We investigated the ability of time-warping-based ECG-derived markers of T-wave morphology changes in time ($$d_{w}$$
d
w
) and amplitude ($$d_a$$
d
a
), as well as their non-linear components ($${d_w^{{\mathrm{NL}}}}$$
d
w
NL
and $${d_a^{\mathrm{NL}}}$$
d
a
NL
), and the heart rate corrected counterpart ($$d_{w,c}$$
d
w
,
c
), to monitor potassium concentration ($$[K^{+}]$$
[
K
+
]
) changes ($$\Delta [K^+]$$
Δ
[
K
+
]
) in end-stage renal disease (ESRD) patients undergoing hemodialysis (HD). We compared the performance of the proposed time-warping markers, together with other previously proposed $$[K^{+}]$$
[
K
+
]
markers, such as T-wave width ($$T_w$$
T
w
) and T-wave slope-to-amplitude ratio ($$T_{S/A}$$
T
S
/
A
), when computed from standard ECG leads as well as from principal component analysis (PCA)-based leads. 48-hour ECG recordings and a set of hourly-collected blood samples from 29 ESRD-HD patients were acquired. Values of $$d_w$$
d
w
, $$d_a$$
d
a
, $${d_w^{\mathrm{NL}}}$$
d
w
NL
, $${d_a^{\mathrm{NL}}}$$
d
a
NL
and $$d_{w,c}$$
d
w
,
c
were calculated by comparing the morphology of the mean warped T-waves (MWTWs) derived at each hour along the HD with that from a reference MWTW, measured at the end of the HD. From the same MWTWs $$T_w$$
T
w
and $$T_{S/A}$$
T
S
/
A
were also extracted. Similarly, $$\Delta [K^+]$$
Δ
[
K
+
]
was calculated as the difference between the $$[K^{+}]$$
[
K
+
]
values at each hour and the $$[K^{+}]$$
[
K
+
]
reference level at the end of the HD session. We found that $$d_{w}$$
d
w
and $$d_{w,c}$$
d
w
,
c
showed higher correlation coefficients with $$\Delta [K^+]$$
Δ
[
K
+
]
than $$T_{S/A}$$
T
S
/
A
—Spearman’s ($$\rho$$
ρ
) and Pearson’s (r)—and $$T_w$$
T
w
—Spearman’s ($$\rho$$
ρ
)—in both SL and PCA approaches being the intra-patient median $$\rho \ge 0.82$$
ρ
≥
0.82
and $$r \ge 0.87$$
r
≥
0.87
in SL and $$\rho \ge 0.82$$
ρ
≥
0.82
and $$r \ge 0.89$$
r
≥
0.89
in PCA respectively. Our findings would point at $$d_{w}$$
d
w
and $$d_{w,c}$$
d
w
,
c
as the most suitable surrogate of $$\Delta [K^+]$$
Δ
[
K
+
]
, suggesting that they could be potentially useful for non-invasive monitoring of ESRD-HD patients in hospital, as well as in ambulatory settings. Therefore, the tracking of T-wave morphology variations by means of time-warping analysis could improve continuous and remote $$[K^{+}]$$
[
K
+
]
monitoring of ESRD-HD patients and flagging risk of $$[K^{+}]$$
[
K
+
]
-related cardiovascular events.