Table 3.
Secondary outcomes
| Usual care plus doxycycline group | Usual care only group | Estimated treatment effect (95% CI) | p value | ||
|---|---|---|---|---|---|
| Sustained recovery | 502/780 (64·4%) | 396/644 (61·5%) | .. | .. | |
| Time to sustained recovery in days | 22 (9–not reached) | 22 (8–not reached) | 1·00 (0·88 to 1·14)* | 0·96 | |
| Alleviation of all symptoms | 618/671 (92%) | 522/551 (94·7%) | .. | .. | |
| Time to alleviation of all symptoms in days | 3 (2–7) | 3 (1–8) | 0·96 (0·86 to 1·09)* | 0·55 | |
| Sustained alleviation of all symptoms | 542/648 (83·6%) | 428/515 (83·1%) | .. | .. | |
| Time to sustained alleviation of all symptoms in days | 8 (3–23) | 10 (3–23) | 1·03 (0·90 to 1·17)* | 0·68 | |
| Initial reduction of severity of symptoms | 701/780 (89·9%) | 572/644 (88·8%) | .. | .. | |
| Time to initial reduction of severity of symptoms | 5 (1–12) | 4 (1–11) | 0·99 (0·88 to 1·11)* | 0·84 | |
| Rating of how well participant feels (1 worst, 10 best), mean (SD) [n] | |||||
| Day 7 | 7·1 (1·9) [757] | 7·0 (1·9) [636] | 0·05 (−0·16 to 0·25)† | 0·66 | |
| Day 14 | 7·8 (1·7) [752] | 7·7 (1·7) [632] | 0·06 (−0·16 to 0·28)† | 0·58 | |
| Day 21 | 8·1 (1·6) [689] | 8·0 (1·6) [566] | 0·00 (−0·25 to 0·25)† | 0·99 | |
| Day 28 | 8·3 (1·5) [754] | 8·3 (1·5) [629] | −0·06 (−0·34 to 0·22)† | 0·69 | |
| WHO-5 Well-Being Index score, mean (SD) [n] | |||||
| Day 14 | 45·4 (24·1) [738] | 44·3 (23·9) [616] | 0·20 (−2·06 to 2·45)† | 0·86 | |
| Day 28 | 54·5 (23·2) [737] | 53·8 (23·7) [605] | 0·01 (−2·25 to 2·28)† | 0·99 | |
| Self-reported contact with ≥1 health-care service | 381/773 (49·3%) | 314/642 (48·9%) | 1·04 (0·84 to 1·29)‡ | 0·72 | |
| General-practitioner reported contact with ≥1 health-care service | 203/381 (53·3%) | 181/345 (52·5%) | 0·99 (0·73 to 1·34)‡ | 0·96 | |
| Prescription of antibiotics | 18/341 (5·3%) | 20/306 (6·5%) | 0·81 (0·44 to 1·50)§ | 0·51 | |
| Hospital assessment without admission | 8/767 (1·0%) | 11/628 (1·8%) | 0·60 (0·24 to 1·47)§ | 0·35 | |
| Oxygen administration | 24/757 (3·2%) | 20/621 (3·2%) | 0·98 (0·55 to 1·76)§ | >0·99 | |
| Mechanical ventilation | 3/757 (0·4%) | 5/621 (0·8%) | 0·49 (0·12 to 2·05)§ | 0·48 | |
| Intensive care unit admission | 4/755 (0·5%) | 6/620 (1·0%) | 0·55 (0·16 to 1·93)§ | 0·36 | |
| Duration of hospital admission in days | 5 (3–8) | 7 (4–9) | −2·40 (−5·40 to 0·52)¶ | 0·10 | |
Data are n/N (%) or median (IQR) unless otherwise stated. All secondary outcome analyses were done on the concurrent randomisation analysis population, defined as all participants who were randomly assigned to usual care plus doxycycline or usual care only during the time period when the usual care plus doxycycline group was open to randomisation, and were restricted to these treatment groups only.
Estimated hazard ratio derived from a Cox proportional hazards model adjusted for age, comorbidity at baseline, duration of illness, and eligibility for doxycycline at baseline.
Mixed-effect model adjusted for age, comorbidity, duration of illness, eligibility for doxycycline at baseline, and time since randomisation; participants were fitted as a random effect; WHO-5 Well-Being Index score was also adjusted for score at baseline.
Relative risk adjusted for age, comorbidity at baseline, duration of illness, and eligibility for doxycycline at baseline.
Unadjusted relative risk due to low event rate.
Quantile regression adjusted for age, comorbidity, duration of illness, and eligibility for doxycycline at baseline.