Characteristics of included studies describing spirometry indices of primary ciliary dyskinesia patients
| Total studies | 24 (100) |
| Study size | |
| ≤20 patients | 8 (33) |
| 21–50 patients | 10 (42) |
| 51–100 patients | 2 (8) |
| >100 patients | 4 (17) |
| Number of centres | |
| Single centre | 17 (71) |
| Multicentre | 7 (29) |
| Publication period | |
| ≤1996 | 2 (8) |
| 1997–2007 | 7 (29) |
| ≥2008 | 15 (63) |
| Study region | |
| Europe | 15 (62.5) |
| Asia | 6 (25) |
| North and South America | 3 (12.5) |
| Age of participants | |
| Children <18 years | 7 (29) |
| Adults ≥18 years | 3 (13) |
| Children and adults | 14 (58) |
| Study design | |
| Retrospective | 11 (46) |
| Prospective | 13 (54) |
| Diagnostics performed | |
| Diagnosis based only on strong clinical suspicion | 2 (8) |
| Diagnosis based on EM or a combination of tests in most patients; few only on strong clinical suspicion# | 3 (13) |
| Diagnosis based on EM or a combination of tests in all patients# | 19 (79) |
| Spirometry indices reported | |
| FEV1 | 24 (100) |
| FVC | 12 (50) |
| Information for different age groups | 6 (43)¶ |
| Longitudinal information | 8 (33) |
Data are presented as n (%). EM: electron microscopy; FEV1: forced expiratory volume in 1 s; FVC: forced vital capacity. #: combination of the following: EM, nasal nitric oxide, high-frequency video-microscopy or light microscopy, or genetic analysis. ¶: of 14 studies including children and adults.