Table 2. Quality assessment of the included studies.
| Reasons for | Incomplete data | Efforts to address | ||||
| Consecutive | exclusion | adequately | potential sources | % loss to | ||
| First author and year | patients? | reported? | addressed? | of bias? | Follow-up time | follow-up |
| Research committee of | ||||||
| British Thoracic | Yes | Yes | Yes | Yes | 12 months | 8% |
| Society, 1992 | ||||||
| Agnelli, 2001 | Yes | Yes | Yes | Yes | at least 2 years | 0% |
| Agnelli, 2003 | Yes | Yes | Yes | Yes | at least 1 year | 0% |
| Agnelli, 2007 | Yes | Yes | Yes | Yes | at least 4 | 0% |
| months | ||||||
| Aujeskey, 2011 | Yes | Yes | Yes | Yes | 3 months | 0.2% |
| Van Bladel, 2010 | Yes | Yes | Yes | Yes | 3 months | 1.2% |
| Bona, 2000 | Yes | No | Unclear | Unclear | Unclear | Unclear |
| Büller, 2003 | Yes | Yes | Yes | Yes | 3 months | 0.5% |
| Büller, 2008 | Unclear | No | Yes | Yes | 3 months | 0.7% |
| Caprini, 1999 | Yes | Yes | No | No | 6 months | Unclear |
| Cassiopea, 2012 | Yes | Yes | Yes | Yes | 6–12 months | Unclear |
| Columbus Investigators, 1997 | Yes | Yes | Yes | Yes | 3 months | 0% |
| Das, 1996 | Yes | Yes | Yes | Yes | 3 months | Unclear |
| Daskapoulos, 2005 | Yes | Yes | Yes | Yes | 12 months | 0% |
| Einstein Investigators, 2010 | Yes | Yes | Yes | Yes | 3–12 months | 1% |
| Einstein Investigators, 2012 | Yes | Yes | Yes | Unclear | Unclear | 0.4% |
| Fiesinger, 2005 | Unclear | Yes | Yes | Yes | 6 ½ months | 1.1% |
| Galilei Investigators, 2004 | Yes | Yes | Yes | Yes | 3 months | 0% |
| Van Gogh Investigators, 2007 | Yes | Yes | Yes | Yes | 3 months | 0.8% |
| Gonzalez-Fajardo, 1999 | Yes | Yes | Yes | Yes | 12 months | 1.6% |
| Heidinger, 2000 | No | Yes | No | Unclear | Unclear | Unclear |
| Kearon, 1999 | Yes | Yes | Yes | Yes | Average 10 | Unclear |
| months | ||||||
| Kearon, 2003 | Yes | Yes | Yes | Yes | Average 2.4 | 0.1% |
| years | ||||||
| Kearon, 2004 | Yes | Yes | Yes | Yes | 12 months | 0% |
| Kearon, 2006 | Yes | Yes | Yes | Yes | 3 months | 0% |
| Koopman, 1996 | Yes | Yes | Yes | Yes | 6 months | 1% |
| Levine, 1995 | Unclear | Yes | No | Yes | 12 months | 3.4% |
| López-Beret, 2001 | Yes | Yes | Unclear | Unclear | 12 months | Unclear |
| Meyer, 2002 | Yes | Yes | Unclear | Unclear | 6 months | Unclear |
| Monreal, 1998 | Yes | Yes | Unclear | No | 3–6 months | Unclear |
| Nielsen, 1993 | Yes | No | Unclear | Yes | 3 months | Unclear |
| Palareti, 2000 | Yes | Yes | Yes | Yes | Average 10–11 | Unclear |
| months | ||||||
| Pérez-de-Llano, 2010 | Yes | Yes | Yes | Yes | 6 months | 6% |
| Pini, 1994 | Yes | Yes | Yes | Yes | 9 months | 0% |
| Poller, 2008 | Unclear | Yes | Unclear | Yes | Average 17 | Unclear |
| months | ||||||
| Poli, 2007 | Yes | Yes | Yes | Yes | At least 1 year | 8.1% |
| or until | ||||||
| recurrence | ||||||
| Prandoni, 2004 | Yes | Yes | Yes | Yes | 5 years | 1.7% |
| Santamaria, 2006 | Unclear | Yes | No | No | Median | Unclear |
| 98 days | ||||||
| Schulman, 1994 | Unclear | Yes | Yes | Yes | At least 6 | Unclear |
| months | ||||||
| Schulman, 2009 | Unclear | Yes | Yes | Yes | 6 months | 0.5% |