Table 2.
Subgroup analysis of all included studies.
| Factor | Studies | Sensitivity (95% CI) | I2 | Model used | Specificity (95% CI) | I2 | Model used | SROC (95% CI) |
|---|---|---|---|---|---|---|---|---|
| All studies | 31 | 0.85 (0.81–0.88) | 77.87% | Random | 0.85 (0.81–0.88) | 95.48% | Random | 0.91 (0.89–0.94) |
| Type of the device | ||||||||
| COPD-6 | 14 | 0.84 (0.80–0.88) | 79.22% | Random | 0.85 (0.79–0.90) | 95.85% | Random | 0.91 (0.88–0.93) |
| Piko-6 | 6 | 0.89 (0.76–0.96) | 84.17% | Random | 0.88 (0.75–0.94) | 96.11% | Random | 0.95 (0.92–0.96) |
| PEF | 4 | 0.77 (0.73–0.81) | 1.13% | Fixed | 0.83 (0.71–0.91) | 94.04% | Random | 0.82 (0.78–0.85) |
| Hi-checker | 2 | 0.75 (0.63–0.84) | 91.20% | Random | 0.86 (0.82–0.90) | 92.80% | Random | – |
| IQ-spiro | 1 | 0.94 | – | – | 0.92 | – | – | – |
| SP10BT | 1 | 0.83 | – | – | 0.75 | – | – | – |
| Medikro SpiroStar | 1 | 0.92 | – | – | 0.84 | – | – | – |
| MS01 Micro spirometer | 1 | 0.89 | – | – | 0.58 | – | – | – |
| Spirobank Smart | 1 | 0.83 | – | – | 0.92 | – | – | – |
| Detection indicators | ||||||||
| PEF | 4 | 0.77 (0.73–0.81) | 1.13% | Fixed | 0.83 (0.71–0.91) | 94.04% | Random | 0.82 (0.78–0.85) |
| FEV1/FVC | 4 | 0.85 (0.81–0.88) | 6.47% | Fixed | 0.80 (0.65–0.90) | 96.14% | Random | 0.87 (0.84–0.90) |
| FEV1/FEV6 | 23 | 0.85 (0.81–0.89) | 82.09% | Random | 0.86 (0.81–0.90) | 95.54% | Random | 0.92 (0.90–0.94) |
| Threshold selection method | ||||||||
| Fixed | 4 | 0.83 (0.65–0.92) | 90.39% | Random | 0.89 (0.79–0.94) | 94.40% | Random | 0.93 (0.90–0.95) |
| Cutoff | 19 | 0.86 (0.81–0.89) | 80.62% | Random | 0.85 (0.80–0.90) | 95.43% | Random | 0.92 (0.89–0.94) |
| P | 0.673 | 0.385 | 0.581 | |||||
| Type of indicators | ||||||||
| Multi-index | 27 | 0.85 (0.82–0.88) | 79.21% | Random | 0.85 (0.81–0.89) | 95.60% | Random | 0.92 (0.89–0.94) |
| Single index | 4 | 0.77 (0.73–0.81) | 1.13% | Fixed | 0.83 (0.71–0.91) | 94.04% | Random | 0.82 (0.78–0.85) |
| P | <0.001 | 0.716 | <0.001 | |||||
| Country | ||||||||
| Developed | 23 | 0.85 (0.81–0.88) | 73.60% | Random | 0.83 (0.78–0.87) | 95.52% | Random | 0.90 (0.88–0.93) |
| Developing | 8 | 0.84 (0.77–0.89) | 88.47% | Random | 0.90 (0.85–0.93) | 96.57% | Random | 0.94 (0.91–0.95) |
| P | 0.778 | 0.023 | 0.015 | |||||
| Executive place | ||||||||
| Tertiary hospital | 10 | 0.89 (0.83–0.93) | 81.27% | Random | 0.92 (0.89–0.95) | 82.86% | Random | 0.96 (0.94–0.97) |
| Primary care/community | 21 | 0.83 (0.79–0.87) | 76.98% | Random | 0.80 (0.75–0.85) | 95.97% | Random | 0.89 (0.86–0.91) |
| P | 0.066 | <0.001 | <0.001 | |||||
| Study setting | ||||||||
| Hospital-based | 27 | 0.85 (0.81–0.88) | 77.64% | Random | 0.85 (0.80–0.89) | 95.81% | Random | 0.91 (0.89–0.93) |
| Population-based | 4 | 0.85 (0.78–0.90) | 86.53% | Random | 0.87 (0.84–0.90) | 94.79% | Random | 0.93 (0.90–0.95) |
| P | 0.999 | 0.469 | 0.222 | |||||
| Population | ||||||||
| No COPD | 13 | 0.86 (0.78–0.91) | 80.71% | Random | 0.87 (0.81–0.92) | 94.67% | Random | 0.93 (0.90–0.95) |
| The whole crowd | 18 | 0.84 (0.81–0.87) | 76.22% | Random | 0.83 (0.78–0.87) | 95.81% | Random | 0.90 (0.87–0.93) |
| P | 0.584 | 0.271 | 0.133 | |||||
| Publication year | ||||||||
| 2000–2016 | 15 | 0.83 (0.79–0.86) | 66.10% | Random | 0.83 (0.77–0.87) | 95.94% | Random | 0.89 (0.86–0.92) |
| 2017–2021 | 16 | 0.86 (0.80–0.90) | 83.90% | Random | 0.87 (0.81–0.91) | 95.02% | Random | 0.92 (0.89–0.95) |
| P | 0.336 | 0.267 | 0.178 | |||||
The study divides countries into developed and developing countries according to HDI. When HDI > 0.80, it is classified as a developed country and if otherwise, developing country59.
SROC summary receiver operating characteristic curve.
aOwing to the complexity of the bivariate model and the limited number of studies, the groups with n ≥ 4 were pooled using a bivariate model. The remaining data were pooled by univariate random-effects logistic regression model. We also tested for the difference in the sensitivity or specificity between the two groups using the bivariate model. The AUC difference in the area under the SROC between the groups was obtained by Z test.