Table 2.
Antibiotic Prescribing Rates (per 1000 Person-Days) and Incidence Rate Ratio (Relative to Self-controlled periods) of Antibiotic Prescribing, for Older Residents of Nursing Homes With Confirmed Severe Acute Respiratory Syndrome Coronavirus 2, Stratified by Selected Covariates and by Prediagnosis, Postdiagnosis, and Self-controlled Periods
| Variable | Prediagnosis | Postdiagnosis | Control Period | |||
|---|---|---|---|---|---|---|
| Rate | IRR (95% CI) | Rate | IRR (95% CI) | Rate | IRR | |
| All | 14.97 | 3.52 (3.28–3.77) | 20.92 | 4.92 (4.59–5.27) | 4.25 | Ref |
| Age, y | ||||||
| 65–74 | 15.92 | 3.41 (2.83–4.10) | 22.02 | 4.71 (3.89–5.70) | 4.67 | Ref |
| 75–84 | 15.76 | 3.57 (3.15–4.06) | 20.33 | 4.61 (4.05–5.24) | 4.41 | Ref |
| ≥85 | 14.37 | 3.52 (3.21–3.86) | 20.99 | 5.14 (4.70–5.63) | 4.08 | Ref |
| Sex | ||||||
| Female | 13.98 | 3.29 (3.03–3.58) | 19.06 | 4.49 (4.13–4.88) | 4.24 | Ref |
| Male | 17.13 | 4.01 (3.53–4.55) | 25.14 | 5.88 (5.20–6.65) | 4.27 | Ref |
| COVID-19 vaccine | ||||||
| <2 doses | 15.00 | 3.59 (3.34–3.85) | 21.43 | 5.12 (4.77–5.50) | 4.19 | Ref |
| ≥2 doses | 14.56 | 2.81 (2.18–3.63) | 14.40 | 2.78 (2.13–3.64) | 5.18 | Ref |
| Index period | ||||||
| January–June 2020 | 18.33 | 4.31 (3.86–4.83) | 18.71 | 4.40 (3.91–4.96) | 4.25 | Ref |
| July–December 2020 | 12.75 | 3.11 (2.75–3.51) | 20.58 | 5.02 (4.45–5.66) | 4.10 | Ref |
| January–June 2021 | 13.34 | 3.14 (2.71–3.63) | 26.54 | 6.24 (5.46–7.14) | 4.25 | Ref |
| July–December 2021 | 13.95 | 2.66 (2.03–3.50) | 13.17 | 2.52 (1.87–3.38) | 5.23 | Ref |
Abbreviations: CI, confidence interval; COVID-19, coronavirus disease 2019; IRR, incidence rate ratio; Ref, reference.