Cause Mortality

0.82–0.99 m/s VS > 1.14 m/s

HR = 1.46 95%CI [0.75–2.83]*

All-Cause Mortality

< 0.82 m/s VS > 1.14 m/s

HR = 2.65 95%CI [1.35–5.20]**

 Tanaka et al. [86], 2019.

Gait Speed

2.1 ± 1.9 years

All-Cause Mortality

Per each 0.1 m/s increased

HR = 0.83 95% CI [0.73–0.95]**

Low

Low

HF Hospitalisation

Per each 0.1 m/s increased

HR = 0.91 95% CI [0.83–0.99]**

Low

Hospitalisation and Mortality

Per each 0.1 m/s increased

HR = 0.90 95% CI [0.83–0.97]**

Low

 Rodríguez-Pascual et al. [87], 2017.

Gait Speed

1 year

All-Cause Mortality

GS < 0.65 m/s VS GS ≥ 0.65 m/s

HR = 1.86 95% CI [0.95–3.65]*

Low

Low

All-Cause Hospitalisation

GS < 0.65 m/s VS GS ≥ 0.65 m/s

HR = 1.57 95% CI [0.98–2.52]*

Low

 Vidán et al. [88], 2016.

Gait Speed

1 year

All-Cause Mortality

GS < 0.65 m/s VS GS ≥ 0.65 m/s

HR = 1.48 95% CI [0.95–2.32]*

Low

Low

All-Cause Hospitalisation

GS < 0.65 m/s VS GS ≥ 0.65 m/s

OR = 1.67 95% CI [0.98–2.85]*

Low

 Kamiya et al. [77], 2017.

Gait Speed

2.3 ± 1.9 years

All-Cause Mortality

Per each 0.1 m/s increased

HR = 0.87 95% CI [0.81–0.93]***

Low

Low