Table 2. Frequency and incidence rate of complications among COVID-19 and influenza patients, South Korea*.
| Complications | Frequency† |
Incidence‡ |
Rate ratio (95% CI)§ | ||||
|---|---|---|---|---|---|---|---|
| COVID-19 | Influenza | p value¶ | COVID-19 | Influenza | |||
| Total |
4,139/21,615 (19.1) |
678,845/2,380,696 (28.5) |
<0.001 |
|
NA |
NA |
NA |
| Gastrointestinal disease | 856/12,089 (7.1) | 138,926/1,487,277 (9.3) | <0.001 | 11.39 | 14.57 | 0.78 (0.73–0.84) | |
| Musculoskeletal disorder | 772/9,712 (7.9) | 104,663/1,512,773 (6.9) | <0.001 | 13.24 | 17.57 | 0.75 (0.70–0.81) | |
| Periodontal disease | 953/7,121 (13.4) | 182,738/1,112,593 (16.4) | <0.001 | 15.61 | 24.02 | 0.65 (0.61–0.70) | |
| Skin disease | 797/14,638 (5.4) | 153,928/1,358,895 (11.3) | <0.001 | 9.56 | 10.70 | 0.89 (0.82–0.98) | |
| Hair loss | 67/21,364 (0.3) | 5,643/2,358,346 (0.2) | 0.02 | 0.46 | 0.30 | 1.52 (1.18–1.97) | |
| Asthma | 99/20,372 (0.5) | 61,699/1,990,519 (3.1) | <0.001 | 0.80 | 2.20 | 0.36 (0.28–0.47) | |
| COPD | 33/21,416 (0.2) | 4,048/2,362,939 (0.2) | 0.54 | 0.18 | 0.23 | 0.79 (0.54–1.15) | |
| Pneumonia | 419/20,189 (2.1) | 82,460/1,895,100 (4.4) | <0.001 | 3.0 | 2.94 | 1.02 (0.90–1.16) | |
| Cardiovascular disease | 88/20,849 (0.4) | 7,930/2,333,972 (0.3) | 0.42 | 0.56 | 0.54 | 1.05 (0.83–1.32) | |
| Heart failure | 73/21,306 (0.3) | 3,602/2,365,516 (0.2) | <0.001 | 0.34 | 0.18 | 1.88 (1.42–2.50) | |
| Cerebrovascular disease | 64/21,001 (0.3) | 5,020/2,353,824 (0.2) | 0.004 | 0.34 | 0.28 | 1.21 (0.91–1.60) | |
| Autoimmune disease | 119/20,759 (0.6) | 13,813/2,307,629 (0.6) | 0.64 | 0.87 | 0.84 | 1.03 (0.86–1.25) | |
| Mood disorder | 381/19,916 (1.9) | 23,993/2,279,373 (1.1) | <0.001 | 2.80 | 1.61 | 1.73 (1.56–1.93) | |
| Dementia | 106/20,921 (0.5) | 5,534/2,358,412 (0.2) | <0.001 | 0.40 | 0.21 | 1.96 (1.52–2.55) | |
*COPD, chronic obstruction pulmonary disease; COVID-19, coronavirus disease; NA, not applicable. †The numerator is the number of persons who experienced complications in the disease-free population and the denominator is the number of persons who did not have a history of the selected complication within a 3-y period before COVID-19 or influenza infection. The proportion is cumulative incidence. ‡Age-standardized incidence (cases per 1,000 person-months) for COVID-19 was divided by the standardized incidence rate for influenza and standardized to the 2020 population. §Rate ratios are standardized to the 2020 population. ¶χ2 tests were performed to assess the difference in proportion between COVID-19 and influenza patients.