Table 2.
Loss to follow-up and mortality in immigrants and long-term residents in Ontario, Canada
| Ischaemic stroke | Cancer | Schizophrenia | ||||
| Immigrants | Long-term residents | Immigrants | Long-term residents | Immigrants | Long-term residents | |
| N (%) | 2078 (8.5) | 22 479 (91.5) | 26 084 (8.4) | 284 445 (91.6) | 9525 (17.4) | 45 166 (82.6) |
| Loss to follow-up, n (%) | 158 (7.6) | 512 (2.3) | 2016 (7.7) | 5995 (2.1) | 1238 (13.0) | 3748 (8.3) |
| Adjusted HR of loss to follow-up (95% CI)* accounting for the competing risk of death | 2.87 (2.38 to 3.44) | 1.00 | 3.07 (2.91 to 3.23) | 1.00 | 1.54 (1.44 to 1.64) | 1.00 |
| Death, n (%) | 796 (35.4) | 12 575 (55.9) | 9014 (34.6) | 146 723 (51.6) | 546 (5.7) | 6647 (14.7) |
| Unadjusted HR of death (95% CI) | 0.61 (0.56 to 0.65) | 1.00 | 0.60 (0.59 to 0.62) | 1.00 | 0.39 (0.35 to 0.42) | 1.00 |
| Adjusted HR* (95% CI) not accounting for loss to follow-up | 0.78 (0.73 to 0.84) | 1.00 | 0.74 (0.73 to 0.76) | 1.00 | 0.54 (0.50 to 0.59) | 1.00 |
| Adjusted HR* (95% CI) accounting for loss to follow-up | 0.83 (0.77 to 0.89) | 1.00 | 0.78 (0.76 to 0.79) | 1.00 | 0.56 (0.51 to 0.61) | 1.00 |
| Sensitivity analyses‡ | ||||||
| Death within 30 days of loss to follow-up Adjusted HR (95% CI) |
0.93 (0.87 to 1.00) | 1.00 | 0.90 (0.88 to 0.91) | 1.00 | 1.00 (0.95 to 1.05) | 1.00 |
| Death within 1 year of loss to follow-up Adjusted HR (95% CI) |
0.93 (0.87 to 0.99) | 1.00 | 0.89 (0.87 to 0.91) | 1.00 | 1.00 (0.95 to 1.06) | 1.00 |
*Multivariable model adjusting for the following: age, sex, neighbourhood-level income, and comorbidities (known hypertension, diabetes, congestive heart failure, chronic obstructive pulmonary disease, and atrial fibrillation).
†Censoring those who were lost to follow-up, which was determined when date of last health system contact occurred before end of follow-up among those alive.
‡Assigning date of death among those lost to follow-up and recalculating adjusted hazard of death.