Adjusted incidence rate ratios of physician visits by follow-up period*
| Variable | Incidence rate ratio (95% CI) | ||||
|---|---|---|---|---|---|
| Model 1: 1–30 d | Model 2: 31–60 d | Model 3: 61–90 d | Model 4: 90–180 d | Model 5: ≥ 180 d | |
| Patient group | |||||
| COVID-19 (ICU admitted) | 2.06 (1.85 to 2.29) | 1.60 (1.43 to 1.79) | 1.32 (1.17 to 1.49) | 1.18 (1.05 to 1.33) | 0.88 (0.70 to 1.09) |
| COVID-19 (hospitalized) | 1.61 (1.51 to 1.71) | 1.32 (1.23 to 1.41) | 1.19 (1.11 to 1.28) | 1.16 (1.09 to 1.24) | 0.98 (0.87 to 1.11) |
| Controls | Ref. | Ref. | Ref. | Ref. | Ref. |
| Age group, yr | |||||
| ≥ 65 | 1.52 (1.40 to 1.64) | 1.48 (1.36 to 1.61) | 1.59 (1.46 to 1.74) | 1.60 (1.47 to 1.73) | 1.42 (1.23 to 1.65) |
| 45–64 | 1.21 (1.12 to 1.32) | 1.15 (1.06 to 1.26) | 1.22 (1.11 to 1.33) | 1.25 (1.16 to 1.36) | 1.10 (0.96 to 1.27) |
| 0–24 | 0.98 (0.85 to 1.13) | 1.07 (0.91 to 1.24) | 0.92 (0.79 to 1.09) | 0.95 (0.83 to 1.09) | 0.66 (0.50 to 0.87) |
| 25–44 | Ref. | Ref. | Ref. | Ref. | Ref. |
| Sex, female | 0.98 (0.93 to 1.03) | 1.03 (0.97 to 1.09) | 1.05 (0.99 to 1.12) | 1.12 (1.06 to 1.18) | 1.10 (0.99 to 1.22) |
| Deprivation quintile | |||||
| Lowest (most deprived) | 1.04 (0.96 to 1.14) | 0.98 (0.89 to 1.07) | 1.12 (1.02 to 1.23) | 1.09 (1.00 to 1.19) | 1.17 (0.99 to 1.38) |
| Lower middle | 1.06 (0.97 to 1.16) | 0.95 (0.86 to 1.04) | 1.03 (0.94 to 1.14) | 1.02 (0.93 to 1.12) | 1.02 (0.86 to 1.21) |
| Middle | 1.00 (0.92 to 1.10) | 0.85 (0.77 to 0.93) | 0.96 (0.87 to 1.06) | 0.89 (0.81 to 0.97) | 1.03 (0.87 to 1.22) |
| Upper middle | 0.99 (0.90 to 1.08) | 0.87 (0.79 to 0.96) | 0.91 (0.82 to 1.02) | 0.99 (0.91 to 1.09) | 1.00 (0.84 to 1.20) |
| Highest (least deprived) | Ref. | Ref. | Ref. | Ref. | Ref. |
| Region (zone) | |||||
| North | 0.81 (0.73 to 0.90) | 0.77 (0.69 to 0.87) | 0.71 (0.63 to 0.80) | 0.72 (0.65 to 0.80) | 0.62 (0.52 to 0.76) |
| Central | 0.89 (0.81 to 0.98) | 0.94 (0.85 to 1.04) | 0.92 (0.82 to 1.02) | 0.90 (0.82 to 0.99) | 0.85 (0.70 to 1.04) |
| Calgary | 1.09 (1.03 to 1.16) | 1.04 (0.98 to 1.11) | 1.09 (1.02 to 1.16) | 1.05 (0.99 to 1.12) | 1.15 (1.01 to 1.31) |
| South | 0.91 (0.80 to 1.03) | 0.80 (0.70 to 0.93) | 0.88 (0.76 to 1.02) | 0.85 (0.75 to 0.97) | 0.90 (0.75 to 1.09) |
| Edmonton | Ref. | Ref. | Ref. | Ref. | Ref. |
| Comorbidities | |||||
| ≥ 3 | 1.86 (1.71 to 2.03) | 1.82 (1.66 to 1.99) | 1.85 (1.68 to 2.04) | 1.82 (1.66 to 1.99) | 1.98 (1.66 to 2.37) |
| 2 | 1.52 (1.39 to 1.66) | 1.52 (1.38 to 1.67) | 1.60 (1.45 to 1.76) | 1.52 (1.39 to 1.67) | 1.27 (1.06 to 1.51) |
| 1 | 1.17 (1.07 to 1.27) | 1.17 (1.07 to 1.28) | 1.22 (1.11 to 1.34) | 1.17 (1.08 to 1.28) | 1.27 (1.08 to 1.48) |
| 0 | Ref. | Ref. | Ref. | Ref. | Ref. |
| Prior visits (last 12 mo) | |||||
| ≥ 10 | 4.74 (4.30 to 5.22) | 4.32 (3.90 to 4.79) | 3.74 (3.37 to 4.15) | 3.45 (3.15 to 3.77) | 2.58 (2.17 to 3.07) |
| 5–9 | 1.95 (1.76 to 2.17) | 1.73 (1.55 to 1.94) | 1.77 (1.58 to 1.98) | 1.66 (1.51 to 1.83) | 1.62 (1.36 to 1.94) |
| 0–4 | Ref. | Ref. | Ref. | Ref. | Ref. |
| ED or UCC visits (last 12 mo) | |||||
| ≥ 2 | 1.36 (1.25 to 1.47) | 1.47 (1.35 to 1.60) | 1.49 (1.36 to 1.63) | 1.48 (1.36 to 1.61) | 1.19 (1.02 to 1.38) |
| 1 | 1.10 (1.02 to 1.18) | 1.14 (1.06 to 1.24) | 1.13 (1.04 to 1.22) | 1.12 (1.04 to 1.21) | 0.95 (0.83 to 1.09) |
| 0 | Ref. | Ref. | Ref. | Ref. | Ref. |
| Hospital admission (last 12 mo) | 0.97 (0.89 to 1.05) | 0.98 (0.90 to 1.08) | 1.00 (0.91 to 1.10) | 1.05 (0.96 to 1.15) | 1.41 (1.20 to 1.65) |
Note: CI = confidence interval, ED = emergency department, ICU = intensive care unit, Ref. = reference category, UCC = urgent care clinic.
↵* The table presents the incidence rate ratios from negative binomial regression analyses for the number of physician visits of the individuals in each of the 5 follow-up periods. Model covariates included age group, sex, deprivation index, zone, comorbidity count categories and physician visits, ED or UCC visits, and hospital admission (Y/N) in the prior year. Model intercept, coefficients and model-fit statistics are reported in Appendix 1, Table A5 (available at www.cmajopen.ca/content/11/4/E706/suppl/DC1).