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. 2024 Sep 10;26:e58187. doi: 10.2196/58187

Table 12.

Pooled mean estimates of correlation coefficient (r) in detecting the severity of sleep apnea by several factors.

Groups Studies, n (%) Sample size, N Correlation coefficient (%), range Pooled mean correlation coefficient (%; 95% CI) Heterogeneity measures Test for subgroup differences, P value





Tau2 Q (P value) I² (%)
Type of algorithm .12

Machine learning 3 (8) 526 0.90 to 0.96 0.922 (0.66 to0.98) 0.0987 25.6 (<.01) 92

Deep learning 9 (24) 740 0.64 to 0.91 0.856 (0.79 to0.90) 0.0552 53.1 (<.01) 85
Sample size, n .79

≤100 9 (24) 541 0.64 to 0.90 0.879 (0.85 to0.90) 0.0001 12.7 (.12) 37

>100 3 (8) 725 0.71 to 0.96 0.896 (0.12 to0.99) 0.2849 173.0 (<.01) 99
Type of sleep apnea .54

All 8 (21) 802 0.64 to 0.96 0.886 (0.81 to0.93) 0.0918 80.2 (<.01) 91

Obstructive sleep apnea 4 (11) 464 0.71 to 0.90 0.859 (0.68 to0.94) 0.759 34.7 (<.01) 91
Status of the WDa .35

Commercial 10 (26) 1177 0.64 to 0.96 0.881 (0.82 to 0.92) 0.0977 191.1 (<.01) 95

Noncommercial 2 (5) 89 0.84 to 0.86 0.856 (0.72 to 0.93) 0.0000 0.1 (.79) 0
Placement of the WD <.001 b

Wrist 2 (5) 316 0.71 to 0.91 0.833 (–0.99 to 1.00) 0.1948 20.1 (<.01) 95

Chest 2 (5) 452 0.87 to 0.96 0.929 (–0.98 to 1.00) 0.1765 16.7 (<.01) 94

Finger 3 (8) 212 0.89 to 0.90 0.894 (0.88 to0.91) 0.0000 0.1 (.93) 0

Neck 2 (5) 89 0.84 to 0.86 0.856 (0.72 to0.93) 0.0000 0.1 (.79) 0

Abdomen 2 (5) 158 0.89 to 0.90 0.894 (0.81 to 0.94) 0.0000 0.1 (.76) 0
Data type <.001

Respiration data 2 (5) 89 0.84 to 0.86 0.856 (0.72 to 0.93) 0.0000 0.1 (.79) 0

Respiration data and SpO2c 2 (5) 438 0.64 to 0.96 0.878 (–1.00 to 1.00) 0.6849 34.5 (<.01) 97

Respiration data and HRd data 2 (5) 158 0.89 to 0.90 0.894 (0.81 to 0.94) 0.0000 0.1 (.76) 0

Respiration data, HR data, and body movement 3 (8) 369 0.71 to 0.91 0.844 (0.38 to 0.97) 0.1030 24.5 (<.01) 92

Body movement, HR data, and SpO2 3 (8) 212 0.89 to 0.90 0.894 (0.88 to 0.91) 0.0000 0.1 (.93) 0
Validation method .90

K-fold cross-validation 4 (11) 527 0.64 to 0.96 0.869 (0.49-0.97) 0.2315 59.3 (<.01) 95

Train-test split 7 (18) 450 0.71 to 0.91 0.877 (0.82-0.92) 0.0486 50.8 (<.01) 88
Overall accuracy 12 (32) 1266 0.64 to 0.96 0.877 (0.82-0.92) 0.0828 194.5 (<.001) 94 e

aWD: wearable device.

bItalicized values are statistically significant (P<.05).

cSpO2: blood oxygen saturation.

dHR: heart rate.

eNot applicable.