Case-crossover | Self-controlled case-series | |
---|---|---|
N = 53 | N = 55 | |
Major assumptions: | ||
Type of studied exposure | ||
Intermittent/transient | 34 (64) | 49 (89) |
Sustained | 11 (21) | 5 (9) |
Unclear | 8 (15) | 1 (2) |
Event onset | ||
Abrupt | 52 (98) | 53 (96) |
Insidious | 1 (2) | 2 (4) |
Rare event | 46 (87) | 48 (87) |
Recurrent event (for self-controlled case series only) | - | 42 (76) |
Rare and/or recurrent event (for self-controlled case series only) | - | 55 (100) |
All major validity assumptions fulfilleda | 35 (66) | 48 (87) |
Minor assumptions: | ||
Same opportunity of exposureb | 34/35 (97) | - |
Time trend in exposure | ||
Yes | 8/35 (23) | - |
In case of exposure time trend, the design is adapted | 5/8 (63) | |
No | 5/35 (14) | - |
Unclear | 22/35 (63) | - |
Absence of exposure time trend (or design adapted) | 32/35 (91) | |
Independence of consecutive events | ||
Yes | - | 5/48 (10) |
No | - | 17/48 (35) |
For non-independent recurrences, the design is adapted | 16/17 (94) | |
Unclear | - | 14/48 (29) |
Not applicable (for non-recurrent events) | - | 12/48 (25) |
Independence of consecutive events when recurrent (or design-adapted)c | - | 47/48 (98) |
Event-independent exposure | ||
Yes | - | 5/48 (10) |
No | - | 38/48 (79) |
For non-event-independent recurrences, the design is adapted | 32/38 (84) | |
Unclear | - | 5/48 (10) |
Event-independent exposure (or design-adapted)d | - | 42/48 (88) |
The event affects the short-term mortality probability (censoring of the observation period) | - | |
Yes | - | 12/48 (25) |
For event-dependent censoring, the design is adapted | 4/12 (33) | |
No | - | 36/48 (75) |
Absence of censoring the observation period (or design-adapted)e | - | 40/48 (83) |
All minor validity assumptions fulfilled for use of a self-controlled design (among articles with valid major assumptions)f | 31/35 (89) | 34/48 (71) |
All major and minor validity assumptions fulfilled for use of a self-controlled design (among all articles) | 31/53 (58) | 34/55 (62) |