| Factor | Presence of co-morbidity N (%) | No co-morbidity N (%) | p value |
| N = 191 (54.4) | N = 160 (45.6) | ||
| Age (years) | 0.145 | ||
| 20 - 40 | 40 (11.4) | 46 (13.2) | |
| 41 - 60 | 58 (16.6) | 37 (10.5) | |
| Above 60 | 93 (26.4) | 77 (21.9) | |
| Duration (years) | 0.556 | ||
| ≤5 | 88 (25.1) | 71 (20.3) |
|
| 6 - 10 | 49 (13.9) | 49 (13.9) | |
| Above 10 | 54 (15.4) | 40 (11.4) |